Question

Suppose a system receives a "deposit" of work from the surroundings and loses a "withdrawal" of heat to the surroundings. Can we determine the sign of ΔE for this process?
A. No, because we are not given specific values for w and q.
B. No, because it an open system.
C. Yes, because we know the signs of w and q.
D. No, because we do not know the temperature of the system

Answer 1

Answer:

A. No, because we are not given specific values for w and q.

Explanation:

The change of internal energy of a system is:

ΔE = q + w

where q represents heat and w represents work.

It is necessary to know the magnitude and the sign of q and w in order to know if the system's internal energy is increasing or decreasing.