A2.1 How Fast?

Question 1

Rate equation

Answer 1

Rate = k [A] [B]

Orders of reactants = power of

Question 2

Zero order

Answer 2

Change in concentration of X has no effect on rate

Question 3

First order

Answer 3

Concentration of X is directly proportional to rate

Question 4

Second order

Answer 4

Change in rate is proportional to the square of change in conc

Question 5

Gradient of line - concentration-time graph

Answer 5

Rate of reaction

Question 6

Half life

Answer 6

Time taken for concentration to decrease by half

Question 7

If half life is constant…..

Answer 7

First order

Question 8

Using half life to calculate k

Answer 8

K = ln 2 /half life

Question 9

Gradient - rate-conc graphs

Answer 9

First order - equal to rate constant

Question 10

Collecting rates data - colorimeter

Answer 10

1)make up series of known concentration
2)measure absorbance of each
3)plot graph

Question 11

Collecting rates data - continuous monitoring method

Answer 11

Gas collection - gas that can be measured

Mass loss over time - gas that can be released safely

Question 12

Initial rates method

Answer 12

1)carry out several experiments changing conc each time
2)measure initial rate at T=0
3)measure time for visible change observed e.g. colour or precipitate
4)plot rate/conc graph

Question 13

Rate determining step

Answer 13

Slowest step