Question

In a certain chemical process, a lab technician supplies 237 J of heat to a system. At the same time, 67.0 J of work are done on the system by its surroundings. What is the total energy change of the system?

1) 170 J
2) 304 J
3) 370 J
4) 470 J

Answer 1

The total energy change of the system, which includes 237 J of heat supplied and 67 J of work done on the system, is calculated as 304 J according to the First Law of Thermodynamics.

Step-by-step explanation:

The total energy change of the system is determined by the First Law of Thermodynamics, which states that the change in internal energy (ΔU) of a system is equal to the heat (Q) added to the system minus the work (W) done by the system on its surroundings. In this case, however, work is being done on the system, not by it, which means we need to add the work done on the system to the heat supplied to find the total energy change.

The technician supplies 237 J of heat to the system, and at the same time, 67.0 J of work are done on the system. Therefore, using the formula ΔU = Q + W (since work is done on the system), the total energy change (ΔU) is:

ΔU = Q + W

ΔU = 237 J + 67.0 J

ΔU = 304 J

So, the correct answer is 304 J, which corresponds to option 2.