15.1 Equilibrium and Equilibrium Constants
The rate of the forward reaction equals the rate of the reverse reaction.
Concentrations of reactants and products are not changing.
Equilibrium Constants (Law of Mass Action)
-Equals the ratio of the concentrations of products to the concentrations of reactants at equilibrium raised to the power of their coefficients.
-Only aqueous and gaseous species are included.
-Equilibrium constants are CONSTANTS; the value will only change with a change in temperature.
-An equilibrium constant also equals the ratio of the forward and reverse rate constants.
|K >> 1||Favors Products|
|K << 1||Favors Reactants|
|10-3 < K < 103||Reactants and productsboth present at equilibrium|
2C(s) + O2(g) ⇌ 2CO(g)
Write the equilibrium constant expression (Kc and Kp) for the reaction above.
Kp vs Kc
Kp = Kc (RT)Δn Δn = change in moles gas R = 0.0821 L•atm/mol•K
If for 2C(s) + O2(g) ⇌ 2CO(g) Kc = 1200 at 400K, then what is the value of Kp?
2SO2(g) + O2(g) ⇌ 2SO3(g) Kc = 4.0
Based on the reaction above, what are the equilibrium constants for the following reactions?
2SO3(g) ⇌ 2SO2(g) + O2(g)
SO2(g) + ½O2(g) ⇌ SO3(g)
SO3(g) ⇌ SO2(g) + ½O2(g)