A chemical reaction causes the chemical compositions of substances to change. Reactants are substances that enter into a reaction, and products are substances produced by the reaction. The Collision Theory Gizmo™ allows you to experiment with several factors that affect the rate at which reactants are transformed into products in a chemical reaction.
In this activity, you will simulate chemical reactions and manipulate various variables to determine the time for the reactions to fully occur.
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Go to www.explorelearning.com
 Login using the username: bannon and the password: science
 Select the “8 th Grade” tab
 Scroll down the page and find the Collision Theory gizmo and select “Launch Gizmo”
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Turn the simulation speed up to its highest setting.
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Manipulate the gizmo to achieve the following setting, determine the time for each reaction to complete.
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For each reaction use your knowledge of Reaction Rates and information from the text to explain why the rate of reaction would increase or decrease.
Standard
Reactant 1 mol/L
Catalyst 0 mol/L
Surface Area – Minimum
Temperature 100 °C
Increase Concentration
Reactant 2.0 mol/L
Catalyst 0 mol/L
Surface Area – Minimum
Temperature 100 °C
Decrease Concentration
Reactant 0.5 mol/L
Catalyst 0 mol/L
Surface Area – Minimum
Temperature 100 °C
Addition of a Catalyst
Reactant 1 mol/L
Catalyst 0.25 mol/L
Surface Area – Minimum
Temperature 100 °C
Increase in Surface Area
Reactant 1 mol/L
Catalyst 0 mol/L
Surface Area – Maximum
Temperature 100 °C
Increase in Temperature
Reactant 1 mol/L
Catalyst 0 mol/L
Surface Area – Minimum
Temperature 200 °C
Decrease in Temperature
Reactant 1 mol/L
Catalyst 0 mol/L
Surface Area – Minimum
Temperature 50 °C

1. For two molecules to react, they must collide at just the right angle and with enough energy to break the original bonds and form new ones. Based on these facts, why does the reaction tend to go more quickly at higher temperatures?
2. Why does the reaction proceed more quickly when the surface area is increased? a. What would happen if the substance was covered and the surface area was decreased? Why is this?
3. Most of the chemical reactions inside your body rely on protein catalysts called enzymes to take place.
For example, the enzyme pepsin helps to break down protein molecules in your stomach. What might happen if your stomach stopped producing pepsin?
4. Hydrochloric acid reacts with the mineral calcite to produce carbon dioxide gas, water, and calcium chloride. Based on what you have learned in the gizmo, what are three things you could do to make the reaction occur more quickly and why would they work?
Conclusion:
Write 4-5 sentences on what you learned through this activity. You must include all of the factors that affect the rate of the reaction in your response as well as content from your outline.