SECTION C Parts: 3.1-3.4
Specific Heat Capacity
 The specific heat capacity of a substance is the
amount of heat requires to increase the
temperature of unit mass of a substance by one
degree Celsius.
 Units- 1) c/J
2) Kg-1 K-1
Heat Capacity
 The heat capacity (C) of an object is defined as the
heat required to raise its temperature by one degree.
 The rise in temperature of a body which is heated,
without a change in state depends on :
the mass of the body. The nature of the substance of
which the body is made.
 the formula for heat capacity is C=mc
Where C is heat capacity, m is mass and c is the
specific heat capacity.
Specific Heat Capacity Formula
 Equal quantities in heat supplied to the same mass of a
given substance produce the same temperature rise.
 The temperature rise for a given quantity of heat supplied
depends on the mass of the substance involved.
 The same quantity of heat supplied to equal masses if
different substances results in different temperature
changes, depending on the different specific heat capacities
of the materials.
heat supplied = mass of substance X SHC X Temperature Rise
EH
= m (Kg) X c (J Kg-1 K-1 ) X Δθ (K)
Examples
1) How much energy is needed to heat 100g of water from
100C to 300C?
Specific heat capacity of water = 4200J/kg 0C.
mass of water = 100g = 0.1kg
temperature rise = 30 0C - 10 0C = 20 0C
Heat needed = SHC * mass * temperature rise
EH
= 4200 * 0.1 * 20 joule
= 4200 * 2 joule
= 8400 J
Determining Specific Heat Capacity
 To determine the specific heat capacity of a material be it a liquid or gas
two methods can be used:
 The Electrical method.
Method of mixtures.
The
Electrical method
To find the specific heat capacity of a substance using this method
would involve the use of a thermometer, water, beaker, electrical heater
and a stirring rod. In a determined volume of water , place an electrical
heater, turn it on and stir with the rod to keep the heat moving. All the
while a thermometer is should be in the water to determine the changes
of temperature for the allowed amount of time. The initial temperature
of the water and all temperature changes after the electrical heater was
turned on must be taken at regular intervals.
 The Method of Mixtures
When two objects at different temperatures are placed in
thermal contact, the hot object losses heat and the cold object gains
the heat lost by the hot object.
therefore we can say:
Heat lost by a hot object = Heat gained by a cold object
Method: Hot the water to boiling point, place a rod into it and leave it
for a few minutes until the rod is at the same temperature as the
water. The rod is then quickly taken out of the first beaker and
placed into a second beaker filled with water at room temperature.
Stir the water continuously to keep the heat moving. With the use of
a thermometer take the changes of temperature at regular intervals
until no more change is seen.
Formula: Heat gained by substance = Heat lost by other substance
m1* c1* Δθ1
= m2* c2* Δθ2
Example
1) A block of metal of mass 0.8 kg at 100 0C was placed in 0.4 kg of
water at 30 0C. The final steady temperature of the mixture was
43.5 0C. What is the specific heat capacity of the metal?
Temperature rise of water = (43.5 – 30) 0C = 13.5 0C
Temperature drop of the block = (100 – 43.5) 0C = 56.5 0C
Heat lost by block = Heat gained by water
m1* c1 * Δθ1
0.8 * c block* 56.5
c block
=
=
=
m2* c2* Δθ2
0.4 * 4200 * 13.5
502 J Kg-1 K-1
SECTION C Parts: 3.5, 3.6
States of Matter
Matter is anything in the universe that has a mass and
occupies space. The quantity of matter contained in an object
determines its mass. Since materials are made up of small
particles of simple substances, the quantity of matter in a
material depends on:
The quantity of matter in each individual particle of
each simple substance.
The way in which these particles are packed, i.e..whether
tightly or loosely packed
All matter be it any of the three states consists of atoms. An atom is
the smallest unit that can exist. The state of matter depends upon
the energy(kinetic energy) the atoms contained within the object
has. As a result changing the amount of energy the atoms has,
changes the state of the object
There are three states of matter:
 Solids
Liquids
Gases
Solids
Atoms within a solid are tightly packed due to the
strong intermolecular forces between them and as it
possess very small amounts of kinetic energy. Due to
these strong forces the shape of the solid is fixed as the
atoms can only vibrate about a point and the volume is
definite with very little compression or expansion
ability.
Liquids
Atoms within a liquid are randomly arranged with
small spaces between them. This is so as the
intermolecular forces are fairly weak and allows the atoms
to move slowly as it posses medium kinetic energy. Due to
this weak intermolecular force the shape of the liquid is
that of the container it is placed in with the surface always
being horizontal, and a definite volume. Liquids can be
expanded and compressed slightly
Gases
Atoms within a gas are randomly arranged with
large spaces between them. The intermolecular forces is
very weak and allows rapid movement since it posses a
large amount of Kinetic energy. Due to this weak force
the volume of the gas is variable meaning that it expands
to fill the container and takes the shape of the container.
Gases can be easily expanded or compressed.
Credits and Bibliography
 Heinemann Physics for CXC – Norman Lambert
 Practical Physics for CXC – Gillian Blackman-Herbert
 Physics for You – Keith Johnson
 ***Mr Ramdath notes
 http://en.wikipedia.org/wiki/Heat_capacity#Heat_capacity
 http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/spht.html#c1
 http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html#c1
Done By: Fadilah Khan
5C