Section 7 - Rate Equations and Kp

Question 1

Define rate of reaction

Answer 1

Change in amount of reactant or product per unit time.

Question 2

What is the rate equation?

Answer 2

Rate = k[A]^m[B]ⁿ

where m and n are the orders of reaction

Question 3

What is the overall order of reaction?

Answer 3

m+n

Question 4

Do you know how to work out the order of reaction?

Answer 4

Yes

Question 5

What is the rate constant dependent on?

Answer 5

Temperature

Question 6

What is the initial rate of reaction?

Answer 6

The rate right at the start of the reaction.

Question 7

What are the 4 ways of measuring reaction rate?

Answer 7

• Gas volume
• Loss of mass
• Colour change
• Change in pH

Question 8

What is the order of reaction when gradient is 0 on a rate-concentration graph?

Answer 8

0

Question 9

What is the order of reaction when gradient is constant on a rate-concentration graph?

Answer 9

1

Question 10

What is the order of reaction when gradient is increasing on a rate-concentration graph?

Answer 10

2

Question 11

What is the rate-determining step?

Answer 11

The slowest step in a multi-step reaction.

Question 12

What has to be included in the rate determining step?

Answer 12

The elements in the rate equation.

Question 13

What does each symbol in the Arrhenius equation mean?

k=Ae^-Ea/RT

Answer 13

k = rate constant

A = the Arrhenius constant

Ea = activation energy (J)

R = gas constant

T = temperature (K)

Question 14

What is the Arrhenius equation (k = Ae^-Ea/RT) in y=mx+c form?

Answer 14

lnk = -Ea/RT + lnA

Question 15

What are the y and x-axis in an Arrhenius plot?

Answer 15

x-axis = 1/T

y-axis = lnk

Question 16

What is the total pressure of a gas?

Answer 16

The sum of all the partial pressures of the individual gases

Question 17

What is the formula for mole fraction?

Answer 17

Number of moles of gas/Total number of moles of gas in the mixture

Question 18

How do you calculate partial pressure of a gas?

Answer 18

Mole fraction of gas x Total pressure of mixture

Question 19

What is the formula for Kp for the equilibrium:

aA + bB <–> dD +eE

Answer 19

(pD)^d(pE)^e/(pA)^a(pB)^b

Question 20

What is Kp?

Answer 20

The equilibrium constant for a reversible reaction where all the reactants and products are gases.

Question 21

What direction does the equilibrium shift in if you increase the pressure?

Answer 21

Side with the fewer moles

Question 22

What direction does the equilibrium shift in if you increase the temperature?

Answer 22

Endothermic direction

Question 23

What direction does the equilibrium shift in if you add a catalyst?

Answer 23

It doesn’t move.