✅10 - Equilibrium I Flashcards
What can reversible reactions reach?
Dynamic euqillibrium
As the reactants are used up, what happens to the forward reaction?
It slows down
When is dynamic equilibrium achieved?
When the forwards reaction is going at exactly the same rate as the backwards reaction and the amounts of reactants and products aren’t changing
What does dynamic equilibrium happen in?
A closed system
What is Kc?
The equilibrium constant
What does Kc give you an idea of?
How far to the left or right the equilibrium is
What is a homogeneous system?
A system in which everything is in the same physical state
What can Kc be worked out using?
The concentrations of reactants and products at equilibrium
Which reactants and products are included in Kc for homogeneous equilibria?
All of them
What is the equation for Kc?
[products]/[reactants]
What is a heterogeneous equilibria?
One in which not everything is in the same physical state
What is not included in the Kc expression for heterogeneous equilibria?
Pure liquids or solids
Why are solids not included in the Kc expression?
Because their concentration is constant
Why are pure liquids not included in the Kc expression?
Because their concentration is constant
Why aren’t catalysts included in the Kc expressions?
Because they don’t affect the equilibrium concentrations of the products or reactants
How do catalysts affect equilibrium?
They increase the rate at which equilibrium is reached
What is Le Chatelier’s principle?
If there is a change in concentration, pressure or temperature, the equilibrium will move to help counteract the change
If the position of equilibrium is altered, what will happen?
The amounts of products and reactants at equlibrium change
What happens if the concentration of a reactant is increased?
The equilibrium shifts to the right to use up the extra reactants
What happens if the concentration of a product is increased?
Equilibrium shifts to the left to remove the extra product
What happens if the pressure is increased?
The equilibrium shifts to the side with fewer moles, reducing the pressure
What does pressure affect?
Gases
What happens if pressure is decreased?
Equilibrium shifts to the side with the most moles to raise the pressure
What happens if temprature is increased?
The equilibrium shifts to the endothermic side to absorb the heat
What happens if temperature is decreased?
The equilibrium shifts to the exothermic side to replace the heat
What happens if the forward reaction is endothermic?
The reverse reaction is exothermic
How are conditions chosen in industry?
As a compromise
What are conditions chosen to produce?
A high rate and high yield
How is ethanol made?
From ethene and steam
What is the equation for ethanol production?
C2H4 + H2O –> C2H5OH
What pressure is used for ethanol production?
60-70 atm
What temperature is used for ethanol production?
300 degrees
What catalyst is used for ethanol production?
Phosphoric acid
Why is the temperature for ethanol production relatively low?
Because the forward reaction is exothermic, so lower temperatures favour it
