EQUILIBRIUM SYSTEMS Flashcards
What is a reversible reaction?
A reversible reaction is a reaction in which the conversion of reactants to products is able to reverse and the products can convert back to reactants
What is the point of equilibrium is an equilibrium system?
Equilibrium is reached when the rate of the forward reaction = the rate of the reverse reaction
How do you interpret an equilibrium curve?
The reactant will start with a high concentration and the product will start with a concentration of 0
the reactant decreases quickly at first and then levels off as it approaches an equilibrium state, the product increases quickly at first, then levels off as it approaches an equilibrium state.
What is Le Chatelier’s principle?
When a system at equilibrium is subject to stress/changing conditions, the equilibrium position shifts to compensate for the effects of that change
Use examples to define Le Chatelier’s principle
when you add more reactant to an equilibrium system it shifts the reaction in a forwards direction, when you add more product to an equilibrium system it shifts to make more of the reactants and pushes the reaction in a reverse reaction.
What happens if you heat or cool a system at equilibrium?
If you add heat to the system at eq, reverse reaction speeds up until new eq is reached
If you cool system at eq, forward reaction speeds up until new eq is reached
Heat can be included as a product for an exothermic reaction
Heat can be included as a reactant for an endothermic reaction
Describe the relation between equilibrium systems and pressure changes
Increase in pressure = shift to side with fewest moles of gas
Decrease in pressure = shift to side with most moles of gas
Increase in volume = side with most moles of gas
Decrease in volume = side with fewest moles of gas
What is the equilibrium constant expression?
Keq = [C]^c [D]^d/ [A]^a [B]^b
It is specific to a reaction at a particular temperature
If the ratio of products to reactants = Keq, the system is at equilibrium
Keq more than 1 = product favoured
Keq less than 1 = reactant favoured
Keq = Kc when concentrations are in mol.L^-1
What are the types of equilibrium?
Homogenous equilibrium: reactants and products are in the same state of matter
Heterogenous equilibrium: Reactants and products are in different states of matter
What is the reaction quotient, Q?
When reactants and products in a reaction are not at eq, and we know their concentrations at a specific time, we calculate the reaction quotient Q
Q = eq expression => ABCD are concetrations of reactions and products as the reaction proceeds towards equilibrium at eq Q = Keq
Relative magnitude Direction of reaction
Q < K =>
Q = K =
Q > K <=
How does a catalyst alter equilibrium reactions?
A catalyst is a substance that increases the speed of a reaction. Overall, a catalyst is not a reactant and is not used up, but it still affects how fast a reaction proceeds. However, a catalyst does not affect the extent or position of a reaction at equilibrium. It helps a reaction achieve equilibrium faster
