ShareChanging Matter - Getting Warmer
Whenever a chemical change occurs, there are often changes in the physical properties of the substance that undergoes the change. Remember how different a fried egg looks from the raw egg? In this activity, you are going to test the temperature and see how this physical property changes as a result of chemical change.
Materials:
- 500 ml. beaker
- Thermometer
- 2 g. quick rising dry yeast
- 50 ml. 3% hydrogen peroxide
- Spoon
- Pen or pencil
- Paper
Procedure:
- Measure the room temperature using the thermometer.
- Place the thermometer in the beaker (you may need to hold it carefully
to keep it from falling over.)
- Make sure you can read the temperature easily.
- Pour the hydrogen peroxide into the beaker.
- Make sure that the temperature shown on the thermometer is stable, then record the temperature.
- Quickly use the spoon to stir the yeast into the hydrogen peroxide.
- Observe what happens for five minutes (make sure to record your observations.)
- Make sure that you feel the lower sections of the beaker.
- Take the temperature of the mixture.
Sample Data Table:
| Room Temperature: | |
| Hydrogen Peroxide Temperature: | |
| Observations: | |
| Mixture Temperature: |
Safety concerns: 
Be
sure to follow all glassware,
and chemical safety rules
that are specified by your teacher in all general laboratory experiences.
As with all science lab activities, the most important safety rule is to follow all teacher directions.
Analysis:
- What evidence did you observe that a chemical reaction had taken place?
- In what way did the temperature change?
- Which chemical changes did you observe?
- Which physical properties changed as a result of this experiment?
- How do you know that this was a chemical reaction and not the result of the yeast just growing and reproducing?
