Equilibrium Flashcards
What is the Reaction Quotient (Q)
This is the ratio of the concentration or pressure of the product raised to the power equal to its mole, to the concentration/pressure of the reactant raised by its mole before the reaction reaches equilibrium.
What is the main difference between Equilibrium Constant (K) and Reaction Quotient (Q)?
K describes a reaction that is at equilibrium while Q describes a reaction that is not at equilibrium.
What happens if Q > K ?
(Alligator bites in the direction of shift as long as Q is written first)
Reaction shifts to the left; there are less reactants before equilibrium and so for balance the reaction shifts to form more reactants.
What happens when Q < K?
(Alligator bites in the direction of shift as long as Q is written first)
Reaction shifts to the right; there are less products before Equilibrium and so for balance the reaction shifts to form more products.
What happens when Q = K ?
The system is already at equilibrium.
State the rules for calculating the equilibrium constant for derived chemical reactions.
- The equilibrium constant of the backward reaction is the multiplicative inverse of that of the forward reaction.
- If an equation is derived my multiplying a given equation by ‘m’ with equilibrium constant ‘x’, then the ita equilibrium constant is x^m
- If an equation is derived by adding two (A + B) or more given equations then the equilibrium constant = multiplication of the two equilibria constants (A × B)
State Le Chatelier’s Principle.
It states that if a constraint is introduced to a system in equilibrium by the change in equilibrium conditions such as temperature, then the system adjusts to cancel out the change.
What is the effect of increase in temperature in an endothermic reaction?
The forward reaction is favoured.
What is the effect of increase in temperature in an exothermic reaction?
The backward reaction is favoured.
What is the effect of increasing pressure in an equilibrium system?
It favours the side with lower moles of gases.
P ∝ 1/n (n = number of moles)
What is the effect of decreasing pressure in an equilibrium system?
It favours the side with higher moles of gases.
P ∝ 1/n (n = number of moles
What is the effect of change in concentration?
Increase in concentration of a species in one side favours the opposite side; decrease in conc of species in one side favours the same side.
What is the effect of catalyst on an equilibrium system?
There is no effect; catalyst favours forward and backward reaction at same rate, resulting in a net effect of zero.
What is heterogeneous equilibria?
This is a type of equilibrium reaction where the reacting species are of different physical states.
What is homogenous equilibria?
This is a type of equilibrium reaction where the reacting species are of the same physical states.
