3.1.10 Equilibrium constant Kp for homogenous system

Question 1

catalyst on the equilibrium constant

Answer 1

catalyst can affect the rate of attainment of equilibrium, it does not affect the value of the equilibrium constant.
- a catalyst speeds up forward and reverse reaction /rate which equilibrium

Question 2

derive partial pressure from mole fraction and total pressure

Answer 2

• total pressure in reaction - sum all pressures individual gases (Partial pressures)
  calculate partial pressure :
  1. total pressure, sum all pressures - plug in pressures in question - if one product has 1 mol of 263 other also 1 mol of 263
  2. solve equation

Question 3

Mole Fractions

Answer 3

• mole fraction - is a proportion (Fraction) of a gas in a gas mixture
• mole fraction of a gas= number of moles of gas / total number of moles of gas in mixture
• partial pressure = mole fraction of gas x total pressure in mixture

Question 4

perform calculations involving Kp

Answer 4

• Kp - equilibrium constant for an equilibrium reaction invovling gases (pp)
  -eE + fF -> gG + hH
• Kp= (PG)g (PH)h / (PE)e (PF)f
• units - kPa (cancel out)

Question 5

predict the qualitative effects of changes in temperature on the position of equilibrium and Kp value

Answer 5

temperature :
- Kp only valid for one temperature - change temp, change pressures, kp
- temp change causes equilibrium to shift right - Kp increase
-temp change causes equilibrium to shift left - Kp decrease
- increase temp - equilibrium shifts in the endothermic direction (to oppose an increase in temp) will decrease.
- decrease temp - equilibrium shifts in exothermic direction, kp increase
expression e.g. - Kp= (Pso3)2 / (Po2) x (Pso2)2

Question 6

predict the qualitative effects of changes in pressure on the position of equilibrium

Answer 6

uneffected by any changes in pressure