# Alka Seltzer Experiment

1. Jun 15, 2007

### Juicyfruit11

Part I: Temperature and Reaction Rates

Materials

*

Three Alka-Seltzer tablets
*

Water
*

Three coffee cups
*

Ice
*

Thermometer
*

Watch with seconds

Procedure:

1.

Chill some water with the ice.
2.

Pour just the water into one coffee cup.
3.

Heat some water and place it in a second coffee cup.
4.

Put room temperature water into the third cup.
Use the thermometer to record, in a data table, the temperature of the water in each cup.
5.

Simultaneously (get help from another person), add one full Alka-Seltzer tablet to each cup and begin timing with your watch.
6.

Record the amount of time needed for each reaction to reach conclusion (stops fizzing).
7.

*

Part II: Particle Size and Reaction Rates

Using mathematics, it is possible to compare the surface area of an object to its volume and get a ratio. Interestingly, if you crush a tablet, the ratio of surface area to volume will be higher in the smaller particles than with the whole tablet.

Materials

*

Three Alka-Seltzer tablets
*

Water
*

Spoon
*

Three coffee cups
*

Watch with seconds

Procedure

1. On a piece of paper, grind up one tablet with the back of the spoon until it is a fine powder.

2. On a second piece of paper, chop one tablet into several small pieces but do not grind it.

3. Fill the three cups with the same amount of water
Note: the water should be approximately the same temperature at the start.

4. Simultaneously (again, get help), add the ground tablet to one cup, the chopped tablet to a second cup, and the whole tablet to the third cup. Begin timing with your watch.

5. Record the amount of time needed for each reaction to reach conclusion (to stop fizzing).

Note: On the Y axis = time of reaction; on X axis where you are putting "surface area exposed" use 1 = for whole tablets; 5 for small pieces; 10 for crushed.

Analysis

You will submit these analysis questions and your two graphs! Make sure you include your data and two graphs.

1. What differences did you observe in the reactions in the three cups in Part I?

2. Look at your graph of temperature vs. reaction time. Describe this graph in mathematical terms—e.g., linear, parabolic (curved up).

3. As temperature increases, what happens to reaction time?

4. What differences did you observe in the reactions in the three cups in Part II?

5. Look at your graph of surface area vs. reaction time. Describe this graph in mathematical terms.

6. As surface area increases (smaller particles), what happens to reaction time?

7. Based on your data, under what conditions would you expect the reaction between baking soda and vinegar to occur most quickly?

Alright, I don't have any way to get Alka Seltzer in the next couple of days, so I wouldn't be able to do this experiment. Any ideas on what will happen in each experiment?

2. Jun 15, 2007

### lalbatros

you can try with any other kind of effervescent tablets