The Peng-Robinson equation of state is used to compute the correction factor due to gas-phase nonideality, , as a result of the high pressure applied in the synthesis of ammonia (. In addition, the extent of reaction is computed. The Demonstration plots these two quantities versus pressure for temperatures ranging from 1000°R to 1500°R.

The extent of reaction is high and approaches one at very high pressure and low temperature, as expected from LeChatelier's rule. is close to one at low pressure and is considerably smaller than one for high pressure, which indicates that this correction factor must be taken into account at high pressure.

The correction factor due to gas-phase nonideality is given by , where , , and are the fugacity coefficients of the species involved; they are calculated using the Peng-Robinson equation of state.