The Equilibrium Constant (KP) - Physical 2

Question 1

What is partial pressure

Answer 1

Each gas’s contribution to the total pressure

Question 2

How would you calculate the partial pressure of a gas?

Answer 2

Partial pressure p = mole fraction x total pressure

Question 3

What is the mole fraction?

Answer 3

Mole fraction of gas X = number of moles of gas X in the mixture ➗ total number of moles of gas in the mixture

Question 4

A reaction is represented by aA (g) + bB (g) ⇌ cC (g) + dD (g), what Kp for the system?

Answer 4

check

Question 5

How do you calculate the units for Kp?

Answer 5

Write out the units for the partial pressures in the same arrangement as the Kp equation and cancel out/multiply together.
Usually in Pa, kPa, atm etc. DO NOT CHANGE UNITS

Question 6

What is the effect of increasing temperature on Kp for an endothermic reaction?

Answer 6

Equilibrium shifts to the right, so partial pressures of products increase, so Kp increases

Question 7

What is the effect of increasing the overall pressure on Kp for this reaction?

Kp = pC^c pD^d / pA^a pB^b

Answer 7

Pressure does not affect Kp as, if moles of gas are not the same on each side), either top or bottom of Kp expression will have a total pressure term that does not cancel.

Kp = pC^c pD^d / pA^a pB^b

Question 8

What will be the kinetic effect of increasing the temperature and pressure for any reaction?

Answer 8

Increasing both will increase the rate of reaction as: Temperature - many more particles have energy greater than or equal to the activation energy → more successful collisions per second
Pressure - more particles in the same volume → more successful collisions per second.