What is specific heat ?
Specific heat is a property that describes how much heat energy is required to raise the temperature of a substance by a certain amount. Specific heat is the amount of heat energy required to raise the temperature of one unit of mass of a substance by one degree Celsius (or one Kelvin). The specific heat of water is 4.186 joules per gram per degree Celsius, which means that it takes 4.186 joules of heat to raise the temperature of 1 gram of water by 1 degree Celsius.
The specific heat capacity (often simply referred to as specific heat) of a substance is determined by its internal structure and composition. Different substances have different specific heat values due to variations in their molecular or atomic structures. Substances with higher specific heat values require more energy to increase their temperature compared to substances with lower specific heat values.
It's worth noting that specific heat can vary with temperature. For some substances, the specific heat may change depending on the temperature range over which the measurements are taken. In such cases, average specific heat values are often used for calculations within a given temperature range.
Specific heat formula
In more technical terms, specific heat (often denoted as "C") is defined as the ratio of the heat energy transferred (Q) to the mass (m) of the substance and the change in temperature (ΔT):
The specific heat capacity can be expressed mathematically using the equation:
Q = mcΔT
- Q is the amount of heat energy transferred
- m is the mass of the substance
- c is the specific heat capacity of the substance
- ΔT is the change in temperature
This equation shows that the amount of heat energy (Q) transferred is directly proportional to the mass (m), specific heat capacity (c), and the change in temperature (ΔT).
C = Q / (m * ΔT)
The unit of specific heat depends on the system of measurement used. In the International System of Units (SI), the unit of specific heat is joules per kilogram per degree Celsius (J/kg°C) or (J/kg K). In the older metric system, the unit is calories per gram per degree Celsius (cal/g°C).
Specific heat is an important property of a substance because it can be used to calculate the amount of heat required to change the temperature of a substance. For example, if you want to know how much heat is required to raise the temperature of 1 liter of water from 20 degrees Celsius to 30 degrees Celsius, you can use the given equation.
In this case, the mass of the water is 1 liter, which is equal to 1000 grams. The specific heat of water is 4.186 joules per gram per degree Celsius. The change in temperature is 10 degrees Celsius (30 - 20 = 10).
Plugging these values into the equation, we get:
Q = 41860 J
Terefore, it takes 41860 joules of heat to raise the temperature of 1 liter of water from 20 degrees Celsius to 30 degrees Celsius.
Air specific heat calculator
The 'Air Specific Heat Calculator' can be used to quickly estimate specific heat or mass heat capacity of air in kJ/kg/K for the specified temperature and pressure conditions. The calculator is valid for pressure values between 1 - 250 bara and temperature values between 80 - 2500 K. The heat capacity value reported in this calculator is the specific heat of air at constant pressure CP.