In a recent post, I indicated that I would make available the Chemical Reactions lab that I modified to meet NGSS guidelines. Enjoy!
Concepts:
In this lab, students will address the concepts of chemical reactions, evidence for a chemical reaction, and devising hypotheses and experimental trials.
Time required:
2 53-minute class periods (about 2/3 of each class were used).
Materials:
- 1 baggie with zip seal
- 1 plastic spoon
- 1 10-mL of 25-mL graduated cylinder
- 1 small container/canister
- 1 plastic spoonful of sodium bicarbonate (baking soda)
- 2 plastic spoonfuls of calcium chloride (road salt)
Optional materials
- Digital balance
- Infrared thermometer
Background:
Research Question: How can you determine whether or not a chemical reaction takes place?
Background Knowledge:
- When a chemical reaction occurs, the products that form have different properties than the initial materials.
- Evidence of a chemical reaction.
- Endothermic and exothermic reactions.
Procedure:
Procedure:
- Recall the solubility data about sodium bicarbonate and calcium chloride. Indicate whether each is soluble or insoluble.
- Observe what the sodium bicarbonate looks like and record the data in your table.
- Place 1 tsp of the sodium bicarbonate in the plastic bag.
- Observe what the calcium chloride looks like and record the data in your table.
- Place 2 tsp of calcium chloride into the plastic bag.
- Observe if anything happens.
- Use a graduated cylinder to measure 10 mL of water and pour the water into the small container that was provided.
- Carefully set the water-filled container into the bag without spilling. Zip the bag closed while carefully removing air from the bag.
- Tip the container in the bag and record your observations.
Questions:
Data Analysis:
- Did a chemical reaction take place? How do you know?
- Draw a model for what you perceive to be happening before and after mixing the substances with water.
- Assuming that a chemical reaction did take place, was the reaction dependent on the presence of sodium bicarbonate, calcium chloride, or both? Create a hypothesis and devise an experiment to test your hypothesis. Then do your experiment, record data and observations, and develop a conclusion based on your results. Draw another set of models that demonstrate what is happening according to your hypothesis and results.
Preparation:
Gather all materials needed and walk students through lab expectations before going into the lab.
Attribution:
Dan Meyers
Chemistry Teacher, Portage Central High School, Portage, MI 49002
ChemEdX Contributor
Student Document:
