Introduction: Alka-seltzer contains three active ingredients, aspirin, sodium hydrogen carbonate and citric acid. It is used for headaches, migraines, and cold and flu symptoms. Alka-Seltzer is usually taken when dissolved in a glass of water. When placed in water a series of chemical reactions result into Sodium citrate and Sodium acetylsalicylate. The sodium citrate would act as the antacid for stomach pains, and the sodium acetylsalicylate would act as the pain reliever. Research Question: This investigation will determine the how the amount of water (independent variable) affects the amount the amount of time (dependent variable) it takes for the Alka-Seltzer to dissolve. Constants:
* Alka-Seltzer One tablet will be used for each trial. (note: the masses of the Alka-Seltzer might vary) * Temperature of water We will use water straight from the tap. * Substance in which the tablet is dissolved Water will be used from the tap. * Apparatus in which the tablet is contained The reaction will only occur in the same beaker. Procedure:
1. Measure 100mL in a graduated cylinder.
2. Pour the water into a 300mL beaker.
3. Drop the Alka-Seltzer in beaker with water, and start the stop watch. 4. Once the reaction finishes, and the tablet is completely dissolved, stop the time watch. 5. Record the results in a table (time)
6. Repeat steps 1-5 for the same amount of water two more times to get 3 trials for each amount of water 7. Repeat steps 1-6 the water quantities 150mL, 200mL, 250mL, and 300mL.
| Amount of Water| |
| 100 mL| 150mL| 200mL| 250mL| 300mL|
Trial 1 (s)| 56.91| 64.62| 69.69| 78.69| 74.28|
Trial 2 (s)| 63.71| 62.44| 68.64| 68.13| 78.13|
Note: All of these values were taken by a stop watch. Our reaction time was 0.22s. So all the error in the values are +/- 0.22s
Amount of Water (mL)| 100| 150| 200| 250| 300|...