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Challenge #2: Lab Worksheet #1

Station One: Let’s Concentrate At This Station!

Date of Investigation:

Name of Scientist:

Name of Recorder:

Purpose: The purpose of this lab investigation is to observe how the change in concentration of hydrochloric acid changes the rate at which chalk reacts.
Hypothesis: If the concentration of hydrochloric acid increases then the rate at which chalk reacts will (increase or decrease).

Materials:

• Safety glasses, aprons and rubber gloves
• MSDS on hydrochloric acid
• Three 100 mL beakers labeled with various concentrations of diluted hydrochloric acid
  • Beaker A = 1.0 M HCl(aq) (approximately 3.0% HCl(aq))
  • Beaker B = 0.1 M HCl(aq) (approximately 0.3% HCl(aq))
  • Beaker C = 0.01 M HCl(aq) (approximately 0.03% HCl(aq))
• Three small 50 mL beakers
• Equal pieces of chalk (approx. 2 cm)
• One bottle of distilled water
• One Stop Watch
• Disposal container

Procedure:

1. First read ALL of the procedures before you begin.
2. Place a 2 cm piece of chalk into a small beaker.
3. Add Acid A carefully to the 10 mL line to the beaker labeled A.
4. Start the stopwatch.
5. Stop the stopwatch when no more bubbles are produced.
6. Record the time of the reaction (in seconds) in the Observation Chart on the following page.
7. Pour the contents of this beaker into the waste container.
8. Repeat Steps 2 to 7 with Acid B in the next beaker labeled B.
9. Repeat Steps 2 to 7 with Acid C in the next beaker labeled C.
10. Clean up your station. Complete the checklist below before proceeding to the next station.
    • Rinse all beakers with a little distilled water.
    • Wash the counter space.
    • Wash your hands.