2.3 Thermodynamics 2.3.4 Thermal Properties and Processes
Thermal expansion in solids and liquids What you can learn about ■■ Linear expansion ■■ Volume expansion of liquids ■■ Thermal capacity ■■ Lattice potential
P2310100
■■ Equilibrium spacing ■■ Grüneisen equation
Benefits ■■ With detailed experiment guide ■■ Two experiments in one
Details
Principle The volume expansion of liquids and the linear expansion of various materials is determined as a function of temperature.
Tasks 1. To determine the volume expansion of ethyl acetate (C4H8O2), methylated spirit, olive oil, glycerol and water as a function of temperature, using the pycnometer. 2. To determine the linear expansion of brass, iron, copper, aluminium, duran glass and quartz glass as a function of temperature using a dilatometer. 3. To investigate the relationship between change in length and overall length in the case of aluminium.
Vapour pressure of water at high temperature
P2340100
What you can learn about ■■ Boiling point ■■ Heat of vaporisation ■■ Clausius-Clapeyron equation ■■ Van‘t Hoff law ■■ Carnot cycle
Benefits ■■ No open flame in the setup - Reduction of thermal hazard ■■ No gas burner required - Easy to operate and no consumption of consumables ■■ Compact, easily transportable setup
Details
Principle The high-pressure steam apparatus makes it possible to measure steam pressure in a temperature range of 100-250 °C. This allows for investigations to be performed on real gases and vapours. Typical equilibrium states between gas and liquid phases can be setup. For this purpose, water is heated in a closed pressure chamber at constant volume. The heat of vaporisation is determined at various temperatures from the measurement of vapour pressure as a function of temperature.
PHYWE SYSTEME GmbH & Co.KG —
Tasks 1. Measure the vapour pressure of water as a function of temperature. 2. Calculate the heat of vaporisation at various temperatures from the values measured. 3. Determine boiling point at normal pressure by extrapolation.
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