AP Unit 8 Review

Step 1: NO(g)  +  O₃(g)   -->  NO₂(g)  +  O₂(g)

Step 2:  NO₂(g)  +  O(g)  --> NO(g)  +  O₂(g)

A reaction mechanism for the destruction of ozone, O₃(g), is represented above. In the overall reaction, NO(g) is best described as

• an inhibitor

• a catalyst

• a reactant

• an intermediate

• a product

2A(g)  +  B(g)  --> 2C(g)   When the concentration of substance B in the reaction is doubled, all other factors being held constant, it is found that the rate of the reaction remains unchanged.  The most probably explanation for this observation is that:

• A)   The order of the reaction with respect to substance B is 1

• A)   Substance B is not involved in any of the steps in the mechanism of the reaction

• A)   Substance B is not involved in the rate-determined step of the mechanism, but is involved in subsequent steps

• A)   Substance B is probably a catalyst, and as such, its effect on the rate of the reaction does not depend on its concentration

Tags

NGSS.HS-PS1-5

Step 1: Ce⁴⁺ + Mn²⁺  -->  Ce³⁺  +  Mn³⁺

  Step 2: Ce⁴⁺ + Mn³⁺  -->  Ce³⁺  +  Mn⁴⁺

Step 3: Mn⁴⁺ + Tl⁺  -->  Tl³⁺  +  Mn²⁺

The proposed steps for a catalyzed reaction between Ce⁴⁺ and Tl⁺ are represented above. The products of the overall catalyzed reaction are:

• Ce⁴⁺ and Tl+

• Ce³⁺ and Tl³⁺         

• Ce³⁺ and Mn³⁺           

• Ce³⁺ and Mn⁴⁺          

• Tl³⁺ and Mn²⁺  

Tags

NGSS.HS-PS1-2

NO₂(g)  +  CO(g)  -->  NO(g)  +  CO₂(g)  

The reaction between NO₂(g) and CO(g) is represented above. The elementary steps of a proposed reaction mechanism are represented below.

Step 1:  2NO₂(g)  -->  NO(g)  +  NO₃(g)                           (slow)

 Step 2:  NO₃(g)  +  CO(g)  -->  NO₂(g)  +  CO₂(g)            (fast)

 

            Which of the following is the rate law for the overall reaction that is consistent with the proposed mechanism?

• Rate = k [NO₂] [CO]        

• Rate = k [NO₂]²      

• Rate = k [NO₃] [CO]       

• Rate = k [NO₂] [NO₃] [CO]

Tags

NGSS.HS-PS1-5

Br₂(g)  +  2NO(g)  -->  2NOBr(g)

The reaction represented by the equation above has the following proposed mechanism

 

                        Step 1:   NO(g)  +  Br₂(g)  <-->  NOBr₂(g)             (fast)

                        Step 2:   NOBr₂(g)  +  NO(g)  -->  2NOBr(g)       (slow)

Based on the information, which of the following is the initial rate law for the reaction?

• Rate = k[Br₂] [NO]         

• Rate = k[Br₂] [NO]²       

• Rate = k[Br₂]² [NO]       

• Rate = k[NOBr₂] [NO]

Tags

NGSS.HS-PS1-5

2H₂(g)  +  2NO(g)  ®  N₂(g)  +  2H₂O(g)The experimental rate law for the reaction represented above is rate = k[H₂][NO]². Which of the following proposed mechanisms is consistent with the rate law?

• 
• 
• 
• 

Tags

NGSS.HS-PS1-5

Although the combustion of methane is a spontaneous process, a spark must be introduced in order to trigger the reaction. Which of the following statements provides the best explanation for why this is so?

• The spark provides the activation energy required to get the reaction started

• The hot chemicals from the flint catalyze the reaction

• The heat from the spark increases the activation energy for the reaction

• The heat from the spark decreases DE, making the reaction less exothermic

• The heat from the spark removed energy from the bonds in the methane molecules, thereby lowering the activation energy for the forward reaction.

Which of the following statements are associated with fast reaction rates?

I. Reactant molecules with weak bonds

II. High activation energy

III. A high percentage of collision orientations that can produce a reaction

• I only

• II only

• I and II only

• I and III only

• I, II, and III

Tags

NGSS.HS-PS1-4

Which of the following must be true for a reaction for which the activation energy is the same for both the forward and the reverse reaction?

• A catalyst is present

• The reaction order can be obtained directly from the balanced equation

• The reaction order is zero

Tags

NGSS.HS-PS1-4

What is collision theory?

• Molecules must collide in the correct orientation with enough energy to bond.

• Molecules need enough energy to collide and react.

• Atoms constantly collide and react.

• The minimum energy needed for atoms to react

Tags

NGSS.HS-PS1-5