Chapter 10 and 11 AS Flashcards
(12 cards)
Define the term dynamic equilibrium.
The rate of the forward reaction is equal to the rate of the reverse reaction, in a closed system.
So, concentration of reactants and products do not change.
Give an essential condition for an equilibrium mixture.
Equilibrium occurs in a closed system where reactants and products cannot escape.
(Or, macroscopic properties do not change with time)
State Le Chatelier’s Principle
If a change is made to a system at equilibrium, the system counteracts the change but shifting the position of equilibrium in the direction that reduces the effect of the initial change.
What happens to the position of equilibrium when temperatures increases?
Equilibrium shifts in the direction of the endothermic reaction to decrease the temperature.
What happens to the position of equilibrium when pressure increases?
Equilibrium shifts in the direction of the fewer gas moles to decrease the pressure.
In industry, why may the pressure be high in a reaction?
1) The high pressure increases the collision frequency, increasing the rate of reaction
2) A compromise pressure is made between an economically viable rate of reaction and a slightly lower yield of desired product from the equilibrium reaction
What effect does a catalyst have on the position of equilibrium?
No effect as catalysts affect the rates of forward and reverse reactions equally resulting in no effect.
It may help the reaction to reach equilibrium faster but it will not affect the position of equilibrium.
What is the value for Kc?
mol dm-3
What type of systems is Kc relevant for?
Homogeneous systems in equilibrium (reacts and products are in the same state)
What does Kc being greater or lesser than 1 suggest for the position of equilibrium?
Greater than 1 –> Shifted to the right
Lesser than 1 –> Shifted to the left
If Kc is exactly 1, then you have 50% products and 50% reactants so the position of equilibrium is sitting around the middle.
What condition affects the value of Kc?
Temperature ONLY
