#### Enthalpy of Mixing and Deviation from Raoult's Law: Interactive Simulation

This simulation runs in your browser. Try to predict the behavior when a parameter changes before using a slider to change that parameter. A screencast below explains how to use this simulation.

##### Simulation: Partial Molar Enthalpy

The molar enthalpy of a binary mixture of A and B is plotted as a function of the mole fraction of component A. The end points of the molar enthalpy are the pure-component enthalpies (H_{A} and H_{B}). The partial molar enthalpies \(\overline{H}_A\) and \(\overline{H}_B\), are obtained by drawing a tangent line at the black point (indicating the mole fraction of the solution). The intersections of this tangent with the y axis at x_{A} = 0 and x_{A} = 1 correspond to \(\overline{H}_B\) and \(\overline{H}_A\), respectively. You can change the mole fraction of A in the mixture with the slider. For an ideal solution (non-ideal parameter = 0), the enthalpy of the mixture is a linear function of the molar enthalpies of the pure components. For a non-ideal solution, you can vary a parameter that represents the deviation from ideality.

**Try to answer this question before determining the answer with the simulation**. We suggest that you write down the reasons for your answers.

If mixing is exothermic, is the partial molar enthalpy of component A greater than or less than the pure-component enthalpy?