Determination of the enthalpy of vaporisation of liquids with CobraSMARTsense

Principle

The vaporisation of a liquid occurs with heat absorption. To determine the enthalpy of vaporisation, a known mass of the liquid which is to be investigated is vaporised in a special vaporisation vessel in a current of air. The quantity of heat absorbed, which corresponds to the enthalpy of vaporisation, can be calorimetrically determined.

Benefits

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

Tasks

1. Determine the molar enthalpy of vaporisation of diethyl ether and methanol.
2. Calculate the molar entropies of vaporisation and discuss the results under consideration of Trouton's rule.

Learning objectives

• Enthalpy of vaporisation
• Enthalpy of condensation
• Enthalpy of sublimation
• Vapour pressure
• Entropy of vaporisation
• Clausius-Clapeyron equation
• Trouton's rule
• Law of thermodynamics
• Calorimetry

Necessary accessories

• Precision balance 620g/0.001g
• Precision balance 6200g/0.01g

Software included. Computer not provided.