Chemical Equilibrium Flashcards
At equilibrium are the concentrations equal?
No, they are constant, not necessary equal
What is equilibrium?
When the rate of the forward reaction equals the rate of the reverse reaction.
What is Keq?
Equilibrium constant.
Concentration of the products over concentration of the reactants
What happens when Keq is greater than 1?
System favours the products
What happens when Keq is less than 1?
System favours reactants
What happens when Keq equals 1?
Concentration of products equals concentration of reactants
What is the mass action expression?
The concentration of the products raised to their coefficients over the concentration of the reactants raised to their coefficients
What can enter the mass action expression?
Only aqueous and gas forms
What is the reaction quotient?
Represented by Qc. Calculated by substituting the initial concentrations of the reactants and products into the equilibrium constant expression.
What happens when Qc is less than Kc?
Reaction proceeds left to right to establish equilibrium
What happens when Qc equals Kc?
System is at equilibrium
What happens when Qc is greater than Kc?
Reaction proceeds right to left in order to establish equilibrium
How do you calculate Keq?
Use the mass action expression. You may have to rearrange, set up an ice table, use variables, factor, use the quadratic formula and or the 500 rule
How do you set up an ice table?
Initial concentration
Change in concentration
Equilibrium concentration
What is the 500 rule check?
Take the initial concentration of reactant and divide by Keq. If this number is greater than 500, you can eliminate x in the denominator.