Student+Assignment

Problem Statement
How does temperature affect the rate of dissolution?

How does surface area affect the rate of dissolution?

Lab Experiment - In Class
Split up into 8 groups of 3 and go to assigned workbench.

** Part 1- Temperature **
> Station 1: ~5 degrees Celsius > Station 2: ~15 degrees Celsius > Station 4: ~25 degrees Celsius > Station 5: ~50 degrees Celsius and 90 degrees Celsius
 * 1) Add 250mL of water to the 500mL beaker
 * 2) Adjust water temperature according to your station (add ice to make it colder, put on hotplate to make it warmer)
 * 1) Record the actual temperature of the water before you add the alka-seltzer tab. Leave the thermometer in for about a minute before you read the temperature.
 * 2) Have someone ready with the stop watch in their hand
 * 3) Add the alka-seltzer tab to the water and start the timer as soon as it enters the water
 * 4) Stop the timer once the entire tablet has dissolved
 * 5) Record your time on the board
 * 6) Copy down all results in your table

** Part 2 - Surface Area **

 * 1) Add 250mL of water to the 500mL beaker
 * 2) Have someone ready with the stop watch in their hand
 * 3) Add the alka-seltzer tab provided to you to the water and start the timer as soon as it enters the water
 * 4) Stop the timer once the entire tablet has dissolved
 * 5) Record your time on the board
 * 6) Copy down all results in your table

a) For temperature data:
- First column should be temperature (oC) - Second column should be time (seconds) b) For surface area data: - First column should be surface area (full, broken, crushed, grinded)  - Second column should be time (seconds)  2. Make a scatter plot for your temperature data and surface area data  3. Add a line of best fit to your graphs and write the equation.

** Questions **

 * 1) What trend did you see for your temperature versus time graph?
 * 2) Describe this trend using the particle theory.
 * 3) What trend did you see for your surface area versus time graph?
 * 4) Describe this trend using the particle theory.
 * 5) How fast do you think it would take for an alka-seltzer tab to dissolve if the temperature were 150 o C?

Conclusion
Restate the hypothesis using conclusions from the lab support whether the hypothesis was true or not. Give possible sources of error. In details describe what was learned from the experiment.