Difference Between Specific Heat and Heat Capacity

The main difference between specific heat and heat capacity is that specific heat is the amount of energy needed to raise the temperature of a given sample by 1 K while heat capacity is the amount of energy needed to raise the temperature of 1 kg of substance by 1 K.

Specific heat and heat capacity both describe the amount of energy needed to raise the temperature of a substance.

Key Areas Covered

1. What is Specific Heat
      – Definition
2. What is Heat Capacity
      – Definition, Calculation
3. Difference Between Specific Heat and Heat Capacity
      – Comparison of Key Differences

Key Terms

Specific Heat, Heat Capacity

What is Heat Capacity

Heat capacity describes the amount of heat needed to raise the temperature of a given sample of a substance by 1 degree Celsius or 1 Kelvin (raising the temperature by 1^oC is the same as raising the temperature by 1 K). Units for measuring specific heat are J ^oC^-1 or J K^-1.

What is Specific Heat

Specific heat describes the amount of heat required to raise the temperature of a kilogram of a substance by 1^oC or 1 K. In some fields, the amount of heat required to raise the temperature by 1 gram is also often considered.

If a substance having a mass $m$ is given an energy $Q$ , and this results in a gain in temperature $\Delta T$ the specific heat is given by:

$c=\frac{Q}{m\Delta T}$

The units for specific heat capacity are J kg^-1 ^oC^-1 or J kg^-1 K^-1. The descriptions of heat capacity and specific heat work in the same way for a reduction in temperature by 1^oC or 1 K. Specific heat capacity itself changes with the temperature. This means that the heat capacity varies, as well. However, for relatively small changes in temperature, the variation in heat capacity can be ignored. At room temperature, for example, water has a specific heat of about 4200 J kg^-1 ^oC^-1. This is a comparatively high specific heat, meaning that the amount of energy required to raise the temperature of water by a given amount is also quite high. This fact is extremely useful in regulating the temperatures of “warm-blooded” animals.

Another related quantity is molar heat capacity, which describes the amount of energy needed to raise the temperature of 1 mole of a substance by 1^oC or 1 K.

Difference Between Specific Heat and Heat Capacity

Definition

Heat capacity gives the amount of energy required to raise the temperature of a given sample of a substance by 1°C, while specific heat gives the heat capacity per kilogram of a substance.

Mass Dependence

Heat capacity is directly proportional to the mass of an object, while specific heat does not depend on the mass of an object, as it is defined per unit mass.

Units

Moreover, heat capacity has SI units J K^-1while specific heat has SI units J kg^-1 K^-1.

Conclusion

The main difference between specific heat and heat capacity is that specific heat is the amount of energy needed to raise the temperature of a given sample by 1 K while heat capacity is the amount of energy needed to raise the temperature of 1 kg of substance by 1 K.