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Alka-Seltzer Experiment

Chemistry 173 6/7 B. Alka-Seltzer Experiment. Phenomenon. Alka-Seltzer Dissolving in water Water causes the citric acid and sodium bicarbonate to react, releasing carbon dioxide which disperses the aspirin throughout the water Measured: Dissolution Time

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Alka-Seltzer Experiment

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  1. Chemistry 173 6/7 B Alka-Seltzer Experiment

  2. Phenomenon • Alka-Seltzer Dissolving in water • Water causes the citric acid and sodium bicarbonate to react, releasing carbon dioxide which disperses the aspirin throughout the water • Measured: Dissolution Time • Definition of Dissolved: The tablet is no longer visible

  3. Experiment One Manipulated Variable: Shaking or Stirring the Solution Hypothesis: If shaken/stirred, the time will decrease substantially.

  4. Data

  5. Graphical Analysis: Stirring

  6. Graphical Analysis: Shaking

  7. Discussion • The data supports the initial hypothesis overall because according to the data table the time decreases substantially compared to the initial test • Difficulties: human and physical error • For a future experiment, we would try to be more accurate as far as timing and measurement

  8. Experiment Two Manipulated Variable: Amount of Water Hypothesis: If we add water to the beaker, then the reaction time of the alka-seltzer ½ tablet and water will not change.

  9. Data

  10. Graphical Analysis

  11. Discussion • Hypothesis • Supported (for the most part) • Change in reaction time insignificant (basically +/- 1 sec. per 50 mL) • Difficulties • ½ tablet hard to get exact • Didn’t clean out beaker perfectly-not perfect tap water • Manual timing • Exact water amount • Things to change • Use full tablet to eliminate ½ tablet problems • More exact timer • More time to work on lab-more trials, cleaner beaker, better data, etc.

  12. Experiment Three Manipulated Variable:Water or Tablet first? Hypothesis: The order of operations for dissolving alka-seltzer tablets will NOT affect the time it takes to dissolve the tablet.

  13. Data

  14. Graphical Analysis

  15. Discussion • Our findings for the order or operations experiment is that it doesn't matter if you put the water or Alka-Seltzer in first. This is because the standard deviation we calculated was 2 seconds and the difference between our two means is 2 seconds. • Our initial hypothesis was that the order wouldn't make a difference in the time it takes to dissolve the tablet, and we were happy to see that this was true supported by our data. • The only difficulty we encountered when conducting our experiment was that the tablet would partially dissolve in the beaker that was supposed to be dry (for the tablet then water portion) because there was leftover water in it from using it in the other portion of our trials. • We fixed this by simply drying out the beaker with a paper towel. There are no things that we would change for a future experiment.

  16. Experiment Four Manipulated Variable: Type of Liquid Hypothesis: Because the alka-seltzer table was designed for water, it will dissolve faster in water than in any other liquid.

  17. Data

  18. Graphical Analysis

  19. Discussion • Supported hypothesis • Problems: • Inexact tablet sizes • Hard to see tablet • Hard to determine when dissolved • Next time: • Use whole tablets • Get a light to illuminate tablet • Conduct more trials

  20. Experiment Five Manipulated Variable: Temperature of the Water Hypothesis: Our hypothesis was that the water at 29.5 degrees Celsius would dissolve the Alka-Seltzer tablet faster than the water at 19.5 degrees Celsius (normal temperature of tap water), which would dissolve the tablet faster than the water at 9.5 degrees.

  21. Data

  22. Graphical Analysis

  23. Discussion • Our data does support our initial hypothesis. Just as we predicted, the tablet dissolved significantly faster with warmer water. • Some difficulties we encountered in our experiment included getting the water to exactly the right temperature, determining when the tablet was completely dissolved, and stopping the timer at the precise moment. • In future experiments, I would perhaps change the temperatures used in the experiment or the size of the Alka-Seltzer tablets (use whole tablets instead of half).

  24. Experiment Six Manipulated Variable: Size of Tablet Hypothesis:

  25. Data

  26. Graphical Analysis

  27. Discussion • Compared to a half tablet, dividing the tablet into sixths does not seem to make much of a difference. The averages are close, and the standard deviation allows for overlap. Therefore, it would not be practical for a consumer to divide the tablet into sixths. However, crushing the tablet does seem to result in a reduction in dissolving time.

  28. Overall Conclusion • What should remain the same • Pour a normal sized glass of water, then put in tablet • Water is best • Amount of water, order don’t matter • Traditional is more convenient • What could be changed • Use warm water • Should stir water • Consumer could crush tablet first

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