jin knows that the initial internal energy of a closed system is 78 j and the final internal energy is 180…

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. which best describes jins error? for step 1, he should have used 180 j as the change in internal energy. for step 1, he should have subtracted 78 j from 180 j to find the change in internal energy. for step 2, he should have subtracted the change in internal energy from the energy used to do work. for step 2, he should have subtracted the energy used to do work from the change in internal energy.

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. which best describes jins error? for step 1, he should have used 180 j as the change in internal energy. for step 1, he should have subtracted 78 j from 180 j to find the change in internal energy. for step 2, he should have subtracted the change in internal energy from the energy used to do work. for step 2, he should have subtracted the energy used to do work from the change in internal energy.

Answer

Explanation:

Step1: Recall the formula for change in internal energy

The change in internal energy $\Delta U$ of a system is given by $\Delta U=U_{final}-U_{initial}$. Here, $U_{initial} = 78\ J$ and $U_{final}=180\ J$, so $\Delta U=180 - 78=102\ J$. Jin's error is in step - 1 where he added the initial and final internal energies instead of subtracting to find the change in internal energy.

Step2: Recall the first - law of thermodynamics

The first - law of thermodynamics is $\Delta U = Q - W$, where $Q$ is the heat added to the system and $W$ is the work done by the system. We know $\Delta U = 102\ J$ and $W = 64\ J$. Solving for $Q$, we get $Q=\Delta U+W$.

Answer:

The error is: For step 1, he should have subtracted 78 J from 180 J to find the change in internal energy.