```Specific Heat Capacity                                 Latent Heat or Phase Transition
 It is the heat energy per mass unit required
   It is the amount of heat per unit mass                 for a phase change (i.e. solid, liquid, or
required to raise the temperature by one               gas) to occur.
degree Celsius.
 Its SI units is J/kg.
   The units for the specific heat capacity are
 The formula for latent heat is:
J
[c]                                               Q=m*L
kg.K
 This equation relates the heat Q that must
Substance        C (J/g °C)                   be added or removed for an object of mass
Air               1.01                            m to change phases. The object"s
Aluminum          0.902
individual latent heat is noted by L.
Gold              0.129
Iron              0.450                        The values of latent heat are variable
NaCl              0.864                           depending on the nature of the phase
Ice               2.03                            change taking place:
Water             4.18
 The latent heat of fusion is the change
from liquid to solid.
Thermodynamics                                          The latent heat of vaporization is from
liquid to gas.
It deals with heat and temperature and their            The latent heat of sublimation is the
relation to energy and work.                               change from solid to gas.
Thermal Expansion
The four laws of thermodynamics are:
 It occurs when an object expands and
   Zeroth law of thermodynamics – If two                  becomes larger due to a change in the
thermodynamic systems are each in                      object"s temperature.
thermal equilibrium with a third, then they         When a substance is heated, the particle
are in thermal equilibrium with each other.            within it start to move about causing them
   First law of thermodynamics – Energy                   to increase in motion, thus resulting in the
can neither be created nor destroyed. It can           particle creating more space between them
only change forms. In any process, the                 hence the substance increases in size.
total energy of the universe remains the           Humidity
same. For a thermodynamic cycle the net             It is the quantity representing the amount
heat supplied to the system equals the net             of water vapour in the atmosphere or in a
work done by the system.                               gas.
   Second law of thermodynamics – The                  Water vapor is the gaseous state of water
entropy of an isolated system not in                   and is invisible.
equilibrium will tend to increase over              Humidity is measured by hygrometer.
time, approaching a maximum value at                Absolute humidity : It is the mass of
equilibrium.                                           water vapor divided by the mass of dry air
   Third law of thermodynamics – As the                   in a volume of air at a given temperature.
temperature of a system approaches                     The hotter the air is, the more water it can
absolute zero (−273.15°C, 0 K), then the               contain.
value of the entropy approaches a                   Relative humidity : It is the ratio of the
minimum.                                               current absolute humidity to the highest
possible absolute humidity (which
depends on the current air temperature).
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