Chemical Reactions and Heat Lab

Today we tested 2 reactants (water and alka-seltzer tablets), and put them together to form a product. We learned about the chemical reaction that occurred when you put one of the tablets into water. The catalyst we used to change the rate of the reaction was the temperature of the water.

My hypothesis was that if you increase the temperature, the reaction will occur faster. In other words, if the temperature of the water is at a hot temperature, then the alka-seltzer tablet will dissolve more quickly in the water then when the water is at a colder temperature. For this experiment we used a beaker to hold the water, a temperature probe to measure the temperature of the water, Logger Pro software to record the data, a hotplate to heat the water, and some ice to cool the water. We did a series of 3 tests. These were the results:

For the first test, we heated the water to about 50 degrees Celsius and then we dropped the alka-seltzer tablet into the water. here is a diagram depicting this test:

We then measured the amount of time it took the alka-seltzer tablet to completely dissolve. Here is a graph showing the temperature of the water over time:

My group, (Kira Jake and I), found that it took around 10 seconds for the tablet to completely dissolve in the water. Here's is a video  of the tablet dissolving in the hot water.

For the 2nd test we used the same process but instead of having the temperature of the water be hot, it was room temperature (about 23 degrees Celsius).
Here is a diagram of the 2nd test:

Here is a graph that shows the temperature of the room-temperature water over time:

The time it took for the alka-seltzer tablet to dissolve in the room-temperature water was significantly higher than the time it took for the alka-selstzer tablet to dissolve in hot water. It took around 29 seconds.
Here is a video of the alka-seltzer tablet dissolving in the room-temperature water:

The 3rd and final test had the temperature of the water around 1.7 degrees Celsius, the lowest temperature for all 3 tests. Again, we followed the same procedure, and measured the time it took for the tablet to dissolve in the water. Here is a diagram of the 3rd test:

Here is a graph showing the temperature of the ice-water over time:

I found that the time it took for the alka-seltzer tablet to completely dissolve in the ice cold water was about 153 seconds. This was the longest amount of time for all 3 tests.

Here is a table showing the temperature and reaction time for all 3 tests:

And here is a graph showing the relationship between temperature and time of the tests:

My hypothesis was supported because the hotter the temperature, the faster the reaction rate. Test 1 was the had fastest reaction rate, and it was the hottest test. The 2nd test had a middle temperature, and had a rate that was in between tests 1 and 3. The 3rd test had the lowest temperature, and the slowest reaction rate.

If I could do anything differently, I would probably just be less coatis and save time. I read the directions first, which helped, but I felt that my group moved slower than we should have.