Thermochemistry, Calorimetry

Enthalpy and entropy as driving forces of chemical reactions

Thermal decomposition of water - example of an endothermicprocess

Neutralisation - neutralisation enthalpy

Heat of solution - enthalpy of solution

Determination of the enthalpy of vaporisation of liquids (with the Cobra3 Basic-Unit)

Principle

The vaporization of a liquid occurs with heat absorption. To determine the enthalpy of vaporization, a known mass of the liquid which is to be investigated is vaporized in a special vaporization vessel in a current of air. The quantity of heat absorbed, which corres ...

Determination of the mixing enthalpy of binary fluid mixtu-res (with the Cobra3 Basic-Unit)

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 mixin ...

Determination of the hydration enthalpy of an electrolyte (solution enthalpy) (with the Cobra3 Basic-Unit)

Principle

When a solid electrolyte dissolves in water, a positive or negative heat effect occurs as a result of the destruction of the crystal lattice and the formation of hydrated ions. The enthalpy of hydration of copper sulphate can be calculated from the different heats o ...

Determination of the enthalpy of neutralisation (with the Cobra3 Basic-Unit)

Principle

When a strong acid is neutralised with a strong base in dilute solution, the same amount of heat is always released. If the reaction takes place under isobaric conditions, this heat is known as the enthalpy of neutralisation. The chemical reaction which generates th ...

Determination of the melting enthalpy of a pure substance(with Cobra3 BASIC UNIT)

Principle

When a solid melts, energy is required for the destruction of the crystal lattice. A substance whose melting point lies slightly below room temperature is first cooled until it solidifies and then melted in a calorimeter. The melting enthalpy is calcu ...

Determination of the enthalpy of combustion with a calorimetric bomb

Principle

The  bomb calorimeter is used to completely burn substances in an excess of oxygen.The heat of combustion released is absorbed by the calorimetric vessel in which the bomb is immersed, and results in a temperature increase ΔT. The heat capacity of th ...

Determination of the heat of formation of water

Principle

Standard molar enthalpies of formation Δ_BH^Φ are important compiled thermodynamics tabulation quantities for calculating standard enthalpies of reaction for any arbitrary reaction. They are defined as the heat of reaction occurring in ...

Determination of the heat of formation for CO2 and CO (Hess' law)

Principle

The standard molar enthalpies of formation Δ_BH^Φ are important compiled thermodynamic tabulation quantities for calculating standard enthalpies of reaction for any arbitrary reaction. They are defined as the heat of reaction occurring ...

Determination of the heating value of fuel oil and of the calorific value of olive oil

Principle

The heat of reaction generated during the complete combustion of 1000g of solid or liquid fuel is known as the calorific value H. In the case of complete combustion of nutritional fats, the gross calorific value can also be determined. In ord ...

Vapour pressure of mixtures of ideal liquids

Principle:

According to Raoult's law, the vapour pressures of ideal solutions is the sum of the partial pressures of the individual components. Mixtures of benzene and toluene display an almost ideal behaviour.

Tasks:

Solubility diagram of two partially miscible liquids

Principle:

A number of different mixtures of phenol and water are prepared and heated until complete miscibility is achieved. As the mixtures cool, two-phase systems form at certain temperatures which are recognisable by the appearance of turbdidity. Plotting separation temp ...