Heat capacity and specific heat capacity
Heat capacity and specific heat capacity
Many experiments suggested that the amount of heat energy required to raise the temperature of a substance is directly proportional to:
1. mass (m)
2. change in temperature (??)
This can be expressed as,
Q = ms?? è1
Where, s is proportionality constant which is called specific heat capacity. Its value depends on the nature of the substance.
If ?? = 10C
Therefore,
Q = ms
This quantity of heat is called heat capacity or thermal capacity of a substance. It is defined as the amount of energy required to change the temperature of mass of the substance through 10C. its unit is called J/K in SI and calorie per Kelvin in CGS.
Again from equation 1
s = Q/m??
if m = 1 unit
?? = 1 unit
Then,
s = Q
So, the specific heat capacity of a substance is defined as the amount of heat energy required to change the temperature of unit mass through 10C. Its SI unit is J/kg0C.
For water,
S = 4200 J/kg0K (SI)
= 1 calg-1K-1
For ice,
S = 2100 J/kg0K
= 0.5 calg-1K-1