Chemical Reactions & Temperature Lab Investigation

Pre-Lab Information:

"In order for a chemical reaction to occur, the particles, atoms or ions, which are reactants, must physically come into contact with one another. Anything that increases the frequency of these encounters will increase the rate at which the products are formed The rate of a chemical reaction can be increased by increasing the temperature of these reactants." - Lab Paper

Lab Investigation:

This lab focused mostly on how well alka-seltzer tablets dissolve in different temperatures of water. We began with a our problem, "How does temperature affect chemical reactions." After reading our pre-lab info and considering our problem, we developed a hypothesis. Our hypothesis was, "If we do three different tests using hot, room temperature, and cold water to melt alka-seltzer, then the hot water will melt the alka-seltzer tablet the fastest. Then we started our tests. We started with the hot water test. The test began at 50˚C. The tablet was placed into the water. The tablet dissolved unevenly and surprisingly, after the tablet was introduced the water temperature rose 4.5˚C to 54.5˚C. Also, the tablet dissolved completely in 39 seconds. Next was the room temperature water. The water started out at 23.8˚C before the test. The tablet was added to the water. We noticed that the alka-seltzer dissolved more evenly in the room temperature water than in the hot water. Much like the previous test, we found a surprising discovery. Instead of the temperature increasing when the tablet was added like it had before, the water temperature actually decreased by .7˚C to 23.2˚C. The tablet took 42 seconds to fully dissolve. Lastly there was the cold water test. The test started at a chilly 2.7˚C before we added the tablet. After we added the tablet the temperature rose 1.9˚C to 4.6˚C. Unlike the other tablets, this one "danced" around the bottom while it dissolved. We also noticed that it left a layer of powder on the top. The tablet took the longest to dissolve in this test at 1 minute 55 seconds. In conclusion, I fully accepted my hypothesis.