Physical - 1.10 Kp

Question 1

How would you calculate a mole fraction?

Answer 1

A mixture contains 1.42g of nitrogen and 2.41g of oxygen. Calculate the mole fraction of the gases in this mixture.

Moles of N2 = 1.42/28 = 0.0507 mol
Moles of O2 = 2.41/32= 0.0753 mol
Total moles of gas = 0.0507+0.0753=0.126 mol
Mole fraction of N2 = 0.0507/0.126=0.402
Mole fraction of O2 = 0.0753/0.126=0.598

Question 2

How can the partial pressure of a component be calculated?

Answer 2

By multiplying the total pressure of the mixture by the mole fraction of that component

Question 3

How is Kp expressed?

Answer 3

Kp = p(C)c x p(D)d / p(A)a x p(B)b

Where p(A)a is the partial pressure of A raised to the power of a

Question 4

What are the units for Kp?

Answer 4

kPa or MPa

Question 5

What is the equation for partial pressure?

Answer 5

Partial pressure = mole fraction x total pressure

Question 6

How is the mole fraction found in Kp?

Answer 6

Using:

I
C
E

Question 7

What is Kp affected by?

Answer 7

Equilibrium constant Kp is affected by changes in temperature but it is not affected by changes in pressure, the presence of a catalyst or changes in concentration or amount of substances present in the mixture.

This is the same for all equilibrium constants which are on our particular temperature and are not affected by changes in other quantities.