Gaseous hydrogen bromide decomposes at elevated temperatures according to the following equation:
2 HBr(g) ⇌ H₂(g) + Br₂(g) .
At a certain temperature a 2.00 L flask is initially filled only with 0.600 mol of HBr.What is the value of K_c at that temperature if the flask contains 0.104 mol of H₂ at equilibrium?

Question

Quizplus · Accepted Answer

The equilibrium constant expression for this reaction is:K_c = [H₂][Br₂]/[HBr]²At equilibrium, the concentrations of the gases are:[H₂] = 0.104 mol/2.00 L = 0.0520 M[Br₂] = 0.104 mol/2.00 L = 0.0520 M[HBr] = (0.600 mol - 2(0.104 mol))/2.00 L = 0.196 MSubstituting these values into the equilibrium constant expression, we get:K_c = (0.0520 M)(0.0520 M)/(0.196 M)² = 7.04 × 10^-2

Gaseous Hydrogen Bromide Decomposes at Elevated Temperatures According to the Following