10. The van der Waals equation of state is na P + V? (V nb) = nRT v - When the temperature of a given gas is equal to its critical temperature, the gas has a state at which the pressure as a function of V at constant T and n exhibits an inflection point at which dP V = 0 and d-P/dV2 = 0. This inflection point corresponds to the critical point of the gas. Write P as a function of TV and n and write expressions for dP V and dp/dV4 creating T and n as constants. Set these two expressions equal to zero and solve the simultaneous equations to find an expression for the pressure at the critical point