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Open- Inquiry Investigation: Antacid Effectiveness

How does the effectiveness of an antacid differ when the expiration dates differ?

Janelle You

on 23 May 2011

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Transcript of Open- Inquiry Investigation: Antacid Effectiveness

Inquiry Lab Antacid Effectiveness By Janelle You, Joey Ooka, & Scott Fukuoka Problem How does the expiration date of an antacid affect its effectivness? Hypothesis If the antacid expires then it will not be effective because the reactants will not be as reactive anymore. Independent variable Controls The controls of the experiment are the type
of antacid, mass of antacid used, & amount
of hydrochloric acid used. Procedure Mix 10 mL of hydrochloric acid and 10 mL of water together in a beaker. Make six beakers filled with this mixture.
Choose one flavor of the antacid for both the expired and unexpired antacids.
Crush 3 tablets of regular strength expired antacid.
Crush 3 tablets of regular strength unexpired antacid.
Zero a piece of paper and then add the expired antacid until there is 1 gram.
Do this until there are three samples of 1.00 gram of the expired antacid tablets.
Repeat the same process for the unexpired antacid tablets.
Place one of the measured 1.00 gram antacid tablets into a beaker with hydrochloric acid and water.
Let the solution react for 2 minutes.
Place a litmus paper into the solution.
Record the pH of the solution.
Repeat the same process for the rest of the expired samples and also all of the unexpired samples. 2HCl + CaCo3 -> H20 + CO2 + CaCl2 Balanced Equation Trials

Trial 1
Trial 2
Trial 3 Expired

No Unexpired

Yes Reaction of Expired or Unexpired Antacids Data Analysis One source of error is that we do not know how the antacids were treated before the eperiment. Because the expired antacid was from the year 2004 and the other was from 2011, the expired antacid could have gone through different treatment than the antacid that was recently bought. Another source of error would be that some of the crushed antacid remained on the paper. If some antacid remained on the paper then the amount of antacid that was put into the solutions could have differed from one another. A third source of error may be that the beakers with the unexpired antacids were shaken to hasten the reaction when that was not done for the expired antacid. This could be the difference. Perhaps the expired antacid needed to be shaken in order to get the reaction started. Although unlikely, it is possible. Conclusion In conclusion our hypothesis was proved correct. When the antacid was expired, the solution remained as an acid and did not react. The newer antacids reacted instantly and changed the solution from an acidic solution to a neutral solution. When the antacid expires, its effectiveness wears off over time. 1.









12. Results 2HCl + CaCO3 = H20 + CO2 + CaCl2
Hydrochloric Acid + Calcium carbonate = Water + Carbon Dioxide + Calcium Chloride

When adding 10.0mL of HCl (1M) and 1.00g of Calcium Carbonate (from the generic Antacid), what is your limiting factor? Your excess factor? How much of the excess is left over?

Limiting: 10.0mL of HCl
Excess: 1.00g of Calcium Carbonate

(10.0mL HCl) x (1L) x (1mole HCl) x (1mole CaCO3) x (100.09g) = 0.500g of CaCO3 used
(1) (1000mL) (1L) (2 moles HCl) (1 mole CaCO3)

1.00g 0.500g = 0.500g of CaCO3 remaining The expiration date of the antacid
is the independent variable of the
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