Page 99 - CatalogNEP-PS

LEARNING OUTCOMES:

By the end of the course, the students will be able to:
 Derive mathematical expressions for different properties of gas and liquid and understand
their physical significance.
 Apply the concepts of gas equations and liquids while studying other chemistry courses
and everyday life.
 Handle stalagmometer and Ostwald viscometer properly.
 Determine the density of aqueous solutions.

THEORY (45 Hours)

UNIT – I (24 Hours)
Gaseous state
Kinetic Theory of gases- postulates and derivation of kinetic gas equation, Maxwell distribution
of molecular velocities and its use in evaluating average, root mean square and most probable
velocities and average kinetic energy. Definition, expression, applications and temperature and
pressure dependence of each one of the following properties of ideal gases: Collision frequency,
Collision diameter, Mean free path. Coefficient of viscosity, definition, units and origin of
viscosity of gases, relation between mean free path and coefficient of viscosity, temperature and
pressure dependence of viscosity of a gas, calculation of molecular diameter from viscosity
Barometric distribution law, its derivation and applications, alternative forms of barometric
distribution law in terms of density and number of molecules per unit volume, effect of height,
temperature and molecular mass of the gas on barometric distribution
Behaviour of real gases- Compressibility factor, Z, Variation of compressibility factor with
pressure at constant temperature (plot of Z vs P) for different gases ( H 2, CO 2, CH 4 and NH 3),
Cause of deviations from ideal gas behaviour and explanation of the observed behaviour of real
gases in the light of molecular interactions
van der Waals equation of state,Limitations of ideal gas equation of state and its modifications in
the form of derivation of van der Waal equation, Physical significance of van der Waals constants,
application of van der Waal equation to explain the observed behaviour of real gases.
Isotherms of real gases- Critical state, relation between critical constants and van der Waals
constants, correlation of critical temperature of gases with intermolecular forces of attraction,
Continuity of states, Limitations of van der Waals equation, Reduced equation of state and law of
corresponding states (statement only).
Virial equation of state-Physical significance of second and third virial coefficients, van der
Waals equation expressed in virial form, Relations between virial coefficients and van der Waals
constants
UNIT – II (6 Hours)

Liquid state
Nature of liquid state, qualitative treatment of the structure of the liquid state
Physical properties of liquids-vapour pressure, its origin and definition, Vapour pressure of liquids
and intermolecular forces, and boiling point
Surface tension, its origin and definition, Capillary action in relation to cohesive and adhesive
forces, determination of surface tension by (i) using stalagmometer (drop number and drop mass
method both) and (ii) capillary rise method, Effects of addition of sodium chloride, ethanol and
detergent on the surface tension of water and its interpretation in terms of molecular interactions,
Role of surface tension in the cleansing action of detergents
Coefficient of viscosity and its origin in liquids, Interpretation of viscosity data of pure liquids
(water, ethanol, ether and glycerol) in the light of molecular interactions, Effects of addition of
sodium chloride, ethanol and polymer on the viscosity of water, relative viscosity, specific

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