Take Home Lab #5

Take Home Lab #5:  Dissolving Energy

Question: When you dissolve household chemicals is it exothermic or endothermic?

Safety: Clean up any spills immediately. Do not consume any of the chemicals. Wash out cups well after mixing chemicals.

Materials: Cup, room temperature water, salt, borax, powdered “ultra” laundry detergent, baking soda, thermometer

Procedure: In this investigation, you are going to dissolve different common household chemicals to see if these reactions are exothermic or endothermic changes.

1. Pour ¼ cup of water in a cup. Measure the initial temperature and record in your data table.

2. Add 2 tablespoons of baking soda to the water. Mix to dissolve and find the new temperature and record in your data table.

3. Wash out the cup and start step #1 again with a clean cup of water. Record the temperature

4. Add 2 tablespoons of salt to the water and stir to dissolve, measure the temperature and record to data table.

5. Repeat these steps with “ultra” powder laundry detergent and borax.

Data Table:

Substance:	Initial temperature of water:	Final temperature of mixture:
Baking soda
Salt
“Ultra” Laundry
Borax

               

Post-Lab Questions:

1. Identify which of the experiments were exothermic and endothermic.

2. What is your evidence that the reactions were exothermic and endothermic, how do you know?

3. Make two models to show what occurred in the exothermic reaction and endothermic reaction.

4. Calculate the amount of energy released or absorbed when water and baking soda were mixed. Use the formula Q=s∙m∙DT. (Where the mass of the water is 30g, s for water is 4.18 J/g∙C and your information from your data table.

5. Calculate the amount of energy released or absorbed when water and laundry detergent were mixed. Use the same formula and information from the question above.