If a system has 475 kcal of work done to it, and releases 5.00 * 102 kJ of heat into its surroundings, what is the change in internal energy of the system?

First, we convert kcal to joules:

1 kcal = 4.184 kJ

475 kcal = 1987.4 kJ

Now, calculating the change in internal energy:

ΔU = Q + W; where Q is the heat supplied to the system and W is the work done on the system.

ΔU = - 500 + 1987.4

ΔU = 1487.4 kJ