Question 1

What is the integrated rate law?

Accepted Answer

The integrated rate law expresses concentration as a function of time for a given reaction order. For first order: [A] = [A]₀·e^(−kt). For second order: 1/[A] = 1/[A]₀ + kt. For zero order: [A] = [A]₀ − kt.

Question 2

How do you determine reaction order from experimental data?

Accepted Answer

Plot concentration data in three ways: [A] vs time (zero order gives a straight line), ln[A] vs time (first order gives a straight line), and 1/[A] vs time (second order gives a straight line). The plot that is linear identifies the order, and the slope gives the rate constant k.

Question 3

What is the half-life of a first order reaction?

Accepted Answer

For a first order reaction, the half-life is t½ = ln(2)/k = 0.693/k, and it is independent of the initial concentration. For zero order, t½ = [A]₀/(2k). For second order, t½ = 1/(k[A]₀), which depends on initial concentration.

Order	Integrated Rate Law	Linear Plot	Half-Life	Units of k
Zero	[A] = [A]₀ − kt	[A] vs t	[A]₀ / 2k	mol·L⁻¹·s⁻¹
First	ln[A] = ln[A]₀ − kt	ln[A] vs t	ln(2) / k	s⁻¹
Second	1/[A] = 1/[A]₀ + kt	1/[A] vs t	1 / (k[A]₀)	L·mol⁻¹·s⁻¹