Evidence For A Chemical Reaction

Furst, J-N Chemistry, D Block Lab Activity: Evidence for a Chemical Reaction Station 1: We got 5 ml of sodium hydroxide in a beaker, we measured its temperature which was 23c, and we measured its ph level which was 14. Then we poured 5ml of hydrochloric acid into a test tube and also measured its temperature and ph level. It was 22c and had a ph level of 1. Then we poured the acid into the base. The temperature of the acid + base was 26c and had a ph level of 12. I think this was chemical change because the ph level changed as well as the temperature gained a few degrees. Station 2: We placed a small piece of zinc in a test tube and then poured about 5 ml of copper sulfate to fully cover the zinc in copper sulfate. The zinc was a grey color when we original got it and the copper sulfate was blue. The zinc quickly turned a dark black color. After 15 minutes the zinc was a dark black and was disintegrating. Parts of the zinc had broken of the main piece and were at the bottom of the test tube. I think this was a chemical change because the zinc changed color and parts of it broke off. Station 3: We got another test tube filled with 5 ml’s of hydrochloric acid. The hydrochloric acid looked clear. The hydrochloric acid had a temperature of 23c. Then we added a piece of mossy zinc to the acid. 2 second after we added the mossy zinc to the hydrochloric acid bubbles started forming from the zinc. Then it started to fizz, the fizz was white. The test tube had some much white fizz in it you could not see through it anymore. At about 1 minute into the experiment the temperature started to rise. At about 4 minutes into the experiment the temperature was at 30c. The zinc at the bottom of the test tube had turned black and was still making bubbles / fizz. After about 10 minutes into the experiment the bubbles / fizz died off. This was a chemical reaction because of the white fizz. Station 4: We got a test tube and filled it with 1 inch of calcium chloride. We put a thermometer on it and it had a temperature of 22c. Then we poured 5 ml’s of water to the test tube. The temperature was at 38c after we added the water. The water had a few white particles in it, most likely from the calcium chloride. This was chemical reaction because of the temperature change. Station 5: We got a test tube and filled it with a half inch of calcium chloride and a half of inch of backing soda. Then we poured 5 ml’s of water into another test tube and took its temperature. The water had a temperature of 20c. Then we poured the water into the test tube that had the calcium chloride. The temperature rose to 24c. It then started bubbling and fizzing. The fizz was white and it came out the top of the test tube. This was a chemical reaction. Station 6: We got a test tube and filled it 10ml of 3% hydrogen peroxide. Then we added about ¼ inch manganese to the test tube. The manganese fell to the bottom and there were bubble of manganese, a top layer of manganese formed that was floating on the top of the test tube. This was a chemical reaction.