1.9 Kinetics A2

Question 1

What is an order of reaction?

Answer 1

The order given to a reactant in a reaction show the extent to which it affects the rate of reaction. Reactants often affect the rate to different degrees.

Question 2

What change in rate would occur when you
- double
- triple
A 0 order reactant?

Answer 2

• Nothing

- Nothing

Question 3

What change in rate would occur when you
- double
- triple
A 1 order reactant?

Answer 3

• Doubles (x2^1)

- Triples (x3^1)

Question 4

What change in rate would occur when you
- double
- triple
A 2nd order reactant?

Answer 4

• Quadruples (x2^2)

- Nonuples (x3^2)

Question 5

How do you calculate the overall order of a reaction?

Answer 5

The sum of the individual orders of reactants. Eg. [H2]2[I2]1 would be a third order reaction

Question 6

How are rate equations written?

Answer 6

Rate = K[A]m[B]n

Where K is the rate constant

Question 7

What is the rate constant affected by?

Answer 7

Temperature and catalysts.

Question 8

What does a large rate constant correlate to?

Answer 8

A fast reaction

Question 9

How do we calculate rate constant

Answer 9

K= initial rate of reaction / (concentration of reactants)^order of this reactant

Question 10

What units will the rate constant be for a first order reaction?

Answer 10

S^-1

Question 11

What units will the rate constant be for a

second order reaction?

Answer 11

Mol-1dm3s-1

Question 12

What is Arrhenius’ equation?

Answer 12

K=Ae^-Ea/RT

• K is rate constant
• A is frequency factor of Arrhenius constant
• e is natural log base
• Ea is activation energy (KJmol-1)
• R is gas constant (JMol-1K-1)
• T is absolute temperature in Kelvin

Question 13

What is e^-Ea/RT?

Answer 13

The probability that a reaction will occur (the number of particles with E>Ea)

Question 14

What is the natural log version of Arrhenius’ equation?

Answer 14

ln(K) = (-Ea/R) x (1/T) + ln(A)

Question 15

What is the slowest step in a reaction known as?

Answer 15

The rate determining step

Question 16

Which species are in the rate equation (RDS)

Answer 16

Species involved in the rate determining step and the reactants in the steps before this

Question 17

If a reactant is zero order is it involved in the rate determining step?

Answer 17

No it is not

Question 18

If a reactant is second order, is it likely to be in the RDS?

Answer 18

No it is less likely

Question 19

What does the gradient in an Arrhenius graph represent?

Answer 19

-Ea/R

Question 20

What does the y intercept in an Arrhenius graph represent?

Answer 20

ln(A)

Question 21

What is along the y and x axis of an Arrhenius graph?

Answer 21

X = 1/T (in Kelvin)
Y = ln(k)