Chemistry

Membrane filter method

Phosphating of aluminium

Water quality - contamination with heavy metals

Principle

Heavy-metal ions may be carried into surface or ground water from mining fields or via the waste water of galvanicor similar production sites. They block the effect of enzymes so that the processes in the metabolism of the organisms that are controlle ...

Filtration, magnetic separation

Principle

This experiment to be performed by students themselves, demonstrates how a mixture of salt and sand can be separated into its components. This involves adding some water to a mixture of solid salt and solid sand to make a suspension which is then poured through a fi ...

Distillation

Principle

In the experiment introduced here, a mixture of water and methylated spirits made up by students themselves is to be separated into its components. The alcohol contained in the mixture will be distilled and collected in a conical flask. The simple distillation ...

Brownian molecular motion

Principle

Molecules in liquids are relatively free to move. They can transfer their energy to neighbouring molecules, causing them to oscillate. This allows the motion of the molecules to be observed indirectly simply using a microscope.

Quantitative analysis of oxides

Carbon dioxide, preparation and properties

Principle

Carbon dioxide can be obtained very simply from carbonates (e.g. marble) by dripping acid onto them. The properties of the gas obtained in this way can then be investigated with little difficulty. The student experiment described here demonstrates, among other th ...

Osmosis: a "chemical garden"

Principle

One impressive example of osmotic processes is the "chemical garden". Metal salts dropped into a solution of sodium silicate react with the silicate immediately, forming non-soluble silicate shells, which stop the reaction from proceeding further. However the shells ...

Test confirming the migration of ions by means of indicator paper

Principle

Strips of indicator paper soaked in potassium nitrate solution are spanned between two copper electrodes inside a ribbed trough. A drop of hydrochloric acid or sodium hydroxide is dripped onto the middle of these strips. When a voltage is applied, it can b ...

Preparation of methane

Principle

With the help of the simple experiment set-up shown here, methane can be made from aluminium carbide and water. If the methane gas is collected in a test tube, it is then possible to investigate its properties.

Melting and freezing curve of sodium thiosulphate

Principle

How does a temperature curve express the change of state of a substance that occurs when it is heated or cooled?

Tasks

Heat sodium thiosulphate until it melts and let it cool down again. Measure the behaviour of the ...

Melting point determination

Boiling point determination