Unit 11 Review Created by Mrs. Martin

1. List the 6 factors that affect the rate of a reaction.

1. Answer 1. Nature of reactants 2. Concentration 3. Surface area 4. Temperature 5. Pressure (gases) 6. Catalysts

2. Answer Label the pieces of the graph.

2. Answer A = reactants B = activated complex (transition state) C = products D = Activation energy (E a )

3. List the 3 points to the Collision theory. If you can list it all in 1 statement – even better.

3. Answer Particles must collide with sufficient energy and in the proper orientation for a chemical reaction to occur.

4. Does this diagram show an endothermic or exothermic reaction?

4. Answer This is an exothermic reaction. The reactants are at a higher energy level than the products. With an endothermic reaction, the products would be at a higher energy level than the reactants.

5. Draw this diagram. Draw what the reaction line would look like if a catalyst was used.

5. Answer The dotted line shows the reaction with a catalyst because it is showing 1. An alternative pathway for the reaction to happen 2. A lower activation energy needed with alternative pathway

6. The aqueous solution reaction I am doing is happening too fast. Explain what I could do to the temperature to slow the reaction down and how the change in temp would cause the slow down.

6. Answer If you lower the temperature of the solution, the reaction will slow down. This is because as the molecules slow down, they don’t collide as often. Also the energy of those collisions will be less which also slows down the reaction.

7. 2A + 3B  C + 4D At s the [B] is 0.100M. At s, the [B] is M. Determine the rate of the reaction for B.

7. Answer

8. 2A + 3B  C + 4D Using the data from #7. What is the rate of the reaction for D at the same time?

8. Answer

9. True or false The rate of a reaction is constant over the length of the data collection. Correct any false statements to make them true

9. Answer False - Over time a reaction becomes slower because there are less reactants available to make product. Also there are product molecules in the way of the collisions needed by the reactants to create the products.

10. Explain how concentration of reactants can affect the rate of the reaction.

10. Answer If you increase the [reactants], there are more molecules present for collisions, so the rate of the reaction increases. If you decrease the [reactants], there are less molecules present for collisions, so the rate of the reaction decreases.

11. True or false When the reaction vessel’s volume is increased, the rate of the reaction also increases. Correct any false statements to make them true

11. Answer False - When the reaction vessel’s volume is increased, the rate of the reaction also decreases because there is more space for the molecules to be in, which means less collisions.

12. Explain how using LARGER pieces of CaCO 3 during our rates lab would have affected the rate of the reaction.

12. Answer Using larger pieces of CaCO 3 during our rates lab would have caused the reaction to happen slower because the big pieces have a small over all surface area. With a small surface area, there are less chances of collisions which reduces the rate of the reaction. Large surface areas will give faster reaction rates

13. Explain which reaction will happen faster.

13. Answer Reaction B will happen faster because it has a lower activation energy (size of the hill).

14. When AB 3 and BC collide in the orientation shown, explain if the reaction will occur. Make a drawing correction if needed.

14. Answer The reaction won’t happen because the C and the A are coming in contact, but in the products, A and C are not bonded together. For the right orientation, The B of the BC molecule must come in contact with the A of the AB 3 molecule. See diagram for correction.