Rate equations

Question 1

Define rate.

Answer 1

Change of concentration of products/reactants per unit time.

Question 2

What are the units of rate.

Answer 2

mol/dm³

Question 3

On a conc-time graph, what is the gradient of a tangent equal to?

Answer 3

Rate at that concentration.

Question 4

What is the rate equation?

Answer 4

rate=k[A]^m [B]^n

Question 4

What is k?

Answer 4

The rate constant.

Question 5

How is k measured?

Answer 5

Experimentally.

Question 6

What does the value of k depend on?

Answer 6

Temperature.

Question 7

What are the units of k?

Answer 7

Dependent on reaction.

Question 8

What are m and n?

Answer 8

Order of reaction.

Question 9

What can the order of reaction be?

Answer 9

»0
»1 (first)
»2 (second)

Question 10

What is overall order of a reaction?

Answer 10

Sum of all the powers/orders.

Question 11

What effect does concentration have on rate at 0 order?

Answer 11

No effect.

Question 12

How is 0 order written?

Answer 12

[X]⁰ - not written.

Question 13

What effect does concentration have on rate at first order?

Answer 13

Linear effect.

Question 14

How is first order written?

Answer 14

[X]¹ = [X]

Question 15

What effect does concentration have on rate at second order?

Answer 15

Quadratic effect.

Question 16

How is second order written?

Answer 16

[X]²

Question 17

Describe a rate-concentration graph for 0 order.

Answer 17

Straight horizontal line.

Question 18

Describe a rate-concentration graph for first order.

Answer 18

Straight positive diagonal line.

Question 19

Describe a rate-concentration graph for second order.

Answer 19

Curved increasing line.

Question 20

Describe a concentration-time graph for 0 order.

Answer 20

Straight negative diagonal line.

Question 21

Describe a concentration-time graph for first order.

Answer 21

Curved decreasing shallow line.

Question 22

Describe a concentration-time graph for second order.

Answer 22

Curved decreasing steep line.

Question 23

What happens to rate concentration of temperature increases?

Answer 23

Rate constant increases exponentially.

Question 24

What is the Arrhenius equation?

Answer 24

k= Ae^(-Ea/RT)

Question 25

What is A?

Answer 25

Arrhenius constant.

Question 26

What are the units of A?

Answer 26

Same as k.

Question 27

What is e?

Answer 27

Euler’s number.

Question 28

What are the units of e?

Answer 28

No units.

Question 29

What is Ea?

Answer 29

Activation energy.

Question 30

What are the units of Ea?

Answer 30

J/mol

Question 31

What is R?

Answer 31

Gas constant.

Question 32

What are the units of R?

Answer 32

J/K/mol

Question 33

What is T?

Answer 33

Temperature.

Question 34

What are the units of T?

Answer 34

K

Question 35

What effect does increasing temperature have on rate/k?

Answer 35

Increases rate/k.

Question 36

What effect does adding a catalyst have on rate/k?

Answer 36

Increases rate/k.

Question 37

What is the rearranged Arrhenius equation using natural logs?

Answer 37

lnk= (-Ea/RT) + lnA

Question 38

If graph of Arrhenius equation is drawn, what is y?

Answer 38

lnk

Question 39

If graph of Arrhenius equation is drawn, what is m?

Answer 39

-Ea/RT

Question 40

If graph of Arrhenius equation is drawn, what is x?

Answer 40

1/T

Question 41

If graph of Arrhenius equation is drawn, what is c?

Answer 41

lnA

Question 42

How can activation energy be worked out from Arrhenius equation graph?

Answer 42

gradient x -R