Student
EXPERIMENT SIX - ANALYSIS OF STOMACH ANTACID TABLETS
Purpose
In this experiment you will measure the amount of stomach acid consumed (or neutralized) by various antacid tablets (Maalox, Tums, Rolaids: no Pepcid or Tagamet!). If you have a favorite one, bring a package to the lab (one color only).
Inside your stomach, excess hydrochloric acid is neutralized by the antacid. Different antacids use different metal hydroxides, such as Al(OH)3 or Mg(OH)2. The general formula for this reaction is:
M(OH)y + Y HCl [pic] Y H2O + M+y + Y Cl-
Additionally, some brands of antacids use calcium carbonate as a neutralizing reagent.
CaCO3 + 2 HCl (aq) [pic] H2CO3 (aq) + Ca2+ (aq) + 2 Cl-(aq)
The carbonic acid formed in this reaction may undergo further reaction:
H2CO3 (aq) [pic] H2O (l) + CO2 (g)
Procedure Outline
This experiment will involve several steps. The first step will involve a simple reaction to determine the concentration of the NaOH that will be used in this experiment using a solid acid standard. Using the standardized NaOH, the next step of the lab will involve determining the concentration of the HCl. Once we have the concentration of the standardized HCl, we will conclude the lab by determining the amount of acid that is consumed when you use an antacid tablet. First the tablet is dissolved and an excess of acid of known concentration is added to the tablet. The solution is then briefly heated to insure that all of the antacid reacts. Finally, the remaining unreacted acid is titrated with base (NaOH) to determine the amount left over and hence, the amount that reacted with the tablet. The chemical reaction which occurs is:
NaOH(aq) + HCl(aq) [pic] NaCl(aq) + H2O(l)
A detailed description of the individual steps in the analysis follows. Before we get started, there are a few points on using a buret that need to be covered. Adding a solution from a buret can be a little tedious, but the errors that are technique dependant will cause errors
Purpose
In this experiment you will measure the amount of stomach acid consumed (or neutralized) by various antacid tablets (Maalox, Tums, Rolaids: no Pepcid or Tagamet!). If you have a favorite one, bring a package to the lab (one color only).
Inside your stomach, excess hydrochloric acid is neutralized by the antacid. Different antacids use different metal hydroxides, such as Al(OH)3 or Mg(OH)2. The general formula for this reaction is:
M(OH)y + Y HCl [pic] Y H2O + M+y + Y Cl-
Additionally, some brands of antacids use calcium carbonate as a neutralizing reagent.
CaCO3 + 2 HCl (aq) [pic] H2CO3 (aq) + Ca2+ (aq) + 2 Cl-(aq)
The carbonic acid formed in this reaction may undergo further reaction:
H2CO3 (aq) [pic] H2O (l) + CO2 (g)
Procedure Outline
This experiment will involve several steps. The first step will involve a simple reaction to determine the concentration of the NaOH that will be used in this experiment using a solid acid standard. Using the standardized NaOH, the next step of the lab will involve determining the concentration of the HCl. Once we have the concentration of the standardized HCl, we will conclude the lab by determining the amount of acid that is consumed when you use an antacid tablet. First the tablet is dissolved and an excess of acid of known concentration is added to the tablet. The solution is then briefly heated to insure that all of the antacid reacts. Finally, the remaining unreacted acid is titrated with base (NaOH) to determine the amount left over and hence, the amount that reacted with the tablet. The chemical reaction which occurs is:
NaOH(aq) + HCl(aq) [pic] NaCl(aq) + H2O(l)
A detailed description of the individual steps in the analysis follows. Before we get started, there are a few points on using a buret that need to be covered. Adding a solution from a buret can be a little tedious, but the errors that are technique dependant will cause errors