A student measures the pressure exerted by \(1.00\text{ mol}\) of \(\text{CH}_4\text{(g)}\) and \(1.00\text{ mol}\) of \(\text{NH}_3\text{(g)}\) in separate, identical \(1.00\text{ L}\) rigid containers at \(250\text{ K}\). Under these conditions, the measured pressure for each gas is less than the pressure predicted by the ideal gas law, and the measured pressure of \(\text{NH}_3\text{(g)}\) is significantly lower than that of \(\text{CH}_4\text{(g)}\). Which of the following statements best justifies the observed difference in pressure between the two gases?