Specific Heat
Capacity
CHAPTER 2.2.2
Internal Energy
Internal Energy = The Sum of Potential Energy
and Kinetic Energy
Measure of the Kinetic Energy of a particle =
Temperature
Specific Heat Capacity vs Thermal Capacity
Thermal capacity
Specific Heat Capacity
The thermal capacity of a body is
the quantity of heat needed to
raise the temperature of the whole
body by 1 °C
The specific heat capacity of a
substance is the amount of heat
required to produce a 1 ºC rise in 1
kg.
Thermal capacity is measured in
joules per ºC, i.e. J/ºC.
Unit of specific heat capacity is the
joule per kilogram per ºC,
i.e. J/(kg ºC).
The heat equation
heat received or given out = mass × temperature change × specific heat capacity
In symbols ∆E = m × ∆θ × c
Specific Heat
Capacities
How to measure the specific heat Capacity of Water?
Hint:
Electric Energy=
Electric Power X
time
∆E = m × ∆θ × c
P X ∆t = m × ∆θ × c
Importance of the high specific heat capacity
of water
Why water is used as a coolant?
1. A tank holding 60 kg of water is heated by a 3 kW electric immersion
heater. If the specific heat capacity of water is 4200 J/(kg ºC), estimate the
time for the temperature to rise from 10 ºC to 60 ºC.
2. A piece of aluminium of mass 0.5 kg is heated to 100 ºC and then placed in
0.4 kg of water at 10 ºC. If the resulting temperature of the mixture is 30 ºC, what
is the specific heat capacity of aluminium if that of water is 4200 J/(kg ºC)?
3. An electric kettle rated at 3kW containing 1kg of water is switched on.
If the specific heat capacity of water is 4200J/(kg°C), estimate the time
for the water temperature to rise from 30°C to 100°C.
4 A metal sphere of mass 100g is heated to 100°C and then placed in 200g
of water at 20°C. If the resulting temperature of the mixture is 25°C, what is
the specific heat capacity of the metal if that of water is 4200J/(kg°C)?