Work and Heat

Work is mathematically expressed as the dot product of force and displacement vectors. It is a scalar quantity measured in Joules.

For a gas confined by a frictionless piston, work is performed on the surroundings as the piston moves outward, causing the gas to expand and reduce its internal energy. On the other hand, when the piston moves inward, work is done on the gas, compressing it and increasing its internal energy.

Total work is calculated by integrating the volume changes, assuming constant external pressure.

The ideal gas law is then used to calculate the work done during an isothermal reversible process involving an ideal gas.

Work interacts closely with heat as both influence a system’s internal energy. Heat is the transfer of thermal energy measured in joules or calories.

A system can either absorb or release heat, resulting in a change in its temperature.

The sign of 'q' shows the direction of heat transfer.

The amount of heat required for a temperature change depends on the mass, the temperature change, and the specific heat capacity, c, which shows the amount of heat needed to raise the temperature of a substance.

c, measured in J/g.K, is an intensive property characteristic of the system's material.