Principle

When two miscible liquids are mixed, a positive or negative heat effect occurs, which is caused by the interactions between the molecules. This heat effect is dependent on the mixing ratio. The integral mixing enthalpy and the differential molar mixing enthalpy can be determined by calorimetric measurements of the heat of reaction.

Benefits

• Part of a system solution - Easily expandable for further experiments
• Calorimeters with particularly high capacitance
• Simplified implementation: all pre-settings already prepared

Tasks

1. Measure the integral mixing enthalpy of seven different water-acetone mixtures.
2. Plot the molar integral mixing enthalpy versus the quantity of substance (mole fraction) and determine the molar mixing enthalpy.
3. Discuss the results on the basis of the interactions in the mixture.
   

Learning objectives

• Differential molar mixing enthalpy
• Real and ideal behaviour
• Integral molar mixing enthalpy
• Fundamental principles of thermodynamics
• Calorimetry

Necessary accessories

• Precision balance 6200g/0.01g