# Quiz | Chemical Kinetics: Rate Laws

1

What is the rate of the following reaction: 2A + B → C?

$\frac{∆\left[\mathrm{A}\right]}{∆\mathrm{t}}$

A is a reagent and its stochiometric coefficient is 2. Reaction rate of a reagent:

α = stochiometric coefficient
[reagent] = concentration of the reagent (in mol.L-1)

2

What is the overall order of a reaction with a rate = k [A][B]?

0

1

2

3

The overall order of reaction is the sum of the orders of reaction of all the reactants

3

What are the units of the constant k in the rate of reaction = k [A][B] (concentration in mol.L-1) ?

s

mol-2.L2.s

mol-1.L1.s-1

mol-2.L2.s-1

The rate of reaction is in mol.L-1.s-1 and [A]2 [B] is in mol3.L-3   ⇒    k is in mol-2.L2.s-1

4

What is correct concerning the half-time of a first-order reaction?

t1/2 is independent of the initial concentration of the reactant

t1/2 is proportional to the initial concentration of the reactant

t1/2 is inversely proportional to the initial concentration of the reactant

None of the above

For a first-order reaction:

5

What is correct concerning the half-time of a second-order reaction?

t1/2 is independent of the initial concentration of the reactant

t1/2 is proportional to the initial concentration of the reactant

t1/2 is inversely proportional to the initial concentration of the reactant

None of the above

For a second-order reaction:

6

What is the relationship between [A] and t for a first-order reaction?

ln[A] = ln[A]0 + kt

$\frac{\left[\mathrm{A}\right]}{{\left[\mathrm{A}\right]}_{0}}$ = e-kt

$\frac{\left[\mathrm{A}\right]}{{\left[\mathrm{A}\right]}_{0}}$ = et

$\frac{1}{\left[\mathrm{A}\right]}$ = $\frac{1}{{\left[\mathrm{A}\right]}_{0}}$ + kt

For a first-order reaction:    = k [A]

After integrating:    ln [A] = ln [A]0 - kt   ⇒   $\frac{\left[\mathrm{A}\right]}{{\left[\mathrm{A}\right]}_{0}}$ = e-kt