Answer:
the heat exchange between the system and the surrounding medium
Step-by-step explanation:
The first law of thermodynamics states that: "Energy can neither be created nor destroyed, but can convert from one form to another"
It is represented mathematically as:
Δ e=q-w
where:
Δ e is the total change in the system's internal energy
q is the heat exchange between the system and the surrounding medium
w is the work done either on the system or by the system
Hope this helps :)