Specific Heat Capacity in Chemistry

What Is Specific Heat Capacity in Chemistry?

test tube being heated with flame
Specific heat capacity is energy needed to raise the temperature of a material one degree. WLADIMIR BULGAR / Getty Images

Specific Heat Capacity Definition

Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass. The specific heat capacity of a material is a physical property. It is also an example of an extensive property since its value is proportional to the size of the system being examined.

Key Takeaways: Specific Heat Capacity

  • Specific heat capacity is the quantity of heat needed to raise the temperature per unit mass.
  • Usually, it's the heat in Joules needed to raise the temperature of 1 gram of sample 1 Kelvin or 1 degree Celsius.
  • Water has an extremely high specific heat capacity, which makes it good for temperature regulation.

In ​SI units, specific heat capacity (symbol: c) is the amount of heat in joules required to raise 1 gram of a substance 1 Kelvin. It may also be expressed as J/kg·K. Specific heat capacity may be reported in the units of calories per gram degree Celsius, too. Related values are molar heat capacity, expressed in J/mol·K, and volumetric heat capacity, given in J/m3·K.

Heat capacity is defined as the ratio of the amount of energy transferred to a material and the change in temperature that is produced:

C = Q / ΔT

where C is heat capacity, Q is energy (usually expressed in joules), and ΔT is the change in temperature (usually in degrees Celsius or in Kelvin). Alternatively, the equation may be written:

Q = CmΔT

Specific heat and heat capacity are related by mass:

C = m * S

Where C is heat capacity, m is mass of a material, and S is specific heat. Note that since specific heat is per unit mass, its value does not change, no matter the size of the sample. So, the specific heat of a gallon of water is the same as the specific heat of a drop of water.

It's important to note the relationship between added heat, specific heat, mass, and temperature change does not apply during a phase change. The reason for this is because heat that is added or removed in a phase change does not alter the temperature.

Also Known As: specific heat, mass specific heat, thermal capacity

Specific Heat Capacity Examples

Water has a specific heat capacity of 4.18 J (or 1 calorie/gram °C). This is a much higher value than that of most other substances, which makes water exceptionally good at regulating temperature. In contrast, copper has a specific heat capacity of 0.39 J.

Table of Common Specific Heats and Heat Capacities

This chart of specific heat and heat capacity values should help you get a better sense of the types of materials that readily conduct heat versus those which do not. As you might expect, metals have relatively low specific heats.

Material Specific Heat
(J/g°C)
Heat Capacity
(J/°C for 100 g)
gold 0.129 12.9
mercury 0.140 14.0
copper 0.385 38.5
iron 0.450 45.0
salt (Nacl) 0.864 86.4
aluminum 0.902 90.2
air 1.01 101
ice 2.03 203
water 4.179 417.9

Sources

  • Halliday, David; Resnick, Robert (2013). Fundamentals of Physics. Wiley. p. 524.
  • Kittel, Charles (2005). Introduction to Solid State Physics (8th Ed.). Hoboken, New Jersey, USA: John Wiley & Sons. p. 141. ISBN 0-471-41526-X.
  • Laider, Keith J. (1993). The World of Physical Chemistry. Oxford University Press. ISBN 0-19-855919-4.
  • unus A. Cengel and Michael A. Boles (2010). Thermodynamics: An Engineering Approach (7th Edition). McGraw-Hill. ISBN 007-352932-X.