Question

The equilibrium constant, KcKc, is calculated using molar concentrations. For gaseous reactions another form of the equilibrium constant, KpKp, is calculated from partial pressures instead of concentrations. These two equilibrium constants are related by the equation

Kp=Kc(RT)ΔnKp=Kc(RT)Δn

where R=0.08206 L⋅atm/(K⋅mol)R=0.08206 L⋅atm/(K⋅mol), TT is the absolute temperature, and ΔnΔn is the change in the number of moles of gas (sum moles products - sum moles reactants). For example, consider the reaction

N2(g)+3H2(g)⇌2NH3(g)N2(g)+3H2(g)⇌2NH3(g)

for which Δn=2−(1+3)=−2Δn=2−(1+3)=−2.

A

For the reaction

3A(g)+3B(g)⇌C(g)3A(g)+3B(g)⇌C(g)

KcKc = 71.0 at a temperature of 391 ∘C∘C .

Calculate the value of KpKp.

Express your answer numerically.

B

For the reaction

X(g)+2Y(g)⇌3Z(g)X(g)+2Y(g)⇌3Z(g)

KpKp = 1.33×10⁻² at a temperature of 25 ∘C∘C .

Calculate the value of KcKc .

Express your answer numerically.