Exothermic Lab

Standard: 3240-01 Students will observe and describe chemical and physical change

Objectives:
3240-0101 Differentiate between common chemical and physical changes.
3240-0102 Analyze factors that influence chemical and physical change.

INTENDED LEARNING OUTCOMES
1a. Make observations and measurements.
1d. Make estimations and predictions based on observations and current knowledge.
2d. Collect and record data using procedures designed to minimize error.
2e. Analyze data and draw warranted inferences.

250 ml beaker or similar sized cup
thermometer
1 tablespoon quick rising dry yeast or one small envelope dry quick acting yeast
1/4 cup 3% hydrogen peroxide ( what you get at the store)
spoon
pencil and paper

Procedure
1. Find the temperature on your thermometer (room temperature) and record.
2. Place the thermometer in the beaker.
3. In your beaker, stir peroxide and yeast together with a spoon.
4. Observe what happens over a period of time and record.
5. Feel the lower sides and bottom of the beaker. Record your findings.
6. Take the temperature of the mixture and record.

Analysis and Conclusions
1. Based on your observations, what do you think was being produced when the hydrogen peroxide and yeast were mixed ? Explain why your came up with your answer.
2. Why did the temperature change?
3. Are the results of this experiment an example of physical or chemical change or both? SUPPORT YOUR CONCLUSIONS WITH EVIDENCE FROM YOUR RESULTS. THINK HARD!!!!!!
4. Give at least one other example of an exothermic reaction you are familiar with. How do you know it is exothermic?

Teachers and students, you will be handling a chemical that is potentially dangerous. You will also be working with glassware. Be sure to keep all Chemical Safety Rules that are specified by your teacher and in all general laboratory experiences.

Adapted from 365 Simple Science Experiments by E. Richard Churchill, Louis V. Loeschnig, and Muriel Mandell