What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it?
To calculate the change in internal energy of a system, you can use the first law of thermodynamics, which states:
ΔU = Q - W
Where:
ΔU is the change in internal energy
Q is the heat absorbed by the system from its surroundings
W is the work done on the system
In this case, you are given that the system absorbs 0.677 kJ of heat (Q), and has 0.438 kcal of work done on it (W). To make the units consistent, you need to convert kcal to kJ:
1 kcal = 4.184 kJ
Therefore, 0.438 kcal = 0.438 * 4.184 kJ = 1.829 kJ.
Now you can substitute the given values into the equation:
ΔU = Q - W
ΔU = 0.677 kJ - 1.829 kJ
Subtracting the two values, you get:
ΔU = -1.152 kJ
Therefore, the change in internal energy of the system is -1.152 kJ.