Great Heat Mystery

Purpose: Observe what happens when you combine calcium chloride (CaCl2), sodium bicarbonate (NaHCO3), phenol red and water?

Materials goggles chemical-resistant gloves100 mL graduated cylinder 80 mL water3.6g CaCl2 3.6g NaHCO3phenol redeyedroppercups (more than 60 mL) Ziploc® bags

Hypothesis: if you combine calcium chloride, sodium bicarbonate and water then _______________________

Safety: Goggles

Procedure Part 1: 3.6 g Sodium Bicarbonate3.6 g Calcium Chloride80 ml water6 ml universal indicator

Record color and temperature changes

Procedure Part 2:3.6 g Sodium Bicarbonate40 ml Water6 ml universal indicator3.6 g Calcium Chloride40 ml of waterTemperature

• Questions1. Was your hypothesis correct? Why or why not?2. What is the universal indicator used for?3. List the three things that indicated that there was a chemical reaction going onin this experiment.4. What type of chemical reaction was the mixing of the sodium bicarbonateand the calcium chloride?Endothermic or Exothermic (circle one)5. Use a Periodic Table to determine which elements are in each compound

• Use the balance to measure 3.6g of sodium bicarbonate into a cup.

• 2. Use the balance to measure 3.6g of calcium chloride into a cup.

• 3. Use the graduated cylinder to carefully measure 80 mL of water. Pour it into the Ziploc bag.

• (Be sure that no water spills)• 4. Add 2 eyedropper-full squirts of phenol red to the Ziploc

bag. Observe what occurs.• (Color changes from red to yellow or orange, gas forms, and

temperature changes (hot, then• cold). Students may be able to observe the formation of a new

substance, calcium carbonate,• which will precipitate out of the water solution.)

• 1. Use the balance to measure 3.6g of sodium bicarbonate into a cup.• 2. Use the balance to measure 3.6g of calcium chloride into a cup.• The Great Heat Mystery Lab• EDUCATOR MATERIALS• The Great Heat Mystery Lab• 2• EDUCATOR MATERIALS• 3. Carefully add the sodium bicarbonate to the bag. Then add 40 mL of water to the bag.• Finally, add 2 eyedropper-full squirts of phenol red to the bag. What happens to the• temperature? (If measuring with a thermometer, they may notice a 1-2 degree decrease• in temperature.)• 4. Use the graduated cylinder to carefully measure 40 mL of water. Pour it into the cup with• the calcium chloride. Add 2 eyedropper-full squirts of phenol red to the Ziploc bag. Observe• what occurs. (Cup contents turn hot.)• 5. Not all of the calcium chloride may be dissolved at this point. Add the calcium chloride• solution to the bag and seal it immediately. (Do not let the bag fully expand, or the bag may• burst and the contents would spill onto you or students.) What happens? (Gas is formed,• temperature changes (slightly colder) and color changes)• 6. Students may be able to observe the formation of a new precipitate, calcium carbonate.• Carefully swish the contents together to mix them. What do you feel?• 7. Dump the contents down the drain, rinse out the bag and dry it with paper towel.• 8. Wash your hands and answer the questions.