Equilibrium Flashcards
When has equilibrium been reached?
When the forward and backward reactions occur at the same rate
How do you know if a reaction can be at equilibrium?
Equilibrium reactions will always have a double arrow (⇌)
What is Kc and what do Kc expressions tell us?
Kc = equilibrium constant
Kc expressions tell us whether there are more products or reactants being formed in an equilibrium reaction
What are the units for Kc?
There are none
What is the only state Kc can work for?
Gases
What does [___] mean?
Concentrations of ___
What is the Kc formula?
Kc = [products] / [reactants]
What happens if there is a number in front of a molecule in Kc expressions?
The number turns into a power
Eg, [2NO(g)] becomes [NO(g)]^2
What do you do if there is a solid or liquid in a Kc expression?
Ignore and eliminate it
What will the Kc value tell us?
The ratio of [products] to [reactants]
What can and can’t a Kc tell us?
How far a reaction has proceeded but not how fast
What are Kc values dependent on?
Temperature (must always remain constant)
What do the numerator and denominator values of Kc tell us?
A higher numerator value means there are more products being formed than reactants, so therefore a forward reaction is favoured
A higher denominator value means there are more reactants being formed than products, so therefore a backward reaction is favoured
When is a Kc value large or small and what reactions will that favour?
Kc equals:
- Large if it is >1 and will favour the forward reaction
- Small if it is <1 and will favour the backward reaction
What are the factors affecting equilibrium?
Concentration, temperature, pressure and catalysts
