10. Equilibrium I Flashcards
(14 cards)
Define Le Chateliers principle
When a reaction at equilibrium is changed, it will seek to counteract that change
What are 3 features of a system in a state of dynamic equilibrium?
Forward and backward reaction are happening at the same rate
All reactants and products are present
Concentration of reactants and products remains constant
Is equilibria reached in an open or closed system?
Closed system - no chemical can enter ot leave the system
Give the impact of increasing temperature at equilibrium
Equilibrium shifts ( right or left) to favour the endothermic reaction to try and cool the system down
–> the activation energy for the reaction in the endothermic direction is greater than that for the reaction in the exothermic direction and reactions with high activation energies are more sensitive to temperature changes than reactions with lower activation energies.
Give the impact of decreasing temperature at equilibrium
Equilibrium shifts ( either right or left) to favour the exothermic reaction to try and increase temperature of system
Give the impact of increasing pressure at equilibrium
Equilibrium shifts to favour the reaction that produces the least amount of gas molecules
Give the impact of increasing reactant concentration at equilibrium
equilibrium favours the forward reaction to lower the concentration of reactants
Give the impact of using a catalyst
No effect, only increases rate
What are the two types of equilibrium you can have
Industrial - flow
Pharmacy - batches
Equilibrium in industry is a….
compromise. Its a compromise between rate of reaction and yeild e.g. very high pressures aren’t safe and expensive to maintain. High temperature increase rate but often deccrease yeild.
Give the homogenous Kc constant equation
[concentration of products] / [concentration of reactants] and the chemicals are to the power of the big number
all reactants and products in equation
Give the heterogenous Kc constant equation
[concentration of products] / [concentration of reactants] and the chemicals are to the power of the big number
not include solids or pure liquids - their concentration is constant
What is the only factor that changes the Kc value
Temperature
(changing concentration, pressure, catalyst has no effect on Kc constant)
How do you work out moles of chemicals in a reaction at equilibrium
ICE
I- write out initial moles
C- work out the change in moles for the one they have given you. If its on the same side its, + and if its on different side its -. If its 2 initial mole, times the difference by 2
E - mole at equilibrium now calculated
