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0.4 Indigestion? which is the best commercial antacid?

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Anallysis of antacids to find out which is the best commercial antacid

Indigestion? which is the best commercial antacid?

Objectives

  • Measure the quantity of commercial antacid required to neutralize a simulated stomach acid (0.15 M hydrochloric acid) and then compare the effectiveness of several brands of antacids in neutralizing acids.
  • Learn and practice the back-titration method.

Grading

You grade will be determined according to the following:

  • Pre-lab (10%)
  • Lab Report Form (80%)
  • TA points (10%)

Introduction

The parietal cells in the stomach secrete hydrochloric acid at a quite high concentration of about 0.155 M. The flow of HCl increases when food enters the stomach. When you eat or drink too much, your digestive system may generate too much acid. You may develop a condition called "heartburn" or indigestion. Antacids are swallowed to neutralize this excess acid and "relieve" but not eliminate the condition. The reaction that takes place is an acid/base reaction. A small amount of NaOH might be as effective, although rough on the rest of the digestive system, so antacids have been formulated to reduce acidity while avoiding physiological side-effects. Many antacids use CaCO 3 size 12{ ital "CaCO" rSub { size 8{3} } } {} for this purpose.

In addition to the active ingredient (base), tablets may also contain flavors, sweeteners, binders, fillers, antifoam agents, pain relievers (aspirin), etc. In this experiment, the tablets will be analyzed only for their ability to neutralize acids. The base in antacids varies with the brand. Below is an example of active agents in several brands.

  Brand Active Agent Base
Pepto-Bismol BiO ( HOC 6 H 4 COO ) size 12{ ital "BiO" \( ital "HOC" rSub { size 8{6} } H rSub { size 8{4} } ital "COO" \) } {}
Milk of Magnesia Mg ( OH ) 2 size 12{ ital "Mg" \( ital "OH" \) rSub { size 8{2} } } {}
Rolaids NaAl ( OH ) 2 CO 3 size 12{ ital "NaAl" \( ital "OH" \) rSub { size 8{2} } ital "CO" rSub { size 8{3} } } {} (newer tablets: CaCO 3 size 12{ ital "CaCO" rSub { size 8{3} } } {} )
Tums CaCO 3 size 12{ ital "CaCO" rSub { size 8{3} } } {}
Alka-Seltzer II NaHCO 3 size 12{ ital "NaHCO" rSub { size 8{3} } } {} and KHCO 3 size 12{ ital "KHCO" rSub { size 8{3} } } {}
Maalox Mg ( OH ) 2 size 12{ ital "Mg" \( ital "OH" \) rSub { size 8{2} } } {} and Al ( OH ) 3 size 12{ ital "Al" \( ital "OH" \) rSub { size 8{3} } } {}
Gaviscon Al ( OH ) 3 size 12{ ital "Al" \( ital "OH" \) rSub { size 8{3} } } {}

 Acids are neutralized by these bases as illustrated below.

BiO ( HOC 6 H 4 COO ) + 3H + ( aq ) → Bi 3 + ( aq ) + H 2 O ( l ) + HOC 6 H 4 COOH ( s ) size 12{ ital "BiO" \( ital "HOC" rSub { size 8{6} } H rSub { size 8{4} } ital "COO" \) +3H rSup { size 8{+{}} } \( ital "aq" \) rightarrow ital "Bi" rSup { size 8{3+{}} } \( ital "aq" \) +H rSub { size 8{2} } O \( l \) + ital "HOC" rSub { size 8{6} } H rSub { size 8{4} } ital "COOH" \( s \) } {}
Mg ( OH ) 2 ( s ) + 2H + ( aq ) → Mg 2 + ( aq ) + 2H 2 O ( l ) size 12{ ital "Mg" \( ital "OH" \) rSub { size 8{2} } \( s \) +2H rSup { size 8{+{}} } \( ital "aq" \) rightarrow ital "Mg" rSup { size 8{2+{}} } \( ital "aq" \) +2H rSub { size 8{2} } O \( l \) } {}
Al ( OH ) 3 ( s ) + H + ( aq ) → Al ( OH ) 2 + ( aq ) + H 2 O ( l ) size 12{ ital "Al" \( ital "OH" \) rSub { size 8{3} } \( s \) +H rSup { size 8{+{}} } \( ital "aq" \) rightarrow ital "Al" \( ital "OH" \) rSub { size 8{2} } rSup { size 8{+{}} } \( ital "aq" \) +H rSub { size 8{2} } O \( l \) } {}
Al ( OH ) 2 + ( aq ) + H + ( aq ) → Al ( OH ) 2 + ( aq ) + H 2 O ( l ) size 12{ ital "Al" \( ital "OH" \) rSub { size 8{2} } rSup { size 8{+{}} } \( ital "aq" \) +H rSup { size 8{+{}} } \( ital "aq" \) rightarrow ital "Al" \( ital "OH" \) rSub { size 8{2} } rSup { size 8{+{}} } \( ital "aq" \) +H rSub { size 8{2} } O \( l \) } {}
CaCO 3 ( s ) + H + ( aq ) → Ca 2 + ( aq ) + HCO 3 − ( aq ) size 12{ ital "CaCO" rSub { size 8{3} } \( s \) +H rSup { size 8{+{}} } \( ital "aq" \) rightarrow ital "Ca" rSup { size 8{2+{}} } \( ital "aq" \) + ital "HCO" rSub { size 8{3} } rSup { size 8{ - {}} } \( ital "aq" \) } {}
HCO 3 − ( aq ) + H + ( aq ) → CO 2 ( g ) + H 2 O ( l ) size 12{ ital "HCO" rSub { size 8{3} } rSup { size 8{ - {}} } \( ital "aq" \) +H rSup { size 8{+{}} } \( ital "aq" \) rightarrow ital "CO" rSub { size 8{2} } \( g \) +H rSub { size 8{2} } O \( l \) } {}

In this simple experiment you will find the neutralizing capacity of various commercial antacid tablets. To test their capacity to neutralize acid, we will first dissolve an appropriate and measured amount of the sample in a simulated stomach environment. This is a solution containing a known quantity of HCl that will react with all of the antacid and still leave some extra HCl. Then we will determine how much of the original HCl remains by titrating it to neutrality with a standardized solution of NaOH. Simple subtraction will reveal how much of the acid was neutralized by the antacid tablet. This general method of analysis is called back-titration.

Note: The standardized solutions of NaOH and HCl have been prepared for you. However you need to understand how and why it is done this way. (See Supporting Information on this) Also see notes on Titration Tips.

If N A size 12{N rSub { size 8{A} } } {} is the total number of moles of HCl, and N B size 12{N rSub { size 8{B} } } {} is the number of moles of NaOH needed to back-titrate the excess HCl, then, N sample is the number of moles neutralized by the sample:

Questions & Answers

Discuss the differences between taste and flavor, including how other sensory inputs contribute to our  perception of flavor.
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While taste primarily relies on our taste buds, flavor involves a complex interplay between taste and aroma
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Not really sure
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to drain extracellular fluid all over the body.
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The lymphatic system plays several crucial roles in the human body, functioning as a key component of the immune system and contributing to the maintenance of fluid balance. Its main functions include: 1. Immune Response: The lymphatic system produces and transports lymphocytes, which are a type of
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Anatomy is the study of the structure of the body, while physiology is the study of the function of the body. Anatomy looks at the body's organs and systems, while physiology looks at how those organs and systems work together to keep the body functioning.
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Enzymes are proteins that help speed up chemical reactions in our bodies. Enzymes are essential for digestion, liver function and much more. Too much or too little of a certain enzyme can cause health problems
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Prince
how does the stomach protect itself from the damaging effects of HCl
Wulku Reply
little girl okay how does the stomach protect itself from the damaging effect of HCL
Wulku
it is because of the enzyme that the stomach produce that help the stomach from the damaging effect of HCL
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37 degrees selcius
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37°c
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37°c
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the normal temperature is 37°c or 98.6 °Fahrenheit is important for maintaining the homeostasis in the body the body regular this temperature through the process called thermoregulation which involves brain skin muscle and other organ working together to maintain stable internal temperature
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Organ Systems Of The Human Body (Continued) Organ Systems Of The Human Body (Continued)
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Source:  OpenStax, General chemistry lab spring. OpenStax CNX. Apr 03, 2009 Download for free at http://cnx.org/content/col10506/1.56
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