Heat exchanged in a chemical in a chamical reaction at constant temperature and pressure is called

Options

A. entropy
B. Enthalpy
C. internal energy
D. free energy

Answer

B

Explanation

According to thermodynamics,
`Delta H = Delta U + P Delta V` (`T` and `P` constant)
`= q + ( - P Delta V) + P Delta V`
`= q` (`T`, `P` constant)
Thus, heat exchanged by the system with its surroundings at constant `T` and `P` is called enthalpy change. Hence, `Delta H` is sometimes called the heat of reaction at constant `P`.