Factors Affecting Rate of Reactions
Objective: Study the factors affecting the rates of reactions.
Pre-Lab Questions: Answers submitted at the beginning of lab.
1. List some factors that affect the rate of reactions.
2. Rate is quantitative with unit of M/sec. We are not measuring anything
quantitative for this lab. How would you study the rate for this lab?
Part 1: Nature of reactants 1
Procedure:
1. Obtain 5 test tubes and number them #1 to #5.
2. Place ~5 Mg turning pieces in each test tube.
3. Add 1mL of 2M sulfuric acid to test tube #1, 1mL of 2M hydrochloric acid to #2,
1mL of 2M nitric acid to #3, 1mL of 2M phosphoric acid to #4, 1mL of 2M acetic
acid to #5.
4. Note the rates.
5. Write a balanced equation between Mg and acetic acid, including states.
Part 2: Nature of reactants 2
1.
2.
3.
4.
5.
Obtain 3 test tubes and number them #1 to #3.
Place 1mL of 6M hydrochloric acid in each test tube.
Add ~5 pieces of Mg turnings to test tube #1, Zn to #2, and Cu to #3.
Note the rates.
Write a balanced equation between HCl and Mg. Make sure to include states.
Part 3: Concentration of reactants
1. Obtain 3 test tubes and number them #1 to #3.
2. Place ~5 Mg turning pieces in each test tube.
3. Add 1mL of 1M sulfuric acid to #1, 1mL of 3M sulfuric acid to #2, and 1mL of
6M sulfuric acid to #3.
4. Note the rates.
5. Write a balanced equation between Mg and sulfuric acid, including states.
Part 4: Surface area
1. Obtain 2 large test tubes. Place one CaCO3 (marble) chip into one test tube and
about same amount of crushed CaCO3 into the other test tube.
2. Add 1mL of 6.0M hydrochloric acid to each test tube.
3. Note the rates.
4. Write a balanced equation between CaCO3 and hydrochloric acid, including
states.
Edited by Kristine Schroeder 7/12/2016
1
Part 5: Temperature
1. Obtain 3 test tubes and add 1mL of 6.0M hydrochloric acid to all three.
2. Place one test tube in an ice bath, the second in a warm water bath, and the third
in a tap water. Wait 5 minutes.
3. To each test tube, add a piece of Zn.
4. Note the rates.
5. Write a balanced equation between Zn and hydrochloric acid, including states.
Part 6: Catalyst
1. Obtain 2 test tubes and add 1mL of 3% H2O2 to both.
2. Add few grains of MnO2 to one of the test tubes.
3. Note the rates.
4. Write a balanced equation for decomposition of H2O2 including states.
Post-Lab Questions:
1. How did you note the rate for each part? i.e. Color changing to red? Test tube
getting hot?
2. What would happen to the rate in Part 1, if you use cubic chunks of Mg instead
of Mg turnings of same amount? Why?
Summary:
For each part, list the reactions in increasing rate.
For example:
In Part 2, Mg + HCl < Cu + HCl < Zn + HCl (Zn being the fastest reaction)
Note: “Mg < Cu < Zn” is not complete!
Edited by Kristine Schroeder 7/12/2016
2