Procedure: Citric Acid and Baking Soda

1. Check this box when your safety goggles are on: ☐   DON’T TAKE THEM OFF.
2. Turn on the balance and make sure it says reads grams. Check this box when it reads zero grams: ☐
3. Put the clear plastic cup on the balance and press the On-Zero button. Check this box when it says zero grams: ☐
4. Add 10 grams of baking soda to the clear plastic cup. Add a little bit at a time until the balance reads 10 grams.
5. Measure out 40 mL of citric acid into your graduated cylinder.
6. Measure the temperature in degrees Celsius of the citric acid. Write this number on the Initial Temperature (t1) line on the next page.
7. Record your initial observations by answering question #1 on the next page.
8. Move the thermometer from the graduated cylinder to the plastic cup, and immediately pour the citric acid into the cup with the baking soda.
9. Swirl the cup.  This is a QUICK reaction.
10. Observe the reaction and record observations by answering question #1 on the next page.
11. Feel the flask to determine whether the reaction was endothermic or exothermic.
12. Record the final temperature on the Final Temperature (t2) line on the next page.

Procedure: Hydrochloric acid and aluminum foil

1. Check this box when your safety goggles AND gloves are on: ☐ DON’T TAKE THEM OFF.
2. Put the piece of aluminum foil into a clear plastic cup.
3. Measure out 20 mL of hydrochloric acid into a graduated cylinder.
4. Measure the temperature in degrees Celsius. Write this number on the Initial Temperature (t1) line below.
5. Record your initial observations by answering question #1 on the next page.
6. Add 20 mL of hydrochloric acid to the cup.
7. Swirl the cup.  This is a SLOW reaction.  It may take several minutes before anything happens. Record observations by answering question #1 on the next page.
8. Feel the flask to determine whether the reaction was endothermic or exothermic.
9. Record the final temperature on the Final Temperature (t2) line below.