Turns, Rolaids or Maalox.... Fighting the Stomach Acid Blues
Americans spend thousands of dollars yearly to neutralize excess stomach acid... and
fight acid indigestion. The ads claim these tablets "soak up excess stomach acid' in a
matter of minutes, and that each is the "BEST". NOW is our chance to rate the claims by
experimentation, and learn about pH and acids and bases at the same time.
 Fill out your ExD before beginning & get a stamp before beginning the lab.
 Attach it to your lab write-up.... yes, its required!
 SET UP YOUR DATA TABLE NOW - you'll collect both team and class data and
use it for statistical analysis.
Materials:
3 - 400 ml beakers
Universal Indicator
distilled water
3 Stirring rods
Mortar & pestle
Balance
1.0 M HC1
Univ. Ind. color chart
Methods:
1. Fill each beaker with 150 ml distilled water.
2. Add 5 drops of 1.0 M HC1 (hydrochloric acid) to each beaker.
3. Add 10 drops of Universal Indicator to each beaker.
4. Record the pH of each beaker's solution by the color of the Universal Indicator (see color charts)
5. Weigh and record the MASS in grams of each of the 3 tablets.
6. Grind Turns tablet using the mortar & pestle and add it to one of the beakers. Clean the mortar
& pestle and grind the next tablet, etc.
7. Stir the tablet with the stirring rod until it dissolves. (5-8 minutes)
8. Record the pH of the resulting solution by the color of the Universal
9. Indicator solution.
10. Make observations during the experiment and write them down. These are qualitative
observations - which dissolves fastest, etc.
11. Do the calculations and record your team data. Add it to class data on board. Round to the
nearest 0.1.
Results:
SAMPLE DATA
Color solution before
adding tablet
Maalox
Tums
Rolaids
Do not write
On
This Page!
SAMPLE DATA
TABLE ONLY
pH before adding tablet
Mass tablet in grams
Color after dissolved & pH
Leslie Hays, Helix Charter HS
Results & Calculations (continued):
1. Calculate the pH differences for each tablet using the pH as measured by the Universal
Indicator. (Beginning pH - Final pH)
2. Calculate the pH unit change per gram of tablet - A pH/gram - then rank in order the relative
ability to neutralize the acid in the beaker, using #1 for the best neutralizer, #3 for the worst.
SHOW YOUR WORK - NEATLY (Example: pH change of 25, tablet mass of 5 grams = 25 pH/5g = 5 pH
change per gram. The biggest pH change per gram would be the BEST acid reducer!)
3. Graph your results using the CLASS DATA. Y axis = A pH/gram; X axis = bars of each tablet
type. Don't forget the title, and a brief conclusion statement explaining the graph.
4. Make a Box & Whiskers of the 3 tablets compared to one another. (See example on board.)
5. Do a cost analysis of the price of each antacid per gram, or per tablet. [Get the cost information
from your teacher.] Include this data in your analysis.
Analysis:
Write several paragraphs and discuss the results of this lab. Relate your specific results back to your
hypothesis.
 Did you support your hypothesis or revise it?
 What sources of error may have existed that affected your data collection?
 How do antacids work?
 What would you now advise friends or family about use of these tablets?
Universal Indicator Color Chart
You and your partner must agree on the color of the solution, then select the best pH match
below.
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Leslie Hays, Helix Charter HS
Red =
Orange =
Yellow =
Green =
Blue green =
Blue =
Dark blue =
Violet =
pH 4.0
pH 5.5
pH 6.5
pH 7.0
pH 8.0
pH 8.5
pH 9.0
pH 10.0