Anomalies in the thermodynamic properties of mixtures near the liquid-vapor critical point

The behavior of the specific heat at constant volume and the derivative (∂P/∂T)_{ρ, x} has been studied experimentally near the liquid-vapor critical point of the methane-propane-pentane mixture. It has been shown that the derivative ∂P/∂T)_{ρ, x} for mixtures, in contrast to one-component systems, has a characteristic anomaly directly associated with an anomaly in the specific heat at constant volume. It is impossible to distinguish between the infinite increase in the specific heat or finite peak when processing of the experimental data only for the heat capacity. However, according to the joint analysis of the experimental data for both indicated quantities, both the specific heat of the mixture and the derivative ∂P/∂T)_{ρ, x} are singular finite quantities.