Question

What does $C$ mean in $Q{\text{ = MCT}}$.

Answer 1

The relationship between the heat transfer and the temperature contained in this relation. It follows the first law of thermodynamics. $C$ is a constant value which is specified for each element. This formula will give us the value of the amount of energy.

Complete answer:
There is a relation between the amount of heat which is transferred and the change in the temperature. This relationship is given by the following:
$Q{\text{ = M }} \times {\text{ C }} \times {\text{ }}\Delta {\text{T}}$
Here Q is the amount of heat transfer , M is the mass of the substance and $\Delta T$ is the change in temperature and the last term C is the specific heat capacity of the substance.
The specific heat capacity of the substance may be defined as the amount of the heat per unit mass required to raise the temperature by one degree Celsius $\left( {{1^ \circ }C} \right)$. This definition comes from the following conversion:
$Q{\text{ = M }} \times {\text{ C }} \times {\text{ }}\Delta {\text{T}}$
$C{\text{ = }}\dfrac{{Q{\text{ }}}}{{M{\text{ }} \times {\text{ }}\Delta {\text{T}}}}$
Thus we can also derive the units by using the formula which is $J{\text{ k}}{{\text{g}}^{ - 1}}{\text{ }}{{\text{K}}^{ - 1}}$. The practical application of this specific heat is when we add a hot substance which does not melt in water. Thus here the temperature of water rises while the temperature of the substance gets reduced. The heat which is lost by the substance is now equal to the heat gained by the water.

Note:
The sign of the Q tells us about the difference of the energy in the initial system and the final system. If Q is negative then the energy released to surroundings while it comes out to positive then the energy is absorbed by the system.