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.