MINILAB 14.2 Antacids

Many people experience a burning sensation known as heartburn after eating certain foods. Heartburn is caused by excess acid in the stomach and esophagus. Use your knowledge of acid chemistry to evaluate the effects of antacids that are commonly used to treat heartburn.

OBJECTIVE TO TEST AND EVALUATE THE EFFECTS OF SOME ANTACIDS.

HYPOTHESIS

MATERIALS four snack-size zipper-closure bags, marker, antacids, white vinegar, water, universal indicator, pH color chart

PROCEDURE

1. Obtain four snack-size zipper-closure bags, and mark each with the name of an antacid to be tested.

2. Label one beaker H₂O and fill with distilled water to about 45 mL.

Label the second beaker HC2H3O2 and fill with 25 mL of vinegar.

3. To each of the four bags, add 5 mL of white vinegar, 10 mL of water, and enough universal indicator (probably 10 to 15 drops) to impart a distinct color.

4. Break the antacid tablets into small pieces. Add the appropriate antacid tablet to each bag, squeeze out the excess air, and zip the bag closed. Be sure that the antacid tablet is immersed in the vinegar solution.

5. Record your observations. When the reactions have ceased or slowed markedly, note and record the colors and approximate pH values of the solutions. Consult the pH color chart on page 504 of your textbook.

OBSERVATIONS

BRAND OF ANTACID

INITIAL COLOR (STEP 2)

FINAL COLOR (STEP 4)

pH PAGE 504

NEUTRAL FINAL PRODUCT?

ANALYSIS

1. Describe the different ways in which the antacids reacted with the vinegar. Infer which of the antacids contain carbonates. Explain your answer.

2. Which of the antacids created the most basic final solution? Explain this answer in terms of how well the antacid works.

3. Why break up the tablets?

4. What antacid do you think would work the best? Support your answer.