High School

If a system has 46.5 J of heat added to it, and the system does 75.5 J of work on its surroundings, what is the change in the internal energy of the system, in J?

Answer :

Final answer:

The change in internal energy of the system is -29.0 J, with 46.5 J of heat added to it and 75.5 J of work done by it on the surroundings.

Explanation:

To determine the change in the internal energy of a system, we use the first law of thermodynamics which is expressed as ΔU = Q - W, where ΔU represents the change in internal energy, Q is the heat transfer to the system, and W is the work done by the system on its surroundings.

In this scenario, the system has 46.5 J of heat added to it (Q = 46.5 J) and does 75.5 J of work on its surroundings (W = 75.5 J). The change in internal energy (ΔU) can be calculated as:

ΔU = Q - W
ΔU = 46.5 J - 75.5 J
ΔU = -29.0 J

Therefore, the change in internal energy of the system is -29.0 J. This result indicates the system lost energy to its surroundings.