Heat Capacity and Specific Heat Capacity
What is the difference between heat capacity and specific heat capacity?
Which one is used to quantitatively describe the amount of heat needed to change the temperature of a substance?
Answer:
The difference between heat capacity and specific heat capacity lies in their definitions and units. Heat capacity (C) is the amount of heat energy required to change the temperature of a substance by one degree Celsius or one Kelvin. It is measured in units of joules per degree Celsius (J/°C) or joules per Kelvin (J/K).
On the other hand, specific heat capacity (c) is the amount of heat energy required to change the temperature of one unit mass of a substance by one degree Celsius or one Kelvin. It is measured in units of joules per gram degree Celsius (J/g°C) or joules per gram Kelvin (J/gK).
Heat capacity is a macroscopic property that depends on the mass and chemical composition of a substance, while specific heat capacity is an intrinsic property that is unique to each substance. In other words, specific heat capacity is an intensive property, whereas heat capacity is an extensive property.
To quantitatively describe the amount of heat needed to change the temperature of a substance, specific heat capacity is used. It takes into account the mass of the substance and provides a more accurate measure of heat transfer compared to heat capacity.
For example, water has a high specific heat capacity of 4.18 J/g°C, which means that it requires a relatively large amount of heat energy to increase its temperature. This property of water plays a crucial role in regulating the Earth's climate and maintaining stable temperatures in aquatic environments.