Chemical Change Lab Report

For this lab the knowledge to tell the difference between a chemical and physical changes was needed. To tell this the knowledge of the five signs of a chemical change was needed. These five signs are color change, odor change, production of bubbles/gas, production of heat/light, and the production of precipitate. Also prior to the lab one question was provided that needed to be answered. This question was what chemical must be present for a color change. The hypothesis that was provided to this question was If Phenol Red is add with the other chemicals then a color change will occur.

Methods: To begin the lab 40 mL of Phenol red were obtained in a beaker, and 40 mL of water were obtained in a separate beaker. Next one plastic baggie was

of Sodium bicarbonate (NaCHO3), and 5 mL of phenol red solution were all placed at separate location inside the baggie. Finally all the air was pushed out of the bag, the bag was sealed, and the contents were mixed thoroughly. Observation were then recorded and the bag was thrown away. This process was then repeated six more times using different combinations of chemicals. These combinations were: 2 tsp. NaHCO3 and 5 mL phenol red, 2 tsp. CaCl2 and 5 mL phenol red, 2 tsp. CaCl2 and 2 tsp NaHCO3 and 4 mL water, 2 tsp. NaHCO3 and 5 mL water, 2 tsp. CaCl2 and 5 mL water, 2 tsp. CaCl2 and 2 tsp. CaCl2.The question asked at the beginning of the lab was what chemical must be present for a color change to occur. My hypothesis was that if Phenol red was present then a color change would occur. This hypothesis was true because every reaction that had phenol red experienced a dramatic color change while the other reactions did not. In the lab it was also