An isolated system has an internal energy of 800 g. If there is no color transfer and no work, what is the change in internal energy?

Solution:
1. Given:
* Internal energy of the system: U = 800 \, \text{J}
* No heat transfer: Q = 0
* No work done: W = 0

2. Use the first law of thermodynamics:
* \Delta U = Q - W

3. Substitute the given values:
* Since both Q = 0 and W = 0, we have:
\Delta U = 0 - 0

4. Simplify:
* \Delta U = 0 \, \text{J}

Hence, the change in internal energy is:
* \Delta U = 0 \, \text{J}.