Name: ___________________
Reaction Rate Readiness PreLab
Act ______
Hydrogen peroxide, H202, is usually purchased in bottles that contain a solution that is
97 percent water and 3 percent hydrogen peroxide by mass. Hydrogen peroxide is
not a very stable compound. When it breaks apart it produces Oxygen gas ( O 2 ) and
water (H2O). This usually happens slowly. After a few years a bottle of hydrogen
peroxide will have very little hydrogen peroxide left.
Prelab Questions
1: When hydrogen peroxide breaks apart to form oxygen gas and water, it is the only
reactant in the reaction. What might cause its molecules to break apart without any
other reactant?
2. Write the chemical equation for H2O2(l) breaking apart into O2(g) and H2O(l).
3: If I want 2 moles of hydrogen peroxide (H2O2), then how many grams hydrogen
peroxide should I measure out?
Extended: Normal bottles of 3 percent hydrogen peroxide contain 3 grams of H2O2
per 100 mL. How many moles of hydrogen peroxide are in every milliliter taken from a
bottle of hydrogen peroxide solution.
4. Think about what you just read about the reactant hydrogen peroxide (H2O2) and
what you already know about its products, oxygen gas (O2) and water (H2O). Do you
think this will be an exothermic or endothermic reaction? Explain your thinking.
5. Imagine we try to speed up this reaction. What could we do to try and speed this
reaction up?
6.How could we measure how fast the
reaction produced oxygen gas? Look at the
picture for ideas.
What would our units be if we used a
graduated cylinder and a timer?
Topic:
What I know about this topic:
Manipulated Variable Brainstorm
Things I could change:
Responding Variable Brainstorm
How I could measure the affect of the changes I make (what tools will I need? What
kind of measurements will I record):
Choosing my variables
I will change (manipulated)
I will measure (responding)
I will keep the same every time (controlled variables):
Name: ___________________ Pre-planning: Designing an Investigation
Act ______
Testable Question
How will playing loud music to hydrogen peroxide and a catalyst
(describe how you will change your manipulated variable)
affect the rate the reaction produces oxygen gas?
(your responding variable- what you are going to measure)
Prediction : I think oxygen gas will be made at a higher rate when loud music is
played than when the reaction happens in a quiet place.
(what you think will happen to the responding variable when you change the manipulated variable)
Procedure
Others should be able to follow your procedure and get similar results
Materials I will need:
ipod and speaker, Graduated cylinder, stand, clamp, tub, water, 3% hydrogen
peroxide, flask, stopper with tube, potassium iodide (KI), small plastic vial for the
catalyst (KI) pipettes and a timer
Set up - How I will set up the experiment:
1. Fill a tub with water
2. Fill a graduated cylinder with water and then turn it upside down while in the
water, without letting the water fall out.
3. Use the clamp to hold the cylinder full of water upside down when the opening
under water. Make sure the numbers can still be read.
4. Measure 4 ml of hydrogen peroxide with a pipette (see the 1 ml mark on the
pipette) and place in the flask
5. Place the opening of the rubber tub under water and inside the graduated
cylinder full of water
6. Measure 2 ml of KI with a different pipette and place it in the small plastic vial.
Basic Experiment. Steps to do the experiment and measure the responding variable
the first time. Note: Include the step: Record __________________ (whatever you are
recording)
Do steps 7 - 11 in a quiet place.
7. Very carefully place the vial with 2 mL of KI in the flask with 4 mL H2O2 so that
the two liquids don’t mix.
8. Seal the flask with the stopper that is connect to the rubber tub going into the
graduated cylinder
9. One person tilt the flask so that the KI mixes completely with the H2O2 while
another person starts the timer
10. Stop the timer when oxygen gas has pushed the water level in the graduated
cylinder down to the 10 mL mark.
11. Record the time.
12. Dump waste into waste container, rinse the flask out and reset the experiment
following steps 1 – 6.
Measuring affect of changes. Steps to do the experiment again with your changes
(manipulated variable)
13. Place the speakers 2 inches from the flask of hydrogen peroxide and turn on
the music to the song Thrift Shop.
14. Repeat steps 1-12 with music on at a volume level of 5.
15. Repeat steps 1 – 13 with the music turned up to level 10.
Trials - directions on how many trials (exact repeats of the experiment so far)
16. Repeat steps 1 – 15 at least 2 more times.
Calculations – describe any calculation that should be performed
17. Divide the volume of gas (10 mL) by the time recorded to get the results in
mL/second
Data Table Title: How loud music affects the rate of a reaction
Manipulated Variable (units):
Music Volume
Time to produce 10 mL of gas (seconds)
Trial 2
Trial 3
Average
Responding Variable (units):
Trial 1
0
5
10
Calculations will be written below the results
Calculations: 10 ml ÷ time (sec) = the rate of the gas was produced (ml/sec)