Equilibria (R2.3) Flashcards
(18 cards)
What’s equilibrium law expression?
products/reactants
What does it mean when Kc is equal to 1?
the concentration of both products and reactants is equal
What does it mean when Kc is bigger than 1?
the equilibrium favours forward reaction, there are more products
What does it mean when Kc is smaller than 1?
equlibrium favours reverse reaction, there are more reactants
What are the main properties of the equilibrium?
- requires closed system
- rate of forward reaction = rate of reverse reaction
- can be reached from many starting concentrations
What’s the Chatelier’s principle?
When a system at equilibrium is subjected to a change, the system will respond to minimise the effect of the change
What’s equilibrium constant?
ratio between [products] and [reactants] at equilibrium
What’s the effect of higher concentration of products/reactants on equilibrium and Kc?
products: shifts left
reactants: shifts right
Kc: no change
What’s the effect of increased temperature on equilibrium in endothermic/exothermic reaction and on Kc?
endothermic: shifts right
exothermic: shifts left
Kc: increases
What’s the effect of increased pressure on equilibrium and Kc?
- it will move to the side with fewer gas molecules
Kc: no change
What’s the effect of catalyst on the equilibrium?
the effect of cthe atalyst cancels out, so there is no shift
What’s the reaction quotient (Q)?
ration of concentrations of products to reactants at any point
What does it mean when Q = Kc?
that system is at equilibrium
What does it mean when Q is smaller than Kc?
there is not enough product and it needs to shift right
What does it mean when Q is bigger than Kc?
there is not enough reactant and it needs to shift left
What’s the formula for reaction quotient?
same as Kc, products/reactants
What’s the ICE table used for and how does it look?
to determine concentrations at equilibrium
What’s the expression for Kc derived from data booklet formula for Gibbs free energy?
