Equilibria Flashcards
Dynamic equilibria
When a reversible reaction is carried out in a closed system
What makes a system dynamic
When the reactants are being converted at the same rate as the products
When you can’t see any change but reactions are still happening in both directions
What makes a system in dynamic equilibrium
When:
The concentration of reactions and products remain constant
The rate of forward and reverse reactions are the same
Dynamic equilibrium definition
The equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction
Le chateliers principle
“If a factor affecting the position of an equilibrium is altered, the position of the equilibrium moves in the direction to minimise the effect of the change”
How does a catalyst affect attainment of equilibrium
A catalyst speeds up how fast equilibrium is reached and doesn’t affect the position of equilibrium
Which side does a catalyst affect
It affects the rate of forwards and backwards equally
The effect of concentration
A change in concentration of reactants or products will result in the position of equilibrium shifting to counteract the change
The effect of pressure
Changing pressure will only affect if gases are present
Increasing will shift the position to side with less moles
Decreasing will shift the position to the side with more moles
What’s the effect of decreasing temperature on equilibrium
The system doesn’t like change and increases temperature by releasing heat
The position of equilibrium shifts towards he exothermic side
The effect of increasing temperature on equilibrium
The system opposes the change and decreases the temperature by taking in heat
The position of equilibrium shifts towards the endothermic side
The Haber process conditions
450 degrees Celsius
Iron catalyst
20000KPa
670K
Why is 670 k used instead of a lower temperature
It’s low enough to permit a high ish yield
It’s high enough for the reaction to happen fast enough to be cost effective
Why is 200 atmospheres used
Low enough for reasonable cost
High enough for acceptable yields
Production of ethanol conditions
570k
6500KPa
Phosphoric acid catalyst
Yield of haber process
15%
Yield of ethanol production
5%
Yield of methanol
5%
Methanol production conditions
Equilibrium constant
The ratio of concentration of products to reactants at a fixed temperature
