Gas composition over time and thermodynamic equilibrium. Gas compositions are shown in Fig. 2. Q is the quotient [(C1)(C3)]/[(C2)2], where concentrations are % vol. The horizontal line is the equilibrium constant K (K = 10) for the reaction conditions . The solid line through the data is from the equation Q(t) = 10*(1-e-αt), where Q(t) is the quotient at time t (hours), 10 is Q at infinite time, and the constant α was set to 0.0094 to fit the data.