Electrochemistry

Determination of the isoelectric point of an amino acid(glycine) with the Basic-Unit

Automatic titration of household vinegar, complete set (interface version Cobra3 Chem-Unit)

Electrolysis

Principle

The characteristic curve of current against voltage of an electrolytic bath containing copper sulphate solution and having copper electrodes is measured. Visible changes in the electrodes and the bath are observed.

Tasks

Charge transport in solids

Principle

Measuring the temperature dependence of the resistivity of solids provides information on the mechanism of conduction and charge transport in solids.

Tasks

Determine the temperature coefficient of iron wire, copper ...

Charge transport in liquids (Drying oven required!) (with the Cobra3 Basic-Unit)

Principle

A potential difference between two electrodes in a liquid causes the flow of a current in the liquid. This current depends on the potential drop across the liquid and its conductivity. The measurement of the conductivity of electolyte solutions yields knowledge abou ...

Charge transport in liquids (Drying oven required!) (withthe Cobra3 Chem-Unit)

Principle:

A potential difference between two electrodes in a liquid causes the flow of a current in the liquid. This current depends on the potential drop across the liquid and its conductivity. The measurement of the conductivity of electolyte solutions yield ...

Ion migration velocity

Principle

The movement of ions is responsible for current flow in solutions of electrolytes. The migration of coloured ions can be easily observed by the migration of the colour front in an electric field.

Tasks

Demons ...

Transference numbers

Principle

Cations and anions contribute to charge transport in electrolytic processes in accordance with their different mobilities in an electric field. Hittorf transport numbers characterise the fraction of the total charge transported by a particular ion during electrolysi ...

Temperature dependence of conductivity (with the Cobra3 Basic-Unit)

Principle

The electrical conductivity of an electrolytic solution is dependent not only upon the type and concentration of the electrolytes, but also other state values. Thus, an increase in conductivity is generally observed with an increase in temperature. This is fundament ...

Temperature dependence of conductivity (with the Cobra3 Chem-Unit)

Principle

The electrical conductivity of an electrolytic solution is dependent not only upon the type and concentration of the electrolytes, but also other state values. Thus, an increase in conductivity is generally observed with an increase in temperature. This is fundament ...

Conductivity of strong and weak electrolytes (with the Cobra3 Basic-Unit)

Principle

It is possible to differentiate between strong and weak electrolytes by measuring their electrical conductance. Strong electrolytes follow Kohlrausch's law, whereas weak electrolytes are described by Ostwald's dilution law. The examination of the concentration depen ...

Conductivity of strong and weak electrolytes (with the Cobra3 Chem-Unit)

Principle

It is possible to differentiate between strong and weak electrolytes by measuring their electrical conductance. Strong electrolytes follow Kohlrausch's law, whereas weak electrolytes are described by Ostwald's dilution law. The examination of the concentration depen ...

Conductivity titration (with the Cobra3 Chem-Unit)

Principle

The electric conductivity of aqueous electrolyte solutions is determined by the type and number of charge carriers at constant temperature. Characteristic changes in conductivity are connected with changes in the ionic composition of reacting systems. These c ...

Determination of the activity coefficient by a conductivity measurement

Principle

The equivalent conductivity of strong electrolytes depends on their concentration. The quotient of the equivalent conductivity at a certain concentration and the equivalent conductivity at infinite dilution is called the conductivity coefficient, which is tthe resu ...

The Nernst equation

Principle

The Nernst equation expresses how the electrical potential of an electrode in contact with a solution of ions depends upon the concentrations (more accurately, activities) of those ions. The equation may be experimentally verified using an electrochemical cell forme ...