Reaction+Rates

Reaction Rates and Catalysts

Note: For netlogo materials to supplement this lesson, please go here and here.

Author: Daniel Sinkovitz, 2011


 * Open Simulation**

> or use this URL: []
 * 1) Google: **concord molo catalyst** and click the first link


 * 1) Click “Go To Activity”


 * Important Instructions**


 * You will do the steps in a different order. First do steps 1, 2, and 3.
 * Then skip to step 6. If you have time, go back and do steps 4, 5, 7, and 8.


 * You will not write your answers on the computer. Instead, write them on this worksheet.


 * Step 1: Introduction**

When does a chemical reaction occur? (See computer. Write your choice and explain.)

What type of reaction is shown in the simulation?

Is the reaction shown exothermic or endothermic? How do you know?


 * Step 2: Interpreting Chemical Notation**

Describe what happens in the following reaction: A + B2 --> AB + B

What type of reaction is this?


 * Step 3: Factors Affecting Reaction Rates**

Write down data from the experiments you do. For temperature, record how far up the slider (10%, 50%, 100%) you set it. For concentration, write how many atoms you started with in the box. **//Use this data as evidence to justify your anwers.//**


 * ** Trial **

|| ** Temperature ** ** (% up the scale) ** ||  ** Concentration ** ** (# of atoms) ** ||  ** Time to reach 80% reacted (fs) **  || How does reactant concentration affect the rate of a chemical reaction? (**//use data as evidence!//**)
 * ** 1 ** ||   ||   ||   ||
 * ** 2 ** ||   ||   ||   ||
 * ** 3 ** ||   ||   ||   ||
 * ** 4 ** ||   ||   ||   ||
 * ** 5 ** ||   ||   ||   ||
 * ** 6 ** ||   ||   ||   ||
 * ** 7 ** ||   ||   ||   ||
 * ** 8 ** ||   ||   ||   ||
 * ** 9 ** ||   ||   ||   ||

Explain why concentration has this effect (or no effect) on the rate of a chemical reaction.

How does temperature affect the rate of a chemical reaction? (**//use data as evidence!//**)

Explain why temperature has this effect (or no effect) on the rate of a chemical reaction.

(Next page): Explain how you solved the challenge and why your strategy worked.


 * Step 6: Catalysis**

Describe your observations of how a catalyst participates in the reaction.

Why does the formation of A-B only happen when the catalyst is added?

If you could adjust the bond strengths of A-A, or B-B, how would you change them to speed up the reaction?

It is often said that catalysts work by lowering the activation energy (energy needed to get a reaction started). What do you see that seems to support that idea?


 * Challenge:** Go on to steps 4, 5, 7, and 8 if you have time.

Write your answers on a separate sheet of paper.