In the first law of thermodynamics, △e = q-w, what does △e stand for?

a. the work done by the piston

b. the internal energy of the system

c. the heat added to the system

d. the change in the internal energy of the system

The correct answer is Option B.

Explanation:

First law of thermodynamics states that the energy can neither be destroyed not be formed but it can only be transformed from one form to another.

Here, the internal energy of the system is being transformed to the heat energy and the work done by the system. The equation used to represent first law of thermodynamic is:

where,

represents the internal energy of the system.

Q = heat released or absorbed by the system.

w = work done by or on the system.

Hence, the correct answer is Option B.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.