North Seattle College
Chemistry 121
Lab 4: Factor Affecting Rate of Reaction
Objectives:
- To observe changes in physical and chemical properties during a variety of
chemical reactions
- To write balanced chemical equations for all reactions carried out
- To study the factor affecting the rates of reactions
Background:
A chemical reaction consists of reactants and products. The reactants are
what you start with (also called starting materials) and the products are the new
compounds that form during the reaction. Several factors affect the rate at which
reactions occur. In this lab, you will be performing six groups of reactions to
determine the effect of each of the following on the reaction rate: nature of
reactants, concentration of reactants, surface area, temperature and catalyst. The
solutions in this lab are described by their concentration in units of Molarity (M),
which is equal to number of moles of dissolved substance per liter of solution.
Pre-Lab: (To be submitted at the beginning of lab on a separate sheet of paper)
1. Write the chemical formula for each type of acid used in Part 1.
2. Which concentration of sulfuric acid do you expect to react most
vigorously with Mg in Part 3?
3. Rate is quantitative with the units of M/sec. We are not measuring
anything quantitative for this lab. How will you study the rate for this lab?
Safety Notes:
 Wear your safety goggles at all times.
 Handle all chemicals carefully (rinse them off your skin immediately).
 Take only the amount of chemicals that you need and never put unused
chemicals back into the reagent bottle.
 Discard all used or leftover chemicals in the waste containers provided
(do not pour any chemicals down the sink and do not put your rinse
water in the waste).
 Clean up any spills immediately and clean up everything when finished.
Procedures:
Carry out the following reactions. For each reaction, carefully write down
all observations. Use a clean test tube for each reaction.
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North Seattle College
Chemistry 121
Part 1. Nature of Reactants 1
1. Obtain 5 test tubes, number them, and place a 1 cm strip of Mg in each.
2. Add 1 mL of the following acids to the test tubes as described below and
note the rates:
Test tube
Observations
#1
2M sulfuric acid
#2
2M hydrochloric acid
#3
2M nitric acid
#4
2M phosphoric acid
#5
2M acetic acid
Part 2. Nature of Reactants 2
1. Obtain 3 test tubes, number them, and place 1 mL of 6.0M HCl in each.
2. Add a 1 cm polished strip of the following metals to the test tubes as
described below and note the rates:
Test tube
Observations
#1
Mg
#2
Zn
#3
Cu
Part 3. Concentration of Reactants
1. Obtain 3 test tubes, number them, and place a 1 cm strip of Mg in each.
2. Add 1 mL of the following acids to the test tubes as described below and
note the rates:
Test tube
Observations
#1
1M sulfuric acid
#2
3M sulfuric acid
#3
6M sulfuric acid
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North Seattle College
Chemistry 121
Part 4. Surface Area
1. Obtain 2 large test tubes and number them
2. Place one marble chip (CaCO3) into one test tube and about the same
amount of crushed marble chips into the other test tube.
3. Add 1 mL of 6.0M HCl into each test tube and note the rates:
Test tube
Observations
Part 5. Temperature
1. Obtain 3 test tubes and add 1 mL of 6.0M HCl to each.
2. Place one test tube in an ice bath, the second in a warm water bath, and
the third in a tap water bath.
3. Wait 5 minutes.
4. Add a piece of Zn to each test tube and note the rates:
Test tube
Observations
Part 6. Catalyst
1. Obtain 2 test tubes and add 1 mL of 3% H2O2 to each.
2. Add a few grains of MnO2 to one of the test tubes and note the rates:
Test tube
Observations
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North Seattle College
Chemistry 121
Post Lab: (what you should turn in)

Your data tables

The answers to the post-lab questions (below), written very legibly.
1. Write a balanced reaction for each of the following (including states):
Part 1. Magnesium and acetic acid
Part 2. Magnesium and hydrochloric acid
Part 3. Magnesium and sulfuric acid
Part 4. Calcium carbonate and hydrochloric acid
(Hint: there are 3 products and the gas formed here is CO2, not H2!)
Part 5. Zinc and hydrochloric acid
Part 6. decomposition of hydrogen peroxide (Hint: one product is water)
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North Seattle College
Chemistry 121
2. What would happen to the rate in part 1, if you use the same amount of
Mg but in the form of a fine powder instead of a ribbon or chunks? Why?
3. In Part 1, which reactions were the fastest? How could you tell?
4. For Parts 2-6, list the reactions in increasing rate.
For example, for part 2:
Mg + HCl < Cu + HCl < Zn + HCl
(Reaction with Mg being the slowest, reaction with Zn being the fastest)
Part 2.
_________________ < ___________________ < ___________________
Part 3.
_________________ < ___________________ < ___________________
Part 4.
_________________ < ___________________
Part 5.
_________________ < ___________________ < ___________________
Part 6.
_________________ < ___________________
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