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9.4.5 Draw the graph of the dependence σ = f (С )
ker surfact surfact
(С  concentration of surfactant, % mass.).
surfact

9.5 Checking questions

9.5.1 Give the definition of surface tension.
9.5.2 What are dimensions (units of measurement) of the

surface tension?
9.5.3 What equipment, devices and materials are used in the

laboratory experiment?
9.5.4 What devices are used to determine the surface tension?
9.5.5 Enumerate the methods to measure the surface tension

of liquids (water solutions of surface-active agents (surfactants)).
9.5.6 The structure of the stalagmometer.
9.5.7 Give the definition of the surface tension in general.

9.5.8 The principle of determining the surface tension of
surfactant solutions by means of stalagmometer.
9.5.9 What is the main part of stalagmometer?

9.5.10 How do surfactants influence the surface tension of water?
9.5.11 Explain the dependence of the surface tension of liquid on
the temperature.
9.5.12 What is the unit of measurement of the capillary constant?

9.5.13 Write down the equation which describes the dependence
of the surface tension on the temperature. Give identification of all

symbols in the equation and all units of measurement.
9.5.14 Write down the equation for determining the surface
tension on the border of two liquids (kerosene–surfactant). Give

identification of all symbols in the equation and all units of

measurement.

9.6 References
/1,3,4,10/

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