Equilibria and Le Chatelier's Principle + Equilibrium constant (Kc) Flashcards
Features of dynamic equilbrium.
- the forward and backward reactions happen at equal rates
- the concs of the reactants and products are constant.
- occurs in closed systems - no substances can go in or out. this means that nothing will be able to influence the reaction
What is Le Chatelier’s Principle?
When a system is subject to change, the system will alter to lessen the effect of that change.
Why is Le Chatelier’ s Principle useful?
in industry: able to alter confitions to maximise the yield of desired product –> less waste
Changing temperature
Increase temp: equilibrium shifts to the endothermic reaction. increases the yield of endothermic products
Decrease temp: equilibrium shifts to the exothermic reaction. increases the yield of exothermic products
Change pressure
Increase pressure: equilibrium shifts to the side with the fewer moles. increases the yield on this side.
Decrease pressure: equilibrium shifts to the side with the most moles. increases the yield on this side.
Changing concentration
Increase conc of reactants: equilibrium shifts to the right to make more products
Decreasing concs of products: equilibrium shifts to the left to reform the reactants.
Catalysts
Does not affect equilibrium position bc they affect the forward and backward reactions equally.
However, allows equilibrium to be reached faster.
**Adding a catalyst allows a lower temperature to be used –> lowers cost
Catalysts allow the rate of the forward/backward reaction to increase.
What is Kc and what does it look like?
products/reactants
kc indicates the position of equilibrium for a reaction at a certain temperature.
temperature will only affect Kc, NOTHING ELSE.
.
units = mol2 dm-6
Answer: A
(need to add solution from ss on phone)
