Question

Can the temperature of a system remain constant even though heat flows into or out of it? If so, give examples.

Short answer

When the work done on the system is equal to the heat exchange between the system and the surrounding, the system's temperature remains constant.

Step-by-step solution

Concept

By the first law of thermodynamics,\(\Delta U = Q - W\).

The temperature remains constant in the isothermal process, and the change in internal energy is\(\Delta U = 0\).

Explanation

For the isothermal process,

\(\begin{aligned}{c}0 = Q - W\\Q = W.\end{aligned}\)

When the work done on the system is equal to the heat exchanged between the system and the surrounding, the system's temperature remains constant.

Also, melting and freezing are the cases where heat flows out or into the system without changing the temperature of the system.