Antacid Laboratory Investigation
Purpose: In this lab, you will select two antacid tablets to compare to one
another.
Antacids work by absorbing the excess acid in your stomach to relieve
heartburn. Some products work better than others. The ones that raise the
pH fastest provide the most immediate relief. Others may take a longer time
to take effect, but may raise the pH to a higher level in the end.
Students will compare the pH of three solutions BEFORE adding an
antacid, then measure the pH every minute for 15 minutes after the antacid is
added. They will then determine which one worked fastest, and well as which
one raised the pH to the highest level.
Materials: HCl or orange juice (depending on availability), glassware, pH
paper, timer, spoons, mortar and pestle, and the two products tested:
______________________________ and _______________________________
Hypothesis: Which product do you think will work better, and why do you
think so? (For the why, is it based on past experience in using the product, or
something on the label that makes it seem like it should work better?)
Procedure:
1. Obtain 3 beakers. To each, add 25 mL of HCl (or if using orange juice,
add 50 mL).
2. Label each of the beakers – control, and the names of each of the two
antacids you are testing.
3. Tear off three strips of pH paper and test the pH of each of the three
beakers. Record your results in the data table.
4. With a mortar and pestle, crush the recommended dosage of each
antacid product you have chosen to test. Put the crushed contents in a
cup beside the appropriate beaker. DO NOT ADD THEM INTO THE
BEAKER YET.
5. Once both sets of tablets have been crushed, set your timer to zero.
6. At the same time, add both sets of tablets to the appropriate beaker, and
start your timer.
7. Using a spoon, mix the powder continuously until dissolved.
8. At each minute, take the pH of each beaker, and record the results in
your data table.
9. At the end of 15 minutes, throw out the spoon and pH paper strips.
10.
Rinse the mortar and pestle in the sink, and rinse all solutions
down the sink with lots of water.
11.
Glassware and mortar and pestle should be placed by the drying
rack.
Data table: on the back
Analysis:
1. Which one raised the pH the fastest? How fast did it change?
2. Which on raised the pH the highest? How long before it reached this pH
level?
3. Look at the labels for the antacids. Why did one of them work faster
and/or raise the pH to a higher level? (Consider the ingredients in
answering this question.)
4. What was the purpose of the control?
5. How could human error have resulted in incorrect data? What could be
done to correct this?
Data table:
Time
(minutes)
pH
Control
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15