The Equilibrium constant ( A-Level ) Flashcards
What is partial pressure?
Each gas’s contribution to the total pressure.
How would you calculate the partial pressure of a gas?
Partial pressure p = mole fraction x total pressure.
What is the mole fraction?
Mole fraction of gas X = number of moles of gas X in the mixture ÷ total number of moles of gas in the mixture.
How is a reaction represented?
A reaction is represented by aA(g) + bB(g) ⇌ cC(g) + d.
How do you calculate the units for Kp?
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.
What is the effect of increasing temperature on Kp for an endothermic reaction?
Equilibrium shifts to the ‘right’, so partial pressures of products increase, thus Kp increases.
What is the effect of increasing the overall pressure on Kp for this reaction?
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.
What will be the kinetic effect of increasing the temperature and pressure for any reaction?
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.
