A2 equilibria. Flashcards
Kc expression.
Products/reactants
W/ the mole amounts as the indices/power.
Units calculation for Kc.
Substitute mol dm^-3 into the Kc expression.
Homogeneous equilibrium.
All species are in the same state.
Heterogeneous equilibrium.
Species with different states or phases
Solids and liquids are omitted from the Kc expression (constant concentrations)
Only gas or aqueous included.
Calculations of equilibrium amounts.
Practice ICE method.
Mole fraction meaning and calculation.
Number of moles of gas A/total number of moles in gas mixture.
Partial pressure meaning and calculation.
The contribution that the gas makes towards the total pressure
Pp(A)=mole fraction of A x total pressure.
Kp expression.
Written same way as Kc but with p in front of brackets
kPa, Pa or atm
Only includes gases.
Meaning of K value.
K=1, halfway between reactants and products
K=100, in favour of products
K=1x10^-2, in favour of reactants.
Effect of temperature of constant K on exothermic reactions.
If forward reaction exothermic:
-Increasing temperature=constant decreases
-Raising temperature=decreases equilibrium yield of products.
-P of E shifts to the left
Explanation of equilibrium shift in exothermic reactions.
Effect of temperature on an endothermic reaction.
Equilibrium constant(Kp) increases with increasing temperature
Higher temp= higher eq yield of products
Eq shifts to the right.
Explanation of equilibrium shift in endothermic reactions.
Effect of changes in concentration and pressure on equilibrium constants.
Does not affect the values
The equilibrium only shifts= no value changes.
Explanation of constant K values at changing concentrations and pressures.
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