In a recent contribution to ChemEd X "Stoichiometry is Easy", the author states that he has "vacillated over the years between using an algorithmic method, and an inquiry-based approach to teaching stoichiometry." I would like to suggest that there is another approach to mastering stoichiometry and that it should precede the algorithmic one: it is the conceptual approach based on a particle model to represent the species involved in chemical reactions.

Most teachers, and I include among them those responsible for writing the items for the high-stakes tests the author describes, have a tendency to equate quantitative fluency with a genuine understanding of the underlying processes. After all, if students can correctly determine the mass of a product to be expected or which is the limiting reactant, then certainly they must know what is going on during the reaction, right? Unfortunately, as researchers such as Craig Bowen and Diane Bunce¹ have shown, typical quantitative test items don't probe whether students have persistent naïve conceptions about chemical reactions and processes.

The 5-step algorithm "Stoichiometry is Easy" to the tune of "Hark the Herald Angels Sing" described by the author is catchy and appears to be effective. But l believe that learning any algorithm is most effective when it follows an introduction stressing conceptual understanding. As Dudley Herron² wrote about algorithms:

For similar reasons, I teach efficient algorithms for such routine tasks as balancing chemical equations (after I am convinced that the student knows what a balanced equation is and why we want one) and encourage students to use them. I emphasize the point that the algorithm should be sensible (i.e., we know what the product of the procedure means) but should not require them to think any more than necessary. Indeed, the purpose of an algorithm is to reduce the load on working memory and save time. [My emphasis]

In the approach advocated by Modeling Instruction in High School Chemistry³, students use particle diagrams depicting the reaction mixture before and after a reaction has occurred to make the point that the balanced chemical equation relates numbers of particles, not mass or volume, the quantities we typically use to measure how much stuff is involved. The use of a BCA (before-change-after) table, similar to the ICE table used in a quantitative treatment of equilibrium mixtures, helps students connect the particle diagrams to a more convenient way of representing the ratio of reacting species. Consider the example below:

Note: xs is shorthand for "excess"

The first examples involve calculations that can be done in one's head and easily related to particle diagrams. By this time students have learned that moles are simply weighable amounts of given species, so they readily accept that the ratios of coefficients relate to numbers of particles. What happens if the information about the situation is given in terms of mass? One has to apply techniques learned in an earlier unit to convert the givens to moles, chemists' counting unit. If the desired quantity is mass (or volume), then that calculation is done on the side using the molar mass or molar volume as the required conversion factor.

The particle diagrams are especially useful when dealing with limiting reactant problems. Consider the reaction in which water is produced when hydrogen and oxygen gas react.

2 H₂ + O₂→ 2 H₂O

The reactant mixture might look like the box at left. Students are encouraged to cross out reacting species and draw in product species until the reaction can no longer proceed. They should end up drawing a product mixture as shown in the "after" box.

Before	After
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The corresponding BCA table appears below:

Once students recognize the connection between the numbers in the table and the particle diagrams for these "obvious" examples, it's a straightforward step to examining cases where one might have to guess which reactant is consumed first. Consider the reaction between aluminum and iodine to produce aluminum iodide.

Here, the typical student guess - that the reactant with the fewest number of moles available is limiting - leads to an obvious problem when one multiplies the 0.50 moles of Al by the 3/2 ratio given in the balanced equation. Students reassess and assume that all of the iodine must be consumed in the reaction and complete the table correctly as follows.

This approach not only shows the correct number of moles of aluminum iodide produced, but also how many moles of the excess reactant remain.

One might argue, "Well, isn't using the table just a different algorithm?" This might be true if it weren't for the fact that the instructor explicitly connects the values that populate the table with particle diagrams when the students first encounter its use. When a serious effort is made to make the "steps" in a procedure sensible to students, they are more likely to understand what they are doing as they are doing it.

References

1. Bowen, C. and Bunce, D., "Testing for Conceptual Understanding in General Chemistry" The Chemical Educator, Vol. 2, No 2, 1997
2. Herron, J. Dudley. The Chemistry Classroom, The American Chemical Society, 1996
3. American Modeling Teachers Association, http://modelinginstruction.org

TV and movie screens today offer us a desperate fight against crazy-fast zombies, a peek into celebrities’ lives where truth is often stranger than fiction, million-dollar game shows, and more. Can portraits of science compete? Last month I watched a new PBS series “The Mystery of Matter: Search for the Elements” to see what it might bring to the education (and entertainment) table.

The series premiered in Oregon, with a national release planned for sometime in 2015. An email from the American Chemical Society Portland Local Section alerted its members to the series. What intrigued me was that it would feature actors portraying the scientists, speaking (when possible) the words of the scientists themselves, and showing re-enactments of various experiments using replica scientific equipment from those historical periods. Its blog site describes it as being “about the amazing human story behind the Periodic Table” (http://mystery-of-matter.blogspot.com). Short promotional videos with scenes from the series are online (http://vimeo.com/user14321084).

I caught the first and last episodes out of three. The first focused on Joseph Priestley, Antoine Lavoisier, and Humphry Davy; the second Marie Curie and Dmitri Mendeleev; the third Henry Moseley and Glenn Seaborg. Host Michael Emerson narrated portions featuring each scientist. I found it difficult to see and hear him without automatically thinking of his creepy Ben Linus character from the TV series Lost. Two years ago there was a call for applications for the host spot, preferably someone from the chemistry community, so his choice is a departure from that (http://cenblog.org/newscripts/2012/02/your-chance-to-host-a-pbs-program-about-chemistry/).

Each episode was about an hour long. Portions focusing on each particular scientist were fairly stand-alone, so those shorter chunks could fit into the typical length of a high school class period. The entire episode is interspersed with sections from the host as well as short comments from various scientists. These additional people tended to be older white males. I wondered why no women and only one minority were tapped for these brief pieces in the two episodes I saw. 

The highlight of the first episode for me was the section on Davy. Less well known than the often-mentioned Priestley and Lavoisier, I appreciated the attention paid to his contribution to the periodic table. Davy cut a youthful and adventuresome (reckless, perhaps?) figure, which might appeal to high school students. One example is a clip of Davy testing laughing gas on himself and his companions (http://vimeo.com/109155827). There are several instances in the episodes where the safety practices of the past could be compared with those used now. It also showed him as a famous figure of the day, with women admirers attending his packed chemistry demonstration shows.

The third episode was more engaging to me than the first. Lots of scientist names (a feel of scientist celebrities, in my mind) in the mix with various links to each other, with Rutherford, Chadwick, James Bryant Conant, and Fermi. It was interesting to see the role that war played in the lives of both Moseley and Seaborg. Even the small details of the episode were fascinating—vacuum pumps being jealously guarded in the lab, with Moseley creating a way around his lack of one; the use of cigarette papers to carry out an experiment.

Along with the national release, a blog about the series promises additional materials that would be useful for educators (http://mystery-of-matter.blogspot.com/2014/10/other-project-components-in-addition-to.html). These include a teacher’s edition, a dozen web videos “made expressly for chemistry teachers from material shot for the television series,” and an outreach plan for sharing the concepts of matter with others.

I look forward to seeing the second episode that I missed and exploring the promised accompanying educational materials. Two ways to stay up to date on the series and its release are at its Facebook page (https://www.facebook.com/mysteryofmatter) and blog (http://mystery-of-matter.blogspot.com). It would be an excellent tool for bringing students a different view of the periodic table and those involved in its history.

Any Oregonians out there who saw it already? What did you think?

Whenever a serious incident takes place in a school chemistry laboratory or classroom, fire and safety officers often pontificate on the incident by quoting the Materials Safety Data Sheet (MSDS). However, how many of you have read such documents in full? In UK schools we have perhaps 200 to 400 chemicals on the shelves. Have you read the MSDSs for each chemical? Did you even know there was such a thing as a MSDS or do you just “always read the label”. In the UK, we have many very experienced school laboratory technicians who do have access to the MSDSs and to a large extent, protect the teacher and so I suspect there are many teachers who do not know that they exist. If they had been told about them, it was years ago in University perhaps. In the UK and the USA, we have to store the MSDS sheets electronically or in a filing cabinet. I suspect once in the storage area they are never read.

They are silly

This statement may seem impudent in the extreme. After all, many really well-qualified chemists and toxicologists in the United Nations, Occupational Safety & Health Administration (OSHA), European Chemical Agency (EChA), Health and Safety Executive(HSE) and countless other organisations in all the developed countries in the world have spent many hours of serious debate and research on implementing GHS. The aim is to ensure that the same information is available on chemicals no matter which continent you are in.

Yet I can show the section on sodium chloride and sterile water in Figs 1a and 1b to any experienced chemistry teacher and the response will be “This is silly”.

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Figure 1a from a MSDS for sodium chloride

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Figure 1b from a MSDS for First Aid measures for exposure to sterile water

You can imagine the coffee-time discussion amongst teachers and lecturers of chemistry discussing and ultimately dismissing these documents in no uncertain terms as “unbelievable”. The issue now is that the MSDS loses its credibility amongst the experienced chemists; that can be dangerous and a complete disregard of the use of MSDS may be illegal.

It is obvious that a computer is at work but with companies supplying thousands of chemicals mostly to Industry, Hospitals and Universities and only a small percentage to Schools and Colleges I hope you can see the suppliers’ problem. The format of these MSDS documents are enshrined in the advice from the United Nations.

They are simply wrong

UK schools have informed CLEAPSS of any hazards which seemed to be different from those they had previously received. I remember the first one. Vaseline (usually no hazard classification) was ordered by a school from a supplier but it came with a carcinogen warning. The school contacted the educational supplier but the reply was “It is the new laws”. It was only when the school contacted our organization, worried that they had been using a substance which was carcinogenic, for tens of years with students that we managed to get the supplier to go to their supplier to confirm that the wax should not be classified as carcinogenic. Now, there was a reason for the hazard warning because if any supplier was taking the information from the ECHA website, Petrolactum or Vaseline did carry a carcinogen warning but with this comment: “The classification as a carcinogen need not apply if the full refining history is known and it can be shown that the substance from which it is produced is not a carcinogen”. This comment is easily missed. The suppliers have made other mistakes and poor interpretations of the law. They are learning to cope with the new legislation as it is acknowledged to be very complicated. What teachers might not realise is that a MSDS is generated when the chemical enters or is manufactured in the country. The information has to be passed down to the next outfit in the supply chain and so on until your school buys the chemical. In this game of “whispers” mistakes are bound to happen.

A sole teacher in a small school was frightened to open a bottle of magnesium powder (required by an exam board for an assessed practical exam) because on the label it said H250: Catches fire spontaneously if exposed to air. Again, there had to be careful reading of the documentation because a Note said that “This substance may be marketed in a form which does not have the physical hazards as indicated by the classification”.

The UK is fortunate to have a HSE Helpline, The Environment Health & Safety Committee at the Royal Society of Chemistry and the Chemical Hazards Communication Group (industrial) for advice and help. The HSE and the RSC are vociferous in their support of chemistry practical work in schools. It is necessary to work with the system and not against it.

They are emotive

What does the word “fatal” conjure up in your mind? “There has been a fatal accident” on the news suggests a person has immediately died but in GHS speak it means very toxic. Figure 2 is taken from a supplier’s MSDS sheet on sebacoyl chloride, a chemical we use in the UK in schools to do the “nylon rope experiment” and CLEAPSS received a number of calls on the word “fatal” and the question “is it banned?” In fact, the degree of hazard had not changed from before GHS, but then it was written as “very toxic in contact with the skin” and nobody made a comment about that. In fact I actually poured 2 to 3 ml of this solution on my hand, washed it off and I am still here.

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Figure 2

The hazard ratings for chemicals are not given “on the nod” but need criteria as provided in guidance in a document called the Purple Book. The testing criteria can be found in the Organisation for Economic Cooperation and Development Library. It does involve animal testing but one is assured this is kept to a minimum. Because of the complexity of the area, suppliers do get it wrong, especially as countries adopt the new GHS system, and if it seems wrong to you, your professional body may be the first point of call as they do have a safety section. Communicating this information to non-scientists or even scientists of a different persuasion can be difficult.

They do not take into account dilution (“The dose makes the poison” – Paracelsus)

The school buys sodium hydroxide pellets. The teacher/technician makes a solution and dilutes the solution to 0.1M. The MSDS sheet is only relevant to the person making the solution as it makes no comment about dilution. Even if you buy a dilute solution, the true hazard classification of the product can be hidden in the wording of the MSDS sheet. I have seen MSDS sheets for 0.2M sodium hydroxide which quote the hazards of solid sodium hydroxide with no mention of the reduction of hazard caused by dilution.

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Figure 3a

These cut off concentrations differ for every substance because it is calculated by percentage by mass of substance or element present. So the dividing lines for dilution effects are different for potassium and sodium hydroxide solutions. I once questioned this and was told the mole concept is not well understood. Having taught it and knowing the difficulties, I agreed but also wondered why we teach it if industry does not use it!

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Figure 3b

CLEAPSS does have direct evidence for the severity of the hazard when a 2M solution was poured over a student’s eye in a fight (not a Health & Safety issue, this is assault) and caused blindness but when solutions below 0.5M have ever entered the eye and eye irrigation has been applied, there has been no permanent damage.

Naturally, the same applies to toxic chemicals. Copper(II) sulfate(VI) solutions lose the Harmful if swallowed warning at concentrations less than 1M and solutions at concentrations less than 0.6M have no hazard warning. This does not mean that teachers have a free hand to do what they like with 0.5M copper(II) sulfate(VI) solution; good laboratory etiquette is important at all times.

The changes to hazard classification with dilution are very important when it comes to carrying out risk assessments.

They do not take into account exposure time

I hope you now realise that the MSDS, although useful, is more relevant to those in industry who are working with a chemical 8 hours a day for a year. Obviously, in those conditions the degree of exposure is considerably higher. The word “exposure” is unfortunate because in law and the tabloid press, it can mean all sorts of unsavory habits of certain individuals with weird minds. In the world of toxicology, looking at a chemical such as lead nitrate is not going to cause you a problem. Exposure means intake into the body by 3 possible routes, ie, inhalation, ingestion and through the skin (the dermal and ocular route). Some chemicals do have an immediate effect (acute); sulfur dioxide and chlorine can cause breathing difficulties but we, as teachers, should know this and use appropriate control measures to minimise exposure. I use a microscale method of electrolyzing copper chloride solution which produces only about 6 cm³ of gas in a Petri dish. If I am reacting chlorine in a gas jar with sodium or iron, I would use a fume hood (cupboard), which vents the gas to the atmosphere or absorbs it into a filter.

There are now hazard warnings about borax causing harm to the unborn child but the evidence is from mining the solid with poor safety instructions. Nickel solutions cause nasal cancers but the evidence comes from badly controlled electroplating works. The route is via inhalation of nickel so how is that going to happen in a school laboratory? Reacting nickel carbonate with acid and electroplating nickel can cause an aerosol. In the UK, despite the degree of exposure being very tiny, we still warn and will take effective methods. Zinc electroplating illustrates the procedure just as well as nickel electroplating and can be used as a substitute.

They do not take into account volume and amount

Teachers may now regard with some justification that the information in relation to toxicity, both chronic and acute MSDS is more relevant to industry where employees may be in contact with large amounts of material possibly as a dust or aerosol for the working day and throughout the year. This regular contact can seriously affect health.

The MSDS sheet does not take into account the tiny amounts of material used by teachers and students. However, we have already seen that the information on flammability, acute toxicity, corrosion and irritation to the eyes and skin is important. Please remember that corrosion is not about rusting but the destruction of body cells.

Using smaller amounts is even more important with flammable materials. Both in the USA and UK, people have been badly burned with liquids such as alcohols catching fire and there are large outcries to ban the chemicals used. In the UK a boy was badly burned on the chest (made worse with a rubber lined T-shirt underneath), leaning over a tea-light. Should we ban tea-lights, candles in restaurants, etc? It is constant vigilance and training on the part of the teacher and technician which matter and, more importantly, a realisation that the school-science staff need continual professional development, training etc. In the UK, senior management have a duty of care to monitor that science teachers are adhering to the rules (I don’t think they or anyone in Industry likes this, it but it is enshrined in our Health and Safety Law; it would be easier to simply blame and sack the teacher for an incident. ).

Teachers love teaching and they love to enthuse the students in a wonderful subject and they can easily push the boundaries too far by making a demonstration bigger. They see lecturers in lecture halls burst large balloons of hydrogen and oxygen, do “Liebig’s barking dog”, light large soap bubbles of methane or hydrogen (NOT LPG), in the air or their hands, breathe in helium and sulfur hexafluoride to affect the pitch of their voices. It all looks very easy but these lecturers rehearse and rehearse these demonstrations. (I call them edutainers!)The teacher cannot simply take these demonstrations into the classroom without a lot of research, training and practice. Balloons of hydrogen and oxygen are too loud for a small room and can cause deafness, Liebig’s barking dog can explode (as it did when he did it), burning gases on the hands can cause serious burns especially if LPG is used and inhaling gases is just bad practice in a school context as it can lead to bad habits by students.

They do not take into account the products of a chemical reaction

Seawater is about a 0.05M solution of sodium chloride. It is not classified as hazardous although with large exposure it can kill by ingestion of large volumes, it can be absorbed through the skin (ocean swimmers grease themselves) and breathing it in is pretty dangerous too! In the laboratory, I can put 2 carbon electrodes in sea water, connected to a low voltage supply, and generate chlorine, a highly toxic gas which can upset students with asthma. But there is no MSDS for chlorine as I do not buy the gas.

0.05 M sodium thiosulfate and 1M hydrochloric acid are not classified as hazardous but mix them together and sulfur dioxide is formed, a toxic gas. You do not have a MSDS for sulfur dioxide because you do not buy it. I cite both of these experiments because they have both caused students to be taken to hospital for checks on breathing and the inevitable call from safety officers and school managers as to why we are subjecting students to distress. These were activities set by examination boards for assessment. In both cases the teachers involved were not chemists by training and the lessons got out of hand. The exam had been set by experienced chemistry specialists who knew (and probably thought all teachers knew) about the hazards of the products.

It has taken 20 years for a reduced scale method developed by CLEAPSS to be finally accepted by one of our exam boards to be an accepted method of carrying out the reaction. The other essential part of this method is to pour the products of the reaction into a stop-bath of sodium carbonate solution which stops the reaction and neutralises the sulfur dioxide.

They are not risk assessments

Many articles on chemistry experiments cite hazards. The teacher should be more concerned about risk, the chances of an incident taking place and the potential severity/extent of harm that may be caused. Teachers of science need to demonstrate to senior management that they have reduced the possibility of an incident taking place and to ensure the use of the most comfortable personal protective equipment as the last resort. They can show this by including the method and relevant control measures in their schemes of work (SOW). As well as columns in SOW to please educational inspectors (e.g., learning objectives), there needs to be a column which shows that the teacher understands the possible risks from an activity and has taken steps (control measures) to reduce them. Both teachers and senior management should be aware that risk cannot be totally eliminated. The important factor is not to make a recorded risk assessment a huge multi-page document which will end up stored in a filing cabinet and never read (teachers do not have the time), but a few simple sentences to remind yourself (you might only do this activity once a year) and to remind your other colleagues who may take a lessons in chemistry. Lowering the concentration of a solution to a level which still illustrates what you are trying to show and has the smaller number of hazard statements is one way of showing that you applying risk assessments (hazard analysis). Teachers can add 0.4M sodium hydroxide solution to 0.1M copper(II) sulfate(VI) solution and still obtain a beautiful precipitate, instead of using 1M solutions which are far more hazardous for students to use. I can reduce the risks further by placing drops of these reagents on a plastic sheet.

If a teacher makes an improvement in safety, the SOW can be easily altered. The teachers’ risk assessment needs to look at how the chemicals are presented to students so this improvement on classroom management, is a part of the risk assessment.

It is important to focus on the relevant risks. In the last few years, boron compounds, used in producing green flames with methanol, have been given a hazard waning that they can cause harm to the unborn child. I have had teachers on the phone worried sick that they have used boric acid when they themselves or the students are of child bearing age. The fact that methanol is very flammable, as highlighted in a recent report by the Chemical Safety Bureau of serious fires in schools, and acutely toxic is never considered as the main risk. After all, it can be bought in Car shops in the USA so it must be safe. No!

You need training in how to use them

The teacher may be involved with over 400 chemicals in the year used in small amounts, for a few minutes and perhaps once a year. The industrial worker may be involved with 2 chemicals used in tonnes and litres (gallons) for the whole working year. The chemistry teacher might carry out 400 single operations with hazards in the year. The industrial worker might carry out only 2 hazardous operations but they are repeated daily and all through the year. Both situations have their dangers in complacency.

It often comes as a surprise to both teachers and educational managers that hazard analysis (https://www.osha.gov/Publications/osha3071.html) or Risk Assessment is important for any work with hazardous chemicals with the MAIN findings recorded. Fig 4 is taken from the UK HSE website.

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Figure 4: From the UK HSE Website

Very little quality training in safety is really offered in teacher training. The problem with safety training is that it can, in the hands of some, be a frightening list of ‘don’t do this’ and ‘don’t do that’. It can sometimes be over-emotive and worst of all, patronising. Safety training works best when it shows how procedures should be carried out and then by monitoring in a sensitive manner. This is best done by experienced practitioners (often retired), ideally with the blessing of relevant advisory bodies and subject institutions. A local Health and Safety Officer from the Armed Forces, an expert in Heavy Lifting and grave digging and, dare I say it, large-scale chemistry engineering or a recent graduate in science is not always the right person to deliver this training to teachers of chemistry.

Bob Worley FRCS, MSc, BSc (semi-retired advisor for Chemistry at CLEAPSS, UK)

Cellulose nitrate (also known as nitrocellulose or guncotton) is a very flammable substance that is formed by reacting cellulose (also known as dietary fiber) with a mixture of concentrated nitric and sulfuric acids:

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Figure 1:  Cellulose(polymer on top) reacts with a mixture of nitric acid in the presence of sulfuric acid to form cellulose nitrate (polymer on bottom).

Cellulose is a polymer of C₆H₁₀O₅ units.  In the formation of cellulose nitrate, each C₆H₁₀O₅ monomer is converted to a C₆H₇O₁₁N₃ unit.  Notice the high proportion of oxygen in cellulose nitrate.  Because of its high oxygen content this substance easily decomposes, releasing a lot of energy in the process: 

2 C₆H₇O₁₁N₃==> 9 CO + 3CO₂ + 7 H₂O + 3 N₂

You can see some experiments with cellulose nitrate in the video below.

This remarkable substance was discovered by Christian Friedrich Schönbein¹.  He also made several other contributions to chemistry, including the discovery of ozone.

Schönbein discovered cellulose nitrate by accident while experimenting in his kitchen, which according to some accounts was prohibited by his wife².     

During one set of experiments, Schönbein accidentally dropped a mixture of sulfuric and nitric acids on the kitchen floor.  He quickly cleaned up the spill with his wife’s cotton apron and hung it over the oven to dry (by the way, cotton is composed of about 90% cellulose).  Upon drying, the apron spontaneously burst into flame.  It is my guess is that Schönbein was banned from experimenting in the kitchen AFTER this particular incident!  (I can speculate with some authority on this matter, given that my own wife often frowns upon my at-home experiments).

The decomposition of cellulose nitrate is a great demonstration to perform in a chemistry classroom.  You can prepare cellulose nitrate on your own.  A good recipe is here (but please do not attempt this in your kitchen).  If you don’t have the time to carry out this procedure (or would rather not work with concentrated nitric and sulfuric acids), you can use ping pong balls as a convenient alternative.  Ping pong balls burn very well because they are partly composed of cellulose nitrate³:

Celluloid is a mixture of cellulose nitrate and camphor.  Celluloid was once used to make many objects such as combs, dolls, and other such figurines^3,4.  It is generally considered to be the first thermoplastic.      

With the ubiquitous use of synthetic plastics today, the use of celluloid as a plastic has been essentially phased out.  But celluloid is still used to make ping pong balls and guitar picks.  Be careful, though.  If you attempt to buy guitar picks as a source of cellulose nitrate for burning, make certain they are made of celluloid.  This is because the celluloid in guitar picks has begun to be replaced by different plastics.  Indeed, recent patent reports how to make celluloid-free ping pong balls that are not as flammable as the celluloid-type⁵.  As a result, you might want to stock up on ping pong balls if you plan on using them in your chemistry classroom for some time to come! 

1.  http://pubs.acs.org/doi/abs/10.1021/ed006p432

2. http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100446575

3.  http://pubs.acs.org/doi/abs/10.1021/ed069p311

4.  http://cool.conservation-us.org/jaic/articles/jaic30-02-003.html

5.  http://www.google.com/patents/US8105183

"Mr. T, you should do a review session for us before our final exam using a Google Hangout."

And that one sentence from a student of mine pushed me to try something new. In my IB Chemistry classes, we are in finals week and my students wanted some review time. Given their varying schedules for the rest of their finals, this student suggested we try a Google Hangout one evening before their final exam. I really like to be accessible to my students - and I love trying new ideas - so this sounded great.

A few minutes before the prescribed time, I started a Google Hangout and sent the link out to my students via Twitter. More students wanted to join the Hangout than there was room, as it is restricted to 10 people that can participate directly. Luckily, one of my students suggested I broadcast the Hangout to YouTube and the rest of the students could watch the review session and submit questions through Twitter. We ended up spending just over an hour together, with me answering student questions the entire time. It went well enough that students requested a second review session the next evening.

The mechanics of the Hangout were a bit finicky, as it took some time to figure out all of the controls available. The most valuable control for my Hangout was the ScreenShare. Using AirServer, I was able to show my iPad on the Google Hangout and use the Notability app to write out worked solutions to some of the calculation problems. In the example shown in the second photo below, I'm working out the solution to part of a limiting reagent problem.  I also brought up a few documents - like the IB Chemistry Data Booklet - to remind students areas of the data booklet they should be familiar with before their final.

And YouTube even records the Hangout. My review session has 75 views. Given that I have 61 IB Chemistry students, I figure that's a pretty good number. I certainly didn't have 100% participation, as it was an optional event and my schedule didn't necessarily match everybody. However, the option for students to come back to the Hangout and view it later is pretty cool in my book.

If you're going to try something of this sort, I'd recommend giving it a practice run first. I had a second review session the following night on a different laptop and it provided quite a few technical issues. So to grab a few screenshots to share, I started a new Hangout and noticed that things went a bit more smoothly.

I'm not suggesting that we all need to give up evening time for our students. I have a family that enjoys me being around and not stuck to my laptop working with my students. So I certainly won't be doing this every week. However, before a big final exam, or an external exam like AP or IB, I can see using this technique again. With 61 students spread throughout my IB classes, they can't all fit in my classroom for a review session. But they can all join the review session online!

Below are a few images to show you some of the nuts and bolts of the process.

How do you connect with your students outside of the classroom? 

First, the image below shows the Hangout screen that I was controlling. On the left are a number of settings, including ScreenShare. Students can also submit questions through the Chat feature. On the bottom right, I can select "Links" and provide my students with a link to the Hangout (limited to 10 students) and the YouTube livestream.

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The second image shows the Google Hangout screen while I had the iPad connected to my laptop. I run a second monitor on my laptop, so the main screen had my iPad connected with AirServer, while the extra monitor allowed me to follow the chat and check Twitter for questions while I was working.

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Happy December ChemEdX community! On December 2, 2014 I attended the second of three workshops on NGSS (Next Generation Science Standards) through our local ISD (in Kalamazoo County it is known as KRESA). This second workshop was much better than the first and allowed for brainstorming and problem solving on the teachers’ part as we worked together to craft and revise lab activities that would integrate the STEM components of NGSS, specifically the engineering components.

A major contention of the teachers present was how to best integrate these principles without increasing our budgets. Remember from my last post that NGSS is a set of standards, guidelines if you will. NGSS is not a curriculum. So, again, the real challenge here is how to integrate and modify existing activities so that they include components of the 8 Science and Engineering Practices in the NGSS (think...more engineering).

The 8 Science and Engineering Practices in the NGSS are:

Practice 1: Asking Questions and Defining Problems

Practice 2: Developing and Using Models

Practice 3: Planning and Carrying Out Investigations

Practice 4: Analyzing and Interpreting Data

Practice 5: Using Mathematical and Computational Thinking

Practice 6: Constructing and Designing Solutions

Practice 7: Engaging in Argument from Evidence

Practice 8: Obtaining, Evaluating, and Communicating Information

Some of you may be wondering how these practices are any different from simply doing inquiry-based labs. It isn’t much different, I don’t think. However, the above practices allow us to be more intentional with our students and help them to develop the necessary problem solving and critical thinking skills that we sometimes feel they lack.

As I mentioned above, one of the purposes of this past workshop was for teachers to bring an activity and modify it with the intention of integrating an engineering component along with focusing in on one or more of the 8 Science and Engineering Practices in the NGSS. I will post my activity in a subsequent post. My aim for this post, besides updating the ChemEdX community about my “adventures” with NGSS, is to share how I went about modifying my lab activity.

One of the handouts I received about this concept was an excerpt from a presentation done by Cheryll Adams (Ball State University), Alicia Cotabish (University of Central Arkansas), and Debbie Dailey (University of Central Arkansas) at the NAGC 61st Annual Convention and Exhibition (November 14, 2014). The title of the presentation was “Differentiating the Next Generation Science Standards at the Middle and High School Levels.” Particularly noteworthy was their inclusion of Douglas Llewellyn’s work (I think - reference isn’t clear) on modifying a traditional lab into an inquiry investigation.

The following table summarizes that information.

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Clik here to view.

To start, I chose a straightforward chemical reactions lab where students would follow the procedure, record qualitative observations, and determine what evidence there was for a chemical reaction taking place. My modifications included changing the initial research question and adding a follow up inquiry question at the end. The follow up question at the end required students to make a new hypothesis based on recent data, design an experiment to test their hypothesis and form conclusions, and, lastly, create drawings/models of what was taking place throughout the experimental process.

This inquiry approach took up most of 2 class periods and got students thinking about what was happening and whether or not their hypotheses (and preconceived notions) held any merit. As stated earlier, I will be posting the revised lab activity - so look out for it.

In a recent post, I indicated that I would make available the Chemical Reactions lab that I modified to meet NGSS guidelines. Enjoy!

Celebrating the International Year of Crystallography

The December 2014 issue of the Journal of Chemical Education is now available online to subscribers. The December issue includes content on: crystallography, assessment, career development for undergraduates, problem solving in organic chemistry, and teaching physical chemistry. This latest issue of JCE plus the content of all past issues, volumes 1 through 91, are available.

Editorial

Norbert Pienta, Editor-in-Chief, reviews and highlights content in Volume 91 (2014) of the Journal of Chemical Education.

Crystals and Crystallography

Cover

The International Year of Crystallography highlights the role that crystallography and structural analysis have played in many fields, including chemistry, physics, biology, and mineralogy, and throughout 2014 and beyond, the crystallographic community has organized events to engage the public in understanding crystallography and its importance. The cover features a selection of competition-winning crystals of copper sulfate pentahydrate grown by students as described in Celebrating the International Year of Crystallography with a Wisconsin High School Crystal Growing Competition by Ilia A. Guzei. Offering a historical perspective for understanding crystallography and its importance, Simona Galli discusses the fundamental contributions of X-ray crystallography made during the last century in chemistry, physics, and medicine in X-ray Crystallography: One Century of Nobel Prizes.

Exploring Gold Chemistry

The Late Start and Amazing Upswing in Gold Chemistry ~Helgard G. Raubenheimer and Hubert Schmidbaur

Understanding Structure

Exploring Electrochromics: A Series of Eye-Catching Experiments To Introduce Students to Multidisciplinary Research ~Leo J. Small, Steven Wolf, and Erik D. Spoerke

Illusions of Space: Charting Three Dimensions ~Leslie Glasser

An Inquiry-Based Learning Approach to the Introduction of the Improper Rotation–Reflection Operation, Sn ~John P. Graham

Reform in General Chemistry

Investigating the Longitudinal Impact of a Successful Reform in General Chemistry on Student Enrollment and Academic Performance ~Scott E. Lewis

Assessment

The Testing Effect: An Intervention on Behalf of Low-Skilled Comprehenders in General Chemistry ~ Daniel T. Pyburn, Samuel Pazicni, Victor A. Benassi, and Elizabeth M. Tappin

Comparison of High School Dual-Enrollment and Traditional First-Term General/Organic/Biochemistry College Chemistry Class Outcomes ~Daniel R. Zuidema and Kevin J. Eames

Developing an Array Binary Code Assessment Rubric for Multiple-Choice Questions Using Item Arrays and Binary-Coded Responses ~Elizabeth K. Haro and Luis S. Haro

Using Errors To Teach through a Two-Staged, Structured Review: Peer-Reviewed Quizzes and “What’s Wrong With Me?” ~Brian P. Coppola and Jason K. Pontrello

Career Development for Undergraduates

A Three-Year Chemistry Seminar Program Focusing on Career Development Skills ~Valerie K. Tucci, Abby R. O’Connor, and Lynn M. Bradley

Embedding Graduate Attributes at the Inception of a Chemistry Major in a Bachelor of Science ~Sarah A.M. Windsor, Kerry Rutter, David B. McKay, and Noel Meyers

A Survey of Industrial Organic Chemists: Understanding the Chemical Industry’s Needs of Current Bachelor-Level Graduates ~Justin D. Fair, Elyse M. Kleist, and Dylan M. Stoy

Aligning the Undergraduate Organic Laboratory Experience with Professional Work: The Centrality of Reliable and Meaningful Data ~Peter J. Alaimo, Joseph M. Langenhan, and Ian T. Suydam

Problem Solving in Organic Chemistry

Synthesis–Spectroscopy Roadmap Problems: Discovering Organic Chemistry ~Laurie L. Kurth and Mark J. Kurth

Synthesis Road Map Problems in Organic Chemistry ~Chris P. Schaller, Kate J. Graham, and T. Nicholas Jones

An Introductory Organic Chemistry Review Homework Exercise: Deriving Potential Mechanisms for Glucose Ring Opening in Mutarotation ~Margaret Murdock, R. W. Holman, Tyler Slade, Shelley L. D. Clark, and Kenneth J. Rodnick

Teaching Physical Chemistry

KinChem: A Computational Resource for Teaching and Learning Chemical Kinetics ~José Nunes da Silva Júnior, Mary Anne Sousa Lima, Eduardo Henrique Silva Sousa, Francisco Serra Oliveira Alexandre, and Antonio José Melo Leite Júnior

Influence of the Solvent on the Thermal Back Reaction of One Spiropyran ~Jonathan Piard

Web-Based Job Submission Interface for the GAMESS Computational Chemistry Program ~M. J. Perri and S. H. Weber

Introduction to Classical Density Functional Theory by a Computational Experiment ~Guillaume Jeanmairet, Nicolas Levy, Maximilien Levesque, and Daniel Borgis

Introduction to Density Functional Theory: Calculations by Hand on the Helium Atom ~Kyle A. Baseden and Jesse W. Tye

Gaussian-Type Orbitals versus Slater-Type Orbitals: A Comparison ~Alexandre L. Magalhães

Spontaneity and Equilibrium III: A History of Misinformation ~Lionel M. Raff

In the Laboratory

Physical Chemistry

Improved Method for Determining the Heat Capacity of Metals ~Roger Barth and Michael J. Moran

Thermodynamics Fundamental Equation of a “Non-Ideal” Rubber Band from Experiments ~Hernán A. Ritacco, Juan C. Fortunatti, Walter Devoto, Eugenio Fernández-Miconi, Claudia Dominguez, and Miguel D. Sanchez

A Stopped-Flow Kinetics Experiment for the Physical Chemistry Laboratory Using Noncorrosive Reagents ~Richard V. Prigodich

Computational Chemistry

Computational Chemistry in the Undergraduate Laboratory: A Mechanistic Study of the Wittig Reaction ~Birgit Albrecht

Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene ~E. Ramsey Frey, Andrzej Sygula, and Nathan I. Hammer

Investigating Hydrogen Bonding in Phenol Using Infrared Spectroscopy and Computational Chemistry ~Anna M. Fedor and Megan J. Toda

Biochemistry

Kinase Activity Studied in Living Cells Using an Immunoassay ~Aljoša Bavec

Protein Quantification by Elemental Mass Spectrometry: An Experiment for Graduate Students ~Gunnar Schwarz, Stefanie Ickert, Nina Wegner, Andreas Nehring, Sebastian Beck, Ruediger Tiemann, and Michael W. Linscheid

Ion Exchange and Thin Layer Chromatographic Separation and Identification of Amino Acids in a Mixture: An Experiment for General Chemistry and Biotechnology Laboratories ~Linda S. Brunauer, Katelyn E. Caslavka, and Karinne Van Groningen

Building Instrumentation

From Voltage to Absorbance and Chemical Kinetics Using a Homemade Colorimeter ~Jorge Delgado, Iraís A. Quintero-Ortega, and Arturo Vega-Gonzalez

Assembly of a Vacuum Chamber: A Hands-On Approach To Introduce Mass Spectrometry ~Guillaume Bussière, Robin Stoodley, Kano Yajima, Abhimanyu Bagai, Aleksandra K. Popowich, and Nicholas E. Matthews

It’s a Jolly Holiday with 91 Years of Chemistry

This issue marks 91 years of providing useful materials for chemical educators. We wish you a happy holiday season filled with opportunities to enjoy chemistry, such as reading some of the Chemical Adventures of Sherlock Holmes, doing a demonstration of a clock reaction demonstration involving red and green colors, experiencing the senses of the season, or writing holiday greetings using chromatography.

With 91 volumes of the Journal of Chemical Education to explore, you will always find something useful—including all of the articles mentioned above, and many more, in the Journal of Chemical Education. Articles that are edited and published online ahead of print (ASAP—As Soon As Publishable) are also available.

By Tom Kuntzleman and Randy Wildman

The “bucket launch” is a fantastic experiment you can do if you have access to liquid nitrogen.  See the video below:

Depending upon conditions, we have observed the bucket to launch anywhere from 80 to 160 feet high.  For reference, the clock tower you see in the video is 80 feet tall.   

To conduct this experiment, I filled a plastic 2 liter soda bottle about one-third full with liquid nitrogen and sealed the bottle.  The sealed bottle was then placed upright in a pan of room temperature water that was placed on a hard surface.  After placing a 5-gallon plastic pail over the soda bottle and pan of water, I quickly moved far away to watch the results (CAUTION:  If you plan on doing this experiment on your own, please read the hazards section at the end of this blog post).

Some of the liquid nitrogen in the bottle vaporized as it gained energy from the water.  This caused the pressure in the bottle to go up as a result of the buildup of nitrogen gas.  The pressure increased to the point where the bottle could no longer contain the gas, and the bottle exploded.  (Several online reports indicate that soda bottles fail under pressures of about 10 atmospheres¹).  The energy released in the explosion was sufficient to launch the 5 gallon pail high into the air.

The experiment presents a rich assortment of quantitative analysis possibilities because so many of the conditions inside the bottle just before it bursts are known or are able to be inferred. The pressure is the bursting point of the bottle, the temperature is the boiling point of the liquid nitrogen at the bursting pressure, and the volume is 2 liters minus the liquid volume. In fact, the only parameter we do not know is n, the amount of liquid nitrogen that has vaporized. (It was a fellow ChemEdX user, Roy Jensen, who pointed out that this parameter, n, needs to be calculated or determined, correcting an error I made in a previous description of this experiment). At the very least, the system gives us a great opportunity to test the ideal gas law, which is done below. Also, the system poses interesting questions. One question is just how much energy is released from the expansion of the cold, compressed nitrogen vapor, and how does it compare to the energy needed to lift the bucket so spectacularly? I, along with another ChemEdX user, Randy Wildman, give a rough calculation of this as well.  The calculations are arranged according to student/class level.

If you have any suggestions for improvements to the following analysis, we’d love to hear from you.  There are still several questions we are wondering about regarding this experiment.

1.  Analysis in High School / Introductory / General Chemistry:

First, let’s look at how the ideal gas law and the concept of vapor pressure can be used in conjunction with this experiment.  The ideal gas law is:

             Image may be NSFW.
Clik here to view.      Equation 1

where P is pressure, V is volume, n is moles of gas, R is the gas constant

(0.0821 L atm mol^-1 K^-1) and T is temperature.  Equation 1 can be used to estimate the number of moles of gas contained in the pop bottle just prior to explosion.  To do so, we need to estimate P, V and T just prior to explosion.  Based on the online reports of the pressure required to cause the bottle to explode, we set P = 10 atm.  To estimate the temperature, we examine the vapor pressure curve for nitrogen (a good one can be found here).

From the vapor pressure curve, it can be seen that nitrogen boils at about 105 K at a pressure of 10 atm.  Because the 2 L bottle is one-third full of liquid nitrogen, we can roughly estimate that 1.33 L of headspace is left over for gas buildup.  Insertion of these values of P, V and T into Equation 1 yields an estimate of 1.54 moles of nitrogen gas buildup prior to explosion.

2.  Analysis in General Chemistry:

For students of general chemistry, a slightly more rigorous analysis may be conducted to yield a better estimate for the gas volume.  This is done by considering that the gas volume inside the pop bottle increases in volume as the liquid nitrogen evaporates to form gaseous nitrogen (Figure 1). 

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Clik here to view.

Figure 1:  Change in N₂ (g) volume as liquid nitrogen evaporates inside a pop bottle.  V₀ is represented by the grey area.  V is represented by the grey area + the blue area above the dotted line.

Therefore, a better estimate of the gas volume in the headspace is:

Image may be NSFW.
Clik here to view.               Equation 2

Where V₀ is the headspace volume after just filling the bottle (1.33 L), n is the number of moles of nitrogen gas that have formed, M is the molar mass of nitrogen (28.0 g mol^-1) and D is the density of liquid nitrogen at 10 atm and 105 K (665 g L^-1).  Insertion of Equation 2 into Equation 1 yields:

Image may be NSFW.
Clik here to view.    Equation 3

Solving Equation 3 for n yields:

Image may be NSFW.
Clik here to view.            Equation 4

Substitution of the appropriate values into Equation 4 allows for the estimate that 1.62 moles (compared to 1.54 moles in the simple analysis) of gas build up in the bottle just prior to explosion.  Using 1.62 moles, it can be noted (Equation 2) that the gas volume increases from 1.33 L to 1.40 L during the expansion. 

3.  Analysis in General / Physical Chemistry

 We can take this analysis a bit further.  Recall that the ideal gas law (Equation 1) assumes that gas molecules neither attract nor repel one another.  Furthermore, the ideal gas law assumes that gas molecules do not have volume.  These are not good assumptions when gases are at low temperature and high pressure.  However, in this experiment, the pressure is quite high and the temperature is quite low!  To account for deviations from ideality, a correction factor called the compressibility factor (Z) is added to the ideal gas law:

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Clik here to view.                 Equation 5

Values of Z have been tabulated for nitrogen at several temperatures and pressures².  Values of Z for any specific temperature and pressure can be interpolated from the tabulated values; Z = 0.792 at its boiling point 10 atm pressure³.  Substitution of Equation 2 into Equation 5 yields:

Image may be NSFW.
Clik here to view.           Equation 6

Solving Equation 6 for n yields:

Image may be NSFW.
Clik here to view.                   Equation 7

Insertion of appropriate values into Equation 7 yields n = 2.08 moles of gas buildup.  This substantial increase from the ideal gas analysis indicates that the nitrogen gas is not behaving ideally prior to explosion. 

 4.  Analysis in Physical Chemistry

 The van der Waals equation of state (Equation 8) provides a more accurate description of the behavior of gases than the ideal gas law:

Image may be NSFW.
Clik here to view.               Equation 8

In the equation above, a and b are correction factors that take into account molecular volumes (b) and intermolecular forces (a).  For N₂, a = 1.41 atm L² mol^-2 and b = 0.0391 L mol^-1.  Equation 8 can be rearranged to give a polynomial in n:

Image may be NSFW.
Clik here to view.               Equation 9

At this point, we could substitute Equation 2 into Equation 9 (in fact, this might be a good exercise for students of Physical Chemistry).  For simplicity, we estimate the gaseous volume to be 1.42 L using Equation 2 and n = 2.08 (which we found in section 3, above).  After substitution of appropriate experimental parameters into Equation 9, the moles of gas contained in the bottle is determined to be 1.99 by finding the roots of Equation 9.  Of note the gaseous volume calculated using Equation 2 is 1.41 L if n = 1.99.  This result is in good agreement with the analysis using Equation 7.   

5.  Analysis using Physics

Now that we have a good estimate of the number of moles of gas involved in the explosion, we can gain insight into how high the bucket can be launched.  In other words, if nitrogen gas trapped inside a pop bottle at 10 atm suddenly explodes, how high can the bucket be launched if all of the energy from the explosion goes into launching the bucket?

The work (w) done by the gas on exploding can be calculated as pressure – volume (or P-V) work, which expressed in its differential form is:

Image may be NSFW.
Clik here to view.             Equation 10

Assuming ideal conditions throughout the expansion:

Image may be NSFW.
Clik here to view.                 Equation 11

We can assume that n and T remain constant throughout the explosion.  This might seem odd, given that rapidly expanding gases usually cool upon expansion and the temperature would thus be expected to drop.  But in this case, the gas is quite near its condensation point. So it is likely that once a small portion of the gas cools upon expansion, that portion would condense.  Upon condensing, the small portion would release energy as heat to the surrounding gas.  This could possibly keep the temperature constant in the surrounding gas.  If gas is condensing, then it might seem inadvisable to assume that n (the moles of gas) is constant throughout the process.  However, because the heat of vaporization of nitrogen (3500 J mol^-1) is so much bigger than the heat capacity of gaseous nitrogen (23 J mol^-1 K^-1), not much gas needs to condense in order to provide enough energy to maintain the temperature throughout expansion.  The simplifying assumptions of constant temperature and moles are by no means perfect, but they aren’t outlandish, either.  Using these assumptions, we can integrate both sides of Equation 11 as follows:

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Clik here to view.         Equation 12

To yield:

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Clik here to view.          Equation 13

Where V_I is the volume of the gas just after explosion but prior to any expansion and V_F = nRT/P_F, where P_F = atmospheric pressure (1 atm).  Using n = 2.08 mol, T = 105K, V_I = 1.4 L and V_F = nRT/P_F =  17.9 L, we find w = 4627 J. 

Some of this work is used to burst open the soda pop bottle, some of this work is used to allow the gas to expand against the surrounding atmosphere, and some of this work is used to launch the bucket.  Engineers that study damage done by gas explosions routinely estimate that half of the explosive energy is used to burst open the container holding the gas.  I’d guess that most engineers deal with gases enclosed in metal containers which almost certainly require more energy to break open than plastic.  So we’ll guess that 10%, or 463 J of energy is required to break open the pop bottle.  The work of expanding against the atmosphere is P-V work:

            Image may be NSFW.
Clik here to view.               Equation 14

P_atm = 1 atm and DV = 17.9 L – 1.4 L = 16.5 L, so Equation 14 predicts that 16.5 L-atm or 1672 J of work is required for gas expansion.  With 463 J required to burst the bottle and 1672 J required for gas expansion, 2492 J (4627 J – 1672 J – 463 J) = are left to launch the bucket.

Does this result make sense?  Well, the energy, E,  gained by a bucket of mass, m, launched to a height, h is:

Image may be NSFW.
Clik here to view.                    Equation 15

Where g = 9.81 ms^-2.  According to Equation 15, launching a 1.25 kg bucket (the mass of our bucket used) 80 feet (24.4 m) high would require 300 J of energy.  Therefore, about one-eighth (300 J/2492 J) of the energy available in the explosion is transferred to the bucket to launch it 80 feet high.

HAZARDS:  I describe here some useful tips if you plan on trying this experiment yourself.  Please know that all details required for a safe and successful launch have NOT been described herein.  If you try this experiment, you do so at your own risk.  The bucket needs to be liberally reinforced with duct tape.  Otherwise, the impact from the explosion will not launch the bucket in the air.  Rather, the bucket will shatter into many pieces.  After tightly sealing the bottle, STAND BACK.  Pieces of plastic from the exploded 2 L bottle can be thrown as far as 30 m.  If the bottle is not sealed properly, hissing noises can be heard as gas escapes from the bottle.  In the event the bottle is not sealed properly, DO NOT approach the assembly until you are certain that all of the gas has escaped. 

1.  For example, see https://www.youtube.com/watch?v=r3RP0trKgI0

2.  http://www.bnl.gov/magnets/staff/gupta/cryogenic-data-handbook/Section6.pdf

3.  http://www.peacesoftware.de/einigewerte/stickstoff_e.html  (When using this site, be certain to use the calculator designated for nitrogen in the saturated state).

Happy New Year!

With a new calendar year comes perpetual snow days and eventually a new semester. The main theme of my most recent posts have dealt with taking a new approach with labs. Specifically, I’ve wanted to add more high quality labs that incorporate components of NGSS. I will continue to modify my labs in 2015 and include more of the NGSS components as the new semester approaches.

For many, the beginning of a new year involves creating resolutions. And, hopefully not quitting them! Something that has been in the works for the last month on my end has been modifying the presentation and submission of lab reports for my upcoming Honors Chemistry 2 class. This class is a second semester honors chemistry course made up of primarily juniors. There will be a few 10th and 12th graders, along with one 8th grader that I had in Honors Chemistry 1 last year! It will be quite a diverse group. It is important to note that most of these students go on to take IB Chemistry, IB Biology, or both in their junior or senior year.

With this in mind, I sought out advice from a colleague at my school who teaches IB Chemistry. I also sought out advice from my Twitter PLN (namely @dragan, @ThomsonScience, and @OChemJulie; @CTay0604 also contributed). My goal was to devise the structure of the report based on the IB Chemistry lab syllabus and colleagues’ feedback in order to prepare students for IB-oriented lab reports. The primary consensus was to focus more on data analysis, calculations, error analysis, and extension questions rather than components that could result in increased plagiarism and academic dishonesty (such as materials, safety, experimental procedures/methods, etc.). A Google search also helped as I researched other high school lab report formats (Pascack Valley Regional High School District). Feel free to click here to view my proposed lab report format.

The second part of my post is to describe how I am changing the submission of lab reports. During this past/current semester, I utilized Google Classroom for the assignment and submission of all projects in my Computer Applications course. I have been very pleased with this format and wanted to include this component with the Honors Chemistry 2 lab reports. According to Google, Classroom is:

• “available to anyone with Google Apps for Education, a free suite of productivity tools including Gmail, Drive and Docs;
• Classroom is designed to help teachers create and collect assignments paperlessly, including time-saving features like the ability to automatically make a copy of a Google Document for each student;
• It also creates Drive folders for each assignment and for each student to help keep everyone organized;
• Students can keep track of what's due on the Assignments page and begin working with just a click; and,
• Teachers can quickly see who has or hasn't completed the work, and provide direct, real-time feedback and grades right in Classroom.”

Rather than collect every student’s lab report, read through each individual report, and make handwritten comments (which takes time), Google Classroom will permit me to quickly access lab reports digitally, leave comments in the Google Doc, and provide grades which can be imported to my school’s gradebook (or entered manually).

If you are interested in finding out more about Google Classroom, comment below. Or, check out https://classroom.google.com/. I should mention that this is not a product placement or testimonial for Google. Rather, it is a solution I’ve found helpful in how I teach and observe student work.

Here we are, starting another new semester! We call it the spring semester at our institution, but there is snow everywhere here! I am excited to report that I did use the activity Change You Can Believe In (gvsu.edu/targetinquiry) last semester on our first evening and I will be using it again tonight. It is such a beautiful way to begin our course. For starters, it gets the students talking to one another instead of me droning on about the syllabus and class expectations. (I do it in little pieces throughout the first week to keep it interesting.) It gets students thinking about patterns immediately. Students begin to think about atoms and molecules from the first day of class and using language like, "these bonds seem to be breaking." Wow!  Discussing particulate matter on the very first day! Using this activity also sets the tone for the entire semester. My students realize that although I am around and active in the classroom, I am not always the main focus. They begin to look to one another for support rather than always looking at me. They start to see that I refuse to give out answers, but instead will ask questions to point them in a certain direction and encourage them to think. Last semester we did not get to the second activity Chad Bridle wrote called The Only Constant is Change but I plan to do that activity in our first lab session tomorrow  I will let you know how it goes! Does anyone else have some favorite 1st day activities that really draw the students into chemistry?

The founders of the Hach company established the Hach Scientific Foundation in 1982. One of the programs that has emerged from this foundation is the High School Chemistry Grant Program. This grant is available to high school chemistry teachers. Teachers that have ideas to improve the teaching and learning of chemistry in their classrooms are encouraged to apply. Teachers are given up to $1500 for their ideas. The 2015 application cycle begins February 1st and runs until April 1.

“On the third day of Christmas, my mailman brought to me… three gardening catalogs.” Jumping the gun? Or marketing genius? The doldrums after the holiday were a perfect time for these pages with their promise of spring. Their arrival kicked off an evening of grand plans. Somewhere along the line, chemistry crept in.

We mapped out favorite seeds to fill our home garden. We also looked forward to the return of the weekly farmers’ market for an even wider selection to the bounty, even though its June start time is awhile down the road.

That night brought a flash as I was falling asleep. A flash of garden mixed with chemistry with community. Could the local farmers’ market be an opportunity to sow the seeds of science?

The market offers non-profit groups the chance to have their own booth for free alongside those selling fruits, vegetables, flowers, and more. What about a booth focused on science related to gardening and the outdoors? Both adults and children are typically at the market and might enjoy a short hands-on activity or demo. Then, a handout to take home as an encouragement to learn more.

First to mind was a recent inhabitant of our refrigerator—red cabbage. It would be easy to show how it and other natural products work as indicators, using JCE Classroom Activity #2 Anthocyanins: A Colorful Class of Compounds as a handout. The activity gives enough detail to try additional indicators at home to test household materials. What else? A quick runthrough of the list of JCE Classroom Activities yields more seeds of science, enough to share a new activity for multiple weeks. We could:

#78—Soil Testing: Dig In!
Take a closer look at soil along with testing its pH.

#60—Water Filtration
Use a water filtration column made of gravel, sand, and activated charcoal.

#22—Colors to Dye for: Preparation of Natural Dyes
Look at items to use as sources of natural dyes, like onion skins and blueberries. 

#30—Cabbage Patch Chemistry
Learn about the chemical fermentation of vegetables.

#36—Putting UV-Sensitive Beads to the Test
Use ultraviolet detecting beads to remind us about protecting our skin when we’re outside.

#17—Soup or Salad? Investigating the Action of Enzymes in Fruit on Gelatin
Explore what happens when certain fresh fruit is used with gelatin.

#50—Acid Raindrops Keep Fallin’ in My Lake
Consider how different solids in a lake can have an effect on its pH.

#53—Apple Fool! An Introduction to Artificial Flavors
Try to fool our taste buds in an attempt to recreate the flavor of cooked apples.

#86—Cooking Up Colors from Plants, Fabric, and Metal
Visit the flower garden as a source of dyes, with a twist provided by cast iron cookware.

Next up—how to make it happen, with funding for supplies and a possible source of volunteers. One idea is to write it up as an ACS ChemClub community activities grant application. I’ve been mulling over the idea of reactivating our homeschool group’s ChemClub now that a new crop of students is aging up into the high school years. Active ChemClubs can receive up to $300 to help them share chemistry in their communities. It might also be an idea for outreach through the new classical elementary school where I’ve been teaching science this school year. The students themselves could help with sharing the science. It’s a good time to start planting some seeds!

A New Year with a New Volume of Resources

The January 2015 issue marks the start of the 92nd volume of the Journal of Chemical Education and is now available online. This issue features colorful chemistry; using stories and writing to learn; demystifying chemistry literature; cost-effective activities and materials; experimenting with chromatography and natural products. The January issue will be available as a sample issue for the entire year, so the full text of all articles can be accessed without a subscription.  

Colorful Chemistry

Cover

In A Colorful Solubility Exercise for Organic Chemistry, Christopher R. Shugrue, Hans H. Mentzen, II, and Brian R. Linton describe a discovery chemistry laboratory for introductory organic chemistry students to investigate the concepts of polarity, miscibility, solubility, and density. The simple procedure takes advantage of the solubility of two colored dyes in a series of solvents or solvent mixtures.

Other articles in the issue that explore color and chemistry include:

A Guided Inquiry Liquid/Liquid Extractions Laboratory for Introductory Organic Chemistry ~ Margaret L. Raydo, Megan S. Church, Zane W. Taylor, Christopher E. Taylor, and Amy M. Danowitz

Chemistry under Your Skin? Experiments with Tattoo Inks for Secondary School Chemistry Students ~ Marc Stuckey and Ingo Eilks

Adsorption of a Textile Dye on Commercial Activated Carbon: A Simple Experiment To Explore the Role of Surface Chemistry and Ionic Strength ~ Angela Martins and Nelson Nunes

Introducing the Human Element in Chemistry by Synthesizing Blue Pigments and Creating Cyanotypes in a First-Year Chemistry Course ~ Olivier Morizot, Eric Audureau, Jean-Yves Briend, Gaetan Hagel, and Florence Boulc’h

Using Raman Spectroscopy and Surface-Enhanced Raman Scattering To Identify Colorants in Art: An Experiment for an Upper-Division Chemistry Laboratory ~ Hannah E. Mayhew, Kristen A. Frano, Shelley A. Svoboda, and Kristin L. Wustholz

Editorial & Commentary

Norbert Pienta, Editor-in-Chief, discusses Testing in a Traditional General Chemistry Course.

Vicente Talanquer examines Threshold Concepts in Chemistry: The Critical Role of Implicit Schemas and highlights five critical shifts in students’ implicit schemas that should be fostered to support mastery of major threshold concepts in chemistry.

Using Stories and Writing to Learn

Storytelling with Chemistry and Related Hands-On Activities: Informal Learning Experiences To Prevent “Chemophobia” and Promote Young Children’s Scientific Literacy ~ Carla Morais

“On Course” for Supporting Expanded Participation and Improving Scientific Reasoning in Undergraduate Thesis Writing ~ Jason E. Dowd, Christopher P. Roy, Robert J. Thompson, Jr., and Julie A. Reynolds

Using Wikis To Develop Collaborative Communities in an Environmental Chemistry Course ~ Laura E. Pence and Harry E. Pence

Creative Report Writing in Undergraduate Organic Chemistry Laboratory Inspires Nonmajors ~ Maged Henary, Eric A. Owens, and Joseph G. Tawney

Poster Presentations: Turning a Lab of the Week into a Culminating Experience ~ Jennifer L. Logan, Rosalynn Quiñones, and Deborah P. Sunderland

Demystifying Chemistry Literature

Demystifying the Chemistry Literature: Building Information Literacy in First-Year Chemistry Students through Student-Centered Learning and Experiment Design ~ Margaret Bruehl, Denise Pan, and Ignacio J. Ferrer-Vinent

Student-Led Engagement of Journal Article Authors in the Classroom Using Web-Based Videoconferencing ~ Brian J. Stockman

An Exercise To Coach Students on Literature Searching ~ Kate J. Graham, Chris P. Schaller, and T. Nicholas Jones

Cost-Effective Activities and Materials

Electrolysis of Water in the Secondary School Science Laboratory with Inexpensive Microfluidics ~ T. A. Davis, S. L. Athey, M. L. Vandevender, C. L. Crihfield, C. C. E. Kolanko, S. Shao, M. C. G. Ellington, J. K. Dicks, J. S. Carver, and L. A. Holland

Making a Low-Cost Soda Can Ethanol Burner for Out-of-Laboratory Flame Test Demonstrations and Experiments ~ Henson L. Lee Yu, Perfecto N. Domingo, Jr., Elliard Roswell S. Yanza, and Armando M. Guidote, Jr.

Low-Cost Magnetic Stirrer from Recycled Computer Parts with Optional Hot Plate ~ Armando M. Guidote, Jr., Giselle Mae M. Pacot, and Paul M. Cabacungan

Designing, Constructing, and Using an Inexpensive Electronic Buret ~ Tingting Cao, Qing Zhang, and Jonathan E. Thompson

Assembly of a Robust and Economical MnO₂-Based Reference Electrode~ Robert C. Massé and James B. Gerken

Coffee Stirrers and Drinking Straws as Disposable Spatulas ~ Morgan A. Turano, Cinzia Lobuono, and Louis J. Kirschenbaum

Design and Building of an Inexpensive and Sturdy Pipet Bulb Filler Port ~ Neil D. Danielson and Alex P. Danielson

Exploring Chromatography

Paper Chromatography and UV–Vis Spectroscopy To Characterize Anthocyanins and Investigate Antioxidant Properties in the Organic Teaching Laboratory~ Kelli R. Galloway, Stacey Lowery Bretz, and Michael Novak

“Supermarket Column Chromatography of Leaf Pigments” Revisited: Simple and Ecofriendly Separation of Plant Carotenoids, Chlorophylls, and Flavonoids from Green and Red Leaves ~ Alice M. Dias and Maria La Salete Ferreira

Normal and Reversed-Phase Thin Layer Chromatography of Green Leaf Extracts ~ Birte Johanne Sjursnes, Lise Kvittingen, and Rudolf Schmid

Natural Products Laboratories

Spectroscopic Determination of Triclosan Concentration in a Series of Antibacterial Soaps: A First-Year Undergraduate Laboratory Experiment ~ Graeme R. A. Wyllie

Purity Analysis of the Pharmaceuticals Naproxen and Propranolol: A Guided-Inquiry Laboratory Experiment in the Analytical Chemistry Laboratory ~ Sayo O. Fakayode

Gravimetric Analysis of Bismuth in Bismuth Subsalicylate Tablets: A Versatile Quantitative Experiment for Undergraduate Laboratories ~ Eric Davis, Ken Cheung, Steve Pauls, Jonathan Dick, Elijah Roth, Nicole Zalewski, Christopher Veldhuizen, and Joel Coeler

Determination of Calcium in Dietary Supplements: Statistical Comparison of Methods in the Analytical Laboratory ~ Sarah L. Garvey, Golbon Shahmohammadi, Derek R. McLain, and Mark L. Dietz

Extraction of Maltol from Fraser Fir: A Comparison of Microwave-Assisted Extraction and Conventional Heating Protocols for the Organic Chemistry Laboratory ~ Andrew S. Koch, Clio A. Chimento, Allison N. Berg, Farah D. Mughal, Jean-Paul Spencer, Douglas E. Hovland, Bessie Mbadugha, Allan K. Hovland, and Leah R. Eller

Operationally Simple Synthesis of N,N-Diethyl-3-methylbenzamide (DEET) Using COMU as a Coupling Reagent ~ Jonathan M. Withey and Andrea Bajic

Recruiting the Students To Fight Cancer: Total Synthesis of Goniothalamin ~ Fady Nahra and Olivier Riant

Research & Reform

Paying Attention to Gesture when Students Talk Chemistry: Interactional Resources for Responsive Teaching ~ Virginia J. Flood, François G. Amar, Ricardo Nemirovsky, Benedikt W. Harrer, Mitchell R. M. Bruce, and Michael C. Wittmann

Biochemistry Instructors’ Views toward Developing and Assessing Visual Literacy in Their Courses ~ Kimberly J. Linenberger and Thomas A. Holme

Impact of Guided-Inquiry-Based Instruction with a Writing and Reflection Emphasis on Chemistry Students’ Critical Thinking Abilities ~ Tanya Gupta, K. A. Burke, Akash Mehta, and Thomas J. Greenbowe

Targeting the Development of Content Knowledge and Scientific Reasoning: Reforming College-Level Chemistry for Nonscience Majors ~ Justin H. Carmel, Yasmin Jessa, and Ellen J. Yezierski

From the Archives: Opera and Shakespeare Meet Poison

In this issue, opera and Shakespeare take center stage:

Viewing Scenes of the History of Chemistry through the Opera Glass ~ João Paulo André

Bringing in the Bard: Shakespearean Plays as Context for Instrumental Analysis Projects ~ Kathryn D. Kloepper

Forensic ties to these topics in past issues include:

Opera and Poison: A Secret and Enjoyable Approach To Teaching and Learning Chemistry ~João Paulo André

O True Apothecary: How Forensic Science Helps Solve a Classic Crime ~ Amanda S. Harper-Leatherman and John R. Miecznikowski

There’s Always More to Explore

With over 90 volumes of the Journal of Chemical Education to explore, you will always find something useful—including all of the articles mentioned above, and many more, in the Journal of Chemical Education. Articles that are edited and published online ahead of print (ASAP—As Soon As Publishable) are also available.

Wow! Night one of the semester we did the activity Change You Can Believe In. It was my second time facilitating, so I did a much better job of directing students when they asked questions and it went much faster than last semester. I did still, as expected, have students that were frustrated. One student asked me point blank what the difference between physical and chemical changes is. I redirected her to the goal of the lab and she was willing to return to work with her group. There is a fine line between good frustration, and too much, and this student seemed to be at that perfect point. She was just frustrated enough to continue, but she was not overly discouraged. At the end of the evening, during our class discussion, students were beginning to hone in on the differences between chemical and physical changes. By the following evening, during our pre-lab discussion for The Only Thing Constant in Life is Change, students had an even better idea. Throughout the lab activities, I was impressed with the level of sophistication in their group converstations. They discussed things like whether or not a solid forming is evidence of a physical or chemical change, what is going on at the particulate level when water is boiling, what kind of change is it when a molecule is coming apart and reforming as a different molecule. In addition to these fantastic thoughts, students were learning other good lab skills like how to measure liquid in a graduated cylinder, what waste goes down the drain and what goes into a waste beaker, and what to do when measuring a solid and where to put the excess solid once you have used what you need for your activity. I didn't hear as many (I didn't hear any!) questions about when they would use these measuring skills like I do when we teach the skills indepently from a lab. Overall the students were able to determine the major differences between chemical and physical changes, how to do some basic lab techniques, and how to work as a group and to rely on one another for help, all of which will be helpful throughout this semester!

The Abstract Submission System for ChemEd 2015 is now open!

This biennial conference is the largest of its kind, bringing together dedicated educators involved in high school and introductory chemistry from across North America. Educators are immersed in a setting facilitating collaboration, support, the exchanging of ideas, and inspiration over a period of five days. Demonstrations, hands on labs, and workshops, and chemistry sessions are among other activities seeking to further develop teachers in the chemistry field. The conference has grown over the years and has ranged from 400-800 participants. 

The Abstract Submission System can be accessed through the webpage for the Chem Ed 2015 or go directly to the Abstract Submission System. 

To provide an opportunity to have as many people present as possible, only 3 presentations will be accepted for each lead presenter. There are 4 presentation types to choose from for each abstract submission: 1) Presentation; 2) Workshop; 3) Laboratory; 4) Computer-based Workshop. 

Separate applications are required for each abstract submitted. Titles should be entered in sentence case and be 150 characters or less (capitalize only the first letter of the title, any proper nouns or acronyms, and the first letter following a colon; do not end titles with a period). Abstracts should be 500 characters or less. Applicants need to choose a conference strand that the abstract fits and the audience the abstract is best suited for.

Abstracts must be submitted by February 27, 2015 and Registration opens March 1, 2015.

Inquires may be addressed to the general chair, Michelle Dean (

The CELA Scholarship is offered to help first-time attendees and presenters develop their knowledge and skills in chemical education, the ChemEd 2013 Conference committee has sponsored the 2015 ChemEd Legacy Award (CELA) Scholarship Program. The scholarship program will cover the registration fee for more than 12 first-time ChemEd attendees and more than 12 first-time speakers/presenters.  Travel and lodging are not covered under this scholarship program.

Goals of the CELA are:

• to enable individuals who for financial reasons may not be able to attend a ChemEd Conference.
• to increase participation by first-time attendees.
• to encourage and support first-time presenters. 

To Apply:
To apply for the CELA Scholarship please submit the online application. The deadline for submission is due by February 1, 2015. If you are applying as a first time presenter you must has also submitted your abstract by this date. Recipients will be advised by February 28, 2015 in time to register with anticipating online conference registration starting March 1, 2013.

Recently, I was introduced to Larry Sernyk who is engaged with implementation of the Chemical Educational Foundation (CEF) educational programs in Indiana. He shared with me some of the exciting programs CEF has created to help highlight the importance of Chemistry in our everyday lives.  CEF particularly targets the K-8 classroom and Larry provided the following  description for these programs which is excerpted from CEF’s website which I am happy to share with the ChemEdX community. 

CEF's currently offers three YBTC programs:

YBTC Essential Elements: YBTC Essential Elements is designed to assist K–8 educators—our “essential elements” in education—in teaching chemistry concepts through hands-on learning and connecting those concepts to students’ everyday lives. During an Essential Elements workshop, the instructor will lead educators through a full 5E learning cycle utilizing a lesson from the YBTC Activity Guides. The 5E model is a constructivist learning cycle focused on inquiry-based learning. Following the lesson, educators will have the opportunity to discuss the lesson further and ask questions. The workshop will then proceed with additional lessons from the Activity Guides. Visit the Essential Elements pagehttps://www.chemed.org/ybtc/essential/ for more information on the 5E learning cycle format and how to bring an Essential Elements workshop to the schools in your community! If you are interested in scheduling a workshop for your school or school district or participating in an open workshop, please contact essential.elements@chemed.org.

YBTC Activity Guides: The YBTC Activity Guides: Lesson Plans for Making Chemistry Fun offer a variety of exciting science lesson plans, enabling educators to bring hands-on learning to students, inside and outside of the classroom. The Activity Guides are divided according to grade level, one for grades K–4 and the other for grades 5–8. Together the Activity Guides contain almost 1,000 pages of educator-reviewed experiments, activity sheets, supplements, and a resource guide filled with safety information, and much more. The content of the guides aligns to the national framework established for the Next Generation Science Standards. The Fourth Edition Activity Guides are now available in a flash drive format for purchase or as downloadable PDF's for free! Check out the Activity Guide pagehttps://www.chemed.org/ybtc/guides/ to see how to download them.

 YBTC Challenge: The YBTC Challenge is a fun and interactive academic competition that engages grade 5–8 students in learning about important chemistry concepts, scientific discoveries, and laboratory safety. Challenge competitions are exciting events that take place across the country, encouraging the collaboration of industry members, schools, and community organizations, as together, they educate students about the value of science education and the role of chemistry in their everyday lives. The Challenge cycle culminates in the National Challenge in June, held in Philadelphia and organized by CEF. For more information, please visit the Challenge page https://www.chemed.org/ybtc/challenge/. If you are interested in participating or want more information, please contact challenge@chemed.org. Please note that school registration for the 2015Local Challenges closes January 31, 2015.

In my high school chemistry classes, I stress the use of units and the use of written chemical formulas to be represented properly.  It is important to me that when a student expresses the formula of a chemical either in their data or in a balanced equation that they represent it correctly.  With that in mind there is nothing I dislike more then seeing the lack of subscripts and superscripts in writing chemical formulas.

                        Cu(s) + 2AgNO3(aq) à Cu(NO3)2(aq) + 2Ag(s)

                            Cu(s) + 2Ag+(aq) à Cu2+(aq) + 2Ag(s)

With the use of a laptop or a desktop computer then the ability to use superscripts and subscripts as a formatting option isn’t typically an issue.  I am currently typing this up in MS Word and it’s easy to represent the above equation correctly with subscripts and superscripts.

                        Cu(s) + 2AgNO₃(aq)à Cu(NO₃)₂(aq) + 2Ag(s)

                            Cu(s) + 2Ag⁺(aq)à Cu²⁺(aq) + 2Ag(s)

However, in my classroom, I have a class set have a class set of iPads and so the use of subscripts and superscripts as a formatting option for my students requires creativity.  For example, in representing chemical formulas in Keynote for slide presentations, my students would have to use offset text boxes to represent subscripts or superscripts correctly. Some students would decrease the font size of the subscripts, which became a work around but they were still forced to create a separate text box for superscripts.  It does work, however it can be frustrating when students are so used to just simply clicking the superscript or subscript button and typing when using their laptop.

Recently, I was sent an email and was told to look at the app cymbols  https://itunes.apple.com/us/app/cymbol/id416714959?mt=8. It sells for $1.99 in the app store and is described as the following:

Cymbol, an iPad app providing fast, easy access to symbols, special characters, and scripts used in scholarly, business, and legal content, is now available from PhoneApp.com. Choose from special characters that are an adjunct available in addition to the iPad’s onscreen keyboard.   App store description

I have worked with the cymbol app now on several occasions and this seems to be a great fix. Besides the business symbols and several math symbols, the direct access to numerical superscript and subscript buttons has been quite beneficial. I shared the app with several of my high students and they were quite pleased with its capability and enjoyed being able to tweet a correctly written chemical formula complete with subscripts from within the app. The app works directly with several other apps and also works nicely by simply copying and pasting correctly without changing the formatting of the text. 

There is a video explaination. https://www.youtube.com/watch?v=nO0LrRTztEo.