A balloon has 5.0 mole of helium at `7^(@)C`. Calculate
(a) the number of atoms of helium in the balloon.
(b) the total internal energy of the system.

Explanation

To solve the given problem step by step, we will break it down into two parts as specified in the question.

### Part (a): Calculate the number of atoms of helium in the balloon.

1. **Identify the number of moles of helium**:
- Given: Number of moles (n) = 5.0 moles.

2. **Use Avogadro's number**:
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