property value in pure state and in solution differs. for example if we take the molar volume of pure water is 18.069 ml/mol but if 1 mol of water is added to 1 mol of ethanol, the partial molar volume of water is about 16.9 ml/mol. if we add 1017 ml of methanol and 1053 ml of water, we expect to get 2070 ml solution, but we get 2000 ml solution. this shows that the volume of solution decreases or volume change of mixing is -70 ml.
Like volume the different properties like enthalpy, entropy, Gibbs free energy also differs in the pure state and in solution. the solution property like U, H S, G, V can be calculated form partial properties by multiplying with the mole fraction or number of moles and summing it.
the difference between the solution property and sum of the partial molar enthalpy is called the change of property of mixing. i.e. M-∑yiMi, where Mi is the molar property in its pure state.
the enthalpy change of mixing of ideal gases is zero, but the entropy change of mixing of ideal gases is greater than zero, as it is an irreversible process which has entropy change positive.
Like volume the different properties like enthalpy, entropy, Gibbs free energy also differs in the pure state and in solution. the solution property like U, H S, G, V can be calculated form partial properties by multiplying with the mole fraction or number of moles and summing it.
the difference between the solution property and sum of the partial molar enthalpy is called the change of property of mixing. i.e. M-∑yiMi, where Mi is the molar property in its pure state.
the enthalpy change of mixing of ideal gases is zero, but the entropy change of mixing of ideal gases is greater than zero, as it is an irreversible process which has entropy change positive.
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