5A The Rate Equation Review Questions with
Answers 2024 Test
What is the rate of reaction? - Correct Answer The change in concentration of a
reactant (or product) in a given time
What is the order? - Correct Answer The power to which the concentration of a
reactant is raised in the rate equation
What is the overall order? - Correct Answer The sum of the individual orders of the
reactants in the rate equation: m + n
What is the rate constant? - Correct Answer k- the constant that links the rate of
reaction with the concentration of the reactants raised to the powers of their orders
in the rate equation
What is the rate equation? - Correct Answer For a reaction: A + B-> C with orders
m for A and n for B, the rate equation is given by:
Rate= k[A]m[B]n
Describe each component of the rate equation - Correct Answer Rate= k[A]m [B]n
k= rate constant
m is the order with respect to A
n is the order with respect to B
What is zero order? - Correct Answer Rate is unaffected by changes in
concentration
Rate ∝ [A]⁰=1
What is first order? - Correct Answer 'a reactant is first order with respect to a
reactant when..'
Rate is directly proportional to concentration
If we double the conk then the rate doubles
Rate∝ [A]¹
What is second order? - Correct Answer Rate is proportional to concentration²
If we double the concentration then the rate increases by a factor of 2²... it
quadruples
Rate ∝ [A]²
, How to calculate the rate constant - Correct Answer k= rate/[A]n[B]m
When deducing orders from experimental data (initial rates data) what structure
should I follow? - Correct Answer Comparing exits 1 and 2 [D] and [F] are constant
[E] x 2, rate x 2
Rate ∝ [ ]² so the reaction is second order wt E
[R] x 2, rate unchanged.
Rate is independent of [R] so reaction is zero order wt r
What if you are comparing two experiments where not everything is constant
structure? - Correct Answer Considering exit 2 and 4, [R] is constant,
[P] x 2 and [Q] x 2, rate x 4
Given we knew the reaction was x order wt P, doubling [P] should double rate,
doubling [Q] subsequently also doubled rate further so..../or made no impact on rate
of reaction
What is the [reactant] vs. time graph for zero order and what are the two ways you
can find rate constant? - Correct Answer Straight line w/ negative gradient.
Reaction rate does not change at all during course of reaction.
Value of gradient = rate constant k
as [reactant]°
Convert into a rate vs. [reactant] graph, should be a straight horizontal line with k=
'y-intercept'
Draw a rate vs. [reactant] graph for zero order - Correct Answer k = 'y-intercept'
What is the [reactant] vs. time graph for first order and what are the three ways to
find rate constant? - Correct Answer Downwards curve with a decreasing gradient
over time
Time for concentration of the reactant to halve is constant
(half-life)
then using the half-life use
k=ln2/t¹/₂ (more accurate than tangent) units- s-1
OR
2) Deduce rate at a particular conk and substitution into rate equation
(add up your rates at different points on the graph and average
3) Using a rate-concentration graph
Plotting rate values found in above against concentration will give a straight line
whose gradient=k
What is half-life? What is first order's half-life and second orders? - Correct Answer
t¹/₂The time taken for the concentration of a reactant to decrease by half
Answers 2024 Test
What is the rate of reaction? - Correct Answer The change in concentration of a
reactant (or product) in a given time
What is the order? - Correct Answer The power to which the concentration of a
reactant is raised in the rate equation
What is the overall order? - Correct Answer The sum of the individual orders of the
reactants in the rate equation: m + n
What is the rate constant? - Correct Answer k- the constant that links the rate of
reaction with the concentration of the reactants raised to the powers of their orders
in the rate equation
What is the rate equation? - Correct Answer For a reaction: A + B-> C with orders
m for A and n for B, the rate equation is given by:
Rate= k[A]m[B]n
Describe each component of the rate equation - Correct Answer Rate= k[A]m [B]n
k= rate constant
m is the order with respect to A
n is the order with respect to B
What is zero order? - Correct Answer Rate is unaffected by changes in
concentration
Rate ∝ [A]⁰=1
What is first order? - Correct Answer 'a reactant is first order with respect to a
reactant when..'
Rate is directly proportional to concentration
If we double the conk then the rate doubles
Rate∝ [A]¹
What is second order? - Correct Answer Rate is proportional to concentration²
If we double the concentration then the rate increases by a factor of 2²... it
quadruples
Rate ∝ [A]²
, How to calculate the rate constant - Correct Answer k= rate/[A]n[B]m
When deducing orders from experimental data (initial rates data) what structure
should I follow? - Correct Answer Comparing exits 1 and 2 [D] and [F] are constant
[E] x 2, rate x 2
Rate ∝ [ ]² so the reaction is second order wt E
[R] x 2, rate unchanged.
Rate is independent of [R] so reaction is zero order wt r
What if you are comparing two experiments where not everything is constant
structure? - Correct Answer Considering exit 2 and 4, [R] is constant,
[P] x 2 and [Q] x 2, rate x 4
Given we knew the reaction was x order wt P, doubling [P] should double rate,
doubling [Q] subsequently also doubled rate further so..../or made no impact on rate
of reaction
What is the [reactant] vs. time graph for zero order and what are the two ways you
can find rate constant? - Correct Answer Straight line w/ negative gradient.
Reaction rate does not change at all during course of reaction.
Value of gradient = rate constant k
as [reactant]°
Convert into a rate vs. [reactant] graph, should be a straight horizontal line with k=
'y-intercept'
Draw a rate vs. [reactant] graph for zero order - Correct Answer k = 'y-intercept'
What is the [reactant] vs. time graph for first order and what are the three ways to
find rate constant? - Correct Answer Downwards curve with a decreasing gradient
over time
Time for concentration of the reactant to halve is constant
(half-life)
then using the half-life use
k=ln2/t¹/₂ (more accurate than tangent) units- s-1
OR
2) Deduce rate at a particular conk and substitution into rate equation
(add up your rates at different points on the graph and average
3) Using a rate-concentration graph
Plotting rate values found in above against concentration will give a straight line
whose gradient=k
What is half-life? What is first order's half-life and second orders? - Correct Answer
t¹/₂The time taken for the concentration of a reactant to decrease by half
