Orders, Rate Equations, And Rate Constants

Question 1

What is the definition of rates of reactions?

Answer 1

The concentration of reactants or products reacted/produced per unit time

Question 2

What is the equation for rate of reaction? Units?

Answer 2

Rate (moldm-3 s-1) = change in concentration (moldm-3) change in time (s)

Question 3

What is the shorthand for concentration?

Answer 3

[x]

Question 4

What are the 3 common orders in an order of reaction?

Answer 4

Zero order (0)
First order (1)
Second order (2)

Question 5

What does the zero order mean?

Answer 5

When the concentration of a reactant has no effect on the rate, the reaction is zero order with respect to the reactant

[x]^0

Question 6

What are the two factors of a zero order reaction?

Answer 6

1. Any number raised to the power zero is 1.
2. Concentration does not influence the rate.

Question 7

What is the first order in the order of reaction?

Answer 7

A reaction is first order with the respect to a reactant when the rate depends its concentration raised to the power of 1

[x]^1

Question 8

What are the two factors of a first order reaction?

Answer 8

1. If the concentration of x is doubled, the reaction rate increases by a factor of 2^1 = 2
2. If the concentration of x is tripled, the reaction rate increases by a factor of 3^1 = 3

Question 9

What is the second order in the order of reaction?

Answer 9

A reaction is second order with respect to a reactant when the rate depends on its concentration raised to the power of 2

[x]^2

Question 10

What are the two factors in a second order reaction?

Answer 10

1. If the concentration of x is doubled, the reaction rate increases by a factor of 2^2 = 4
2. If the concentration of A is tripled, the reaction rate increases by a factor of 3^2 = 9.

Question 11

What is the rate equation?

Answer 11

Rate = k [A]^ [B]^

Question 12

How do yo work out the overall order?

Answer 12

Sum of orders with respect to each reactant.

Question 13

How do yo work out the overall order?

Answer 13

Sum of orders with respect to each reactant.

Question 14

What is the equation to calculate k?

Answer 14

K = rate / [A]^ [B]^

Question 15

How can you figure out what reactants have what order?

Answer 15

• Zero order: no matter what you do to the concentration, the rate does not change.
• 1st order: whatever you do to the concentration, the rate changes by the sane factor.
• 2nd order: whatever you do to the concentration, the rate changes by the same factor squared.