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Assessment objectives
By the end of this topic, the student should be
able to:
- Explain what is meant by kinetic theory of gases.
- Explain quantitatively why a gas exerts pressure
on the walls
of its container.
- Derive the expression P = 1 r <c2>
stating any assumptions made.
- Relate the mean kinetic energy of a gas to its absolute
temperature.
- Use the formula P = 1r <c2>
to deduce Avogadro's Hypothesis,
3
Boyle's law, Charles's law, Dalton's law of partial pressures
and Graham's
law of diffusion.
- Distinguish between a real and an ideal gas.
- Account for the difference between equations PV
= RT and
( P + a )(V - b) = RT
v2
- Define critical temperature Tc
of a gas.
- Draw labelled P-V diagrams to show the
behaviour of a real gas under
compression for temperatures above and below the critical
temperature.
- Distinguish between a gas and a vapour.
- Distinguish between saturated an unsaturated vapour
and define saturated
vapour pressure.(s.v.p)
- Explain the occurrence of saturated vapour pressure
using molecular theory.
- Use kinetic theory to explain the effect of volume
and temperature change
on s.v.p.
- Distinguish the behaviour of saturated vapours from
that of unsaturated ones.
- Use Dalton's law of partial pressures to solve problems
on s.v.p
- Relate variation of s.v.p to boiling point.
- Describe an experiment to measure the variation of
s.v.p of water with
temperature.
 7.6
Thermodynamics
(12 Periods)
 Work done by an
expanding gas
Internal Energy
First law of thermodynamics
DQ = DU + DW
Principle specific
heat capacities, the relation Cp-Cv
= R
Isothermal and
adiabatic changes of a gas inlcuding work done
by a gas on such a process.
Assessment objectives
By the end of this topic, the student should be
able to:
- State the component of the internal energy of a real
gas and the factors
on which they depend.
- Define an ideal gas and show that the internal energy
of an ideal gas has no
potential energy component.
- Explain the meanings of terms: isovolumetric, isobaric,
isothermal, and
adiabatic changes.
- Derive the expression W = Pdv for the work
done when a gas expands and
relate it to the area under the P-V curve.
- State the first law of thermodynamics and apply it
to isobaric processes.
- Explain why a gas has more than one specific heat
capacity.
- Define specific heat capacity of a gas at constant
pressure and constant
volume.
- Explain why the molar principle heat capacity at
constant pressure Cp
is greater than that at at constant volume Cv.
- Derive the expression Cp-Cv
= R
- Relate g = Cp/Cv to
atomicity of a gas.
- Represent isovolumetric, isobaric, isothermal, and
adiabatic processes on
a P-V sketch.
- State the conditions necessary in practice to achieve
isothermal and adiabatic
processes.
- State and use the equations relating
- Derive expressions for the work done in isothermal
and adiabatic processes.
- Solve problems involving isovolumetric, isobaric,
isothermal, and adiabatic
processes.
7.7
Transfer of Heat Energy
Thermal Conduction.
- Mechanism of thermal conduction in insulators and in
metals.
Thermal conductivity.
The relation DQ
= k A DT
Dt
Dx
Measurement of
thermal conductivity of good and bad conductors of heat.
Convection as a
consequence of change of density.
Radiation as a
form of energy.
- Blackbody radiation
- Energy distribution in the spectrum of blackbody
radiation.
- Stefan's law E = sT4.
- Wein's displacement law, lmT
= 2.9x10-3 mK.
- Surface temperature of the sun.
- Survey of the electromagnetic spectrum.
Assessment objectives:
By the end of this topic, the student should be
able to:
- Explain the mechanism of heat conduction in gases,
liquids metallic
and non-metallic solids.
- State the factors which determine the rate of heat
transfer through
a material.
- Define thermal conductivity k of a material.
- Draw a sketch graph to show the variation of temperature
with length
along a lagged and an unlagged metal bar.
- Perform and describe an experiment to determine thermal
conductivity
of a good conductor of heat like copper and a poor
conductor of heat
like glass.
- Solve problems involving conduction of heat.
- Describe and explain the process of convection.
- State properties of infra-red radiation and describe
how it can be detected.
- Define a blackbody and blackbody radiation.
- Describe how an approximate blackbody can be realised
in practice.
- Draw sketch graphs to show variation of relative
intensity with wavelength
and describe their special features.
- State and use Wein's displacement law and Stefan's
law in calculations, including
the estimation of the temperature of the sun.
- State Prevost's theory of heat exchanges and apply
it in calculations.
- Arrange the components of the electromagnetic spectrum
in order of
decreasing wavelength.
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