A mixture of 0.500 mole of carbon monoxide and 0.400 mole of bromine was placed into a rigid 1.00-L container and the system was allowed to come to equilibrium. The equilibrium concentration of COBr2 was 0.233 M. What is the value of Kc for this reaction? CO (g) + Br2 (g) COBr2 (g)

The value for the equilibrium constant Kc is 5.23

Explanation:

Step 1: Data given

Number of moles CO = 0.500 moles

Number of moles Br2 = 0.400 moles

Volume = 1.0 L

The equilibrium concentration of COBr2 was 0.233 M.

Step 2: The balanced equation

CO (g) + Br2 (g) ⇆ COBr2 (g)

Step 3: The initial concentrations

Concentration = mol / volume

[CO] = 0.500 moles / 1L = 0.500 M

[Br2] = 0.400 moles / 1L = 0.400 M

[COBr2] = 0M

Step 4: The concentration at the equilibrium

[CO] = 0.500 - X M

[Br2] = 0.400 - X M

[COBr2] = XM = 0.233 M

[CO] = 0.500 - 0.233 = 0.267 M

[Br2] = 0.400 - 0.233 = 0.167 M

[COBr2] = XM = 0.233 M

Step 5: Calculate Kc

Kc = [COBr2]/[CO][Br2]

Kc = 0.233 / (0.267*0.167)

Kc = 5.23

The value for the equilibrium constant Kc is 5.23