Jin knows that the initial internal energy of a closed system is 78 j and the final internal energy is 180 j. he also knows that 64 j of energy are used to do work. to find the heat added to the system, jin completes the steps below. 1. add the initial internal energy plus the final internal energy to find the change in internal energy. 2. add the change in internal energy to the energy used to do work. 3. write the answer in joules.

The problem can be solved by using the first law of thermodynamics:

(1)

where

is the variation of internal energy

Q is the heat added to the system

W is the work done by the system

The variation of internal energy in this case is

The work done on the system is

with a negative sign since it is done by the environment on the system. Therefore, we can rearrange eq.(1) to find the heat added to the system:

idk sorry i only needs point for apex

explanation: