Question

When the surroundings absorbs heat, is the heat change of the system (qsystem) positive or negative?

Answer 1

The correct answer is:

negative

In fact, the first law of thermodynamics is generally stated as follows:

`\Delta U = Q-W`

where

`\Delta U` is the variation of internal energy of a system

Q is the heat absorbed by the system from the surroundings

W is the work done by the system on the surroundings

Following this definition, Q is positive if the heat is absorbed by the system, while it is negative if the heat is released by the system (and therefore, absorbed by the surroundings), because in this case the internal energy of the system decreases.