AC2: Reaction Kinetics II

Question 1

What order is A if the concentration doubles and the rate also doubles

Answer 1

First order

Question 2

What order is A if the concentration doubles but the rate quadruples

Answer 2

Second order

Question 3

When the equation is Rate=[A][B], what is the overall order, and what is the order for A and what is the order for B

Answer 3

Second order overall since A and B are both first order (1+1=2). First order in concentration of A and first order for concentration of B

Question 4

What is the rate equation, involving A & B, if the overall order was 4 and the order of A was second

Answer 4

Rate=k[A]^2[B]^2
Both are second order since 2+2=4

Question 5

When solving k what is always the most important thing to remember

Answer 5

The unit

Question 6

What would happen to the rate if [A] was tripled
Rate=k[A]^2

Answer 6

Rate increases x9

Question 7

What would happen to the rate if both A and B were doubled
Rate=k[A][B]^2

Answer 7

If A doubles the rate doubles, x2, and if B doubles the rate quadruples, x4, so rate increases by a factor of 8

Question 8

What is the name of the slow step in chemical reactions

Answer 8

Rate determining step

Question 9

What are the 2 rules of stepwise mechanisms

Answer 9

• The rate equation only includes reacting species involved in the rate determining step
• The orders in the rate equation match the number of species involved in the RDS

Question 10

A->B->C reaction, what is the name of B, something that is created and destroyed in the reaction

Answer 10

Intermediate

Question 11

When creating your own mechanism, what is the final step to do to check it’s the same as the chemical equation

Answer 11

Add up the LHS and add up the RHS

Question 12

What is the name of a reactant that isn’t used up in the chemical equation but is regenerated in the final step of the mechanism

Answer 12

Catalyst