Rate Equations

Question 1

What is the rate equation? (1 mark)

Answer 1

⦾ Rate = k[A]^m[B]^n (1)

Question 2

What do [ ] mean? (1 mark)

Answer 2

⦾ conc. of whatever’s inside (1)

Question 3

What do the different components of the rate equation mean? (3 marks)

⦾ Rate = k[A]^m[B]^n

Answer 3

⦾ k - rate constant (1)
⦾ [A] and [B] - conc. of what’s inside (1)
⦾ ^m and ^n - order of reaction (1)

Question 4

What are reaction orders? (^m and ^n) (1 mark)

Answer 4

⦾ ^m and ^n - how conc. of A or B affects the rate (1)

Question 5

1. What is the order of reaction if [A] changes and the rate stays the same? (1 mark)
2. So, if [A] doubles, what happens to the rate? (1 mark)

Answer 5

1. Order of reaction with respect to A is 0/zero order with respect to A (1)
2. Stays the same (1)

Question 6

1. What is the order of reaction if rate is proportional to [A]? (1 mark)
2. So, if [A] doubles, what happens to the rate? (1 mark)

Answer 6

1. Order of reaction with respect to A is 1/first order with respect to A (1)
2. Doubles too (1)

Question 7

1. What is the order of reaction if rate is proportional to [A]^2? (1 mark)
2. So, if [A] doubles, what happens to the rate? (1 mark)
3. So if [A] triples, what happens to the rate? (1 mark)

Answer 7

1. Order of reaction with respect to A is 2/second order with respect to A (1)
2. Rate will be 2^2 = 4 X faster (1)
3. Rate will be 3^2 = 9 X faster (1)

Question 8

How can you calculate the overall order of the reaction?

Answer 8

⦾ m + n

e.g. m = 2, n = 1 2 + 1 = 3