Heat is added to a gas in a glass vessel by an electric heater which is switched on briefly. The temperature increase results in a pressure increase, which is measured with a manometer. Under isobaric conditions a temperature increase results in a volume dilatation, which can be read from a gas syringe. The molar heat capacities Cv and Cp are calculated from the pressure or volume change.

Benefits

• Determination of cp and cv
• For both demonstration and student experiments
• Suitable for many different gases

Tasks

Determine the molar heat capacities of air at constant volume Cv and at constant pressure Cp.

Learning objectives

• Equation of state for ideal gases
• First law of thermodynamics
• Universal gas constant
• Degree of freedom
• Mole volumes
• Isobars
• Isotherms
• Isochors and adiabatic changes of state

Heating coil for student calorimeter (04404.88).

Equipment and technical data

• Heating coil on two 90 mm rods,
• with two 4 mm sockets,
• distance: 19 mm.

The volume expansion of liquids and the linear expansion of various materials is determined as a function of temperature.

Benefits

• With detailed experiment guide
• Two experiments in one

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.

What you can learn about

• Linear expansion
• Volume expansion of liquids
• Thermal capacity
• Lattice potential
• Equilibrium spacing
• Grüneisen equation

Due to internal friction among their particles, liquids and gases have different viscosities. The viscosity, a function of the substance’s structure and its temperature, can be experimentally determined, for example, by measuring the rate of fall of a ball in a tube filled with the liquid to be investigated.

Benefits

• Viscosity measurement for two fluids and any mix ratio
• Viscosity measurement for different temperatures possible
• Angle of falling ball viscometer can be changed
• Interdisciplinary use also in applied sciences or physical chemistry

Tasks

Measure the viscosity

1. of methanol-water mixtures of various composition at a constant temperature,
2. of water as a function of temperature and
3. of methanol as a function of temperature.

From the temperature dependence of the viscosity, calculate the energy barriers for the displace ability of water and methanol.

Learning objectives

• Liquid
• Newtonian liquid
• Stokes law
• Fluidity
• Dynamic and kinematic viscosity
• Viscosity measurements

The viscosity of liquids can be determined with a rotation viscometer, in which a motor with variable rotation speed drives a cylinder immersed in the liquid to be investigated with a spiral spring. The viscosity of the liquid generates a moment of rotation at the cylinder which can be measured with the aid of the torsion of the spiral spring and read on a scale.

Benefits

• Classic experiment to determine the viscosity of a huge variety of fluids
• Watch all results directly on the built-in multilanguage display
• Use several spindles that come with a storage rack
• Wearless torque measuring system with high accuracy
• Digital speed control
• Interdisciplinary use also in applied sciences or physical chemistry

Tasks

1. Determine the gradient of the rotational velocity as a function of the torsional shearing stress for two Newtonian liquids (glycerine, liquid paraffin).
2. Investigate the temperature dependence of the viscosity of Castor oil and glycerine.
3. Determine the flow curve for a non Newtonian liquid (chocolate).

Learning objectives

• Shear stress
• Velocity gradient
• Internal friction
• Viscosity
• Plasticity

• Gas law of Boyle-Mariotte
• Gas law of Gay-Lussac
• Gas law of Amonton (Charles)
• Determination of molar masses according to the vapor density method

Benefits
This set allows to execute the measurements in a didactically clear and easily understandable way:

• clear set-up
• easy to understand
• fast execution
• short preparation time
• completely mercury-free

Equipment and Technical Data
It will be delivered complete with tripod material and all necessary small hardware items:

• Glass jacket
• Gas syringe
• Heater
• Tripod material
• Small hardware items
• CD with literature

Not included are measuring instruments such as thermometers or manometers.

Accessories
Data acquisition set with Cobra3 Basic unit for recording the measured data by means of a PC.