Item no.: P2545001 Principle Various alloyed materials are subjected to polychromatic X-rays. The energy of the resulting fluorescence radiation is analysed with the aid of a semiconductor detector and a multichannel analyser. The energy of the corresponding characteristic X-ray fluorescence lines is determined. In order to determine the concentration of the alloy constituents, the intensity
Item no.: P3031760 Principle Chromatographic procedures allow a separation of substance mixtures with the aid of a stationary separation phase and a mobile phase. In gas chromatography the mobile phase is a gas. The mobile phase, to which the mixture to be separated is added, transports the substance mixture through the separation column at a
Item no.: P3111000 Principle In 1811, Avogadro stated his hypothesis that under the same conditions of pressure and temperature, equal volumes of all gases contain equal numbers of components (molecules, atoms). He derived this from the uniformity of the behaviour of (ideal) gases on increases in temperature and pressure (see the Gas Laws) and the
Item no.: P3030501 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 turbidity. Plotting separation temperatures against compositions of the mixtures gives the separation curve. Tasks Plot the
Item no.: P3020861 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 this heat is the reaction of protons and
Item no.: P3010501 Principle The molar mass of a liquid is to be determined by evaporating a liquid at constant temperature and pressure, and measuring the volume of vapour formed using a calibrated gas syringe. Tasks Determine the molar masses of diethyl ether and methanol. Discuss the results in terms of the real and ideal
Item no.: P3030960 Principle Carboxylic acids are potential electrolytes which exist in a weakly dissociated condition in aqueous solutions. The location of the dissociation equilibrium is quantitatively described by the Ka or pKa value which can be determined with potentiometric measurements. Tasks Measure the alteration of the pH value during a titration of approximately 0.1
Item no.: P3121060 Principle Potassium permanganate solutions which are used as oxidizing measuring solutions in redox titrations can in most cases be replaced by Ce(IV) solutions. These offer the advantages that they do not change on storage and that the course of the redox titration can be very conveniently followed by measuring the electrochemical potential.