A tank contains 28.0 kg of `O_(2)` gas at a gauge pressure of 6.80 atm. If the oxygen is replaced by helium, how many kg of the latter will be needed to produce a gauge pressure of 8.25 atm ?

Explanation

To solve the problem, we need to apply the ideal gas law and the relationship between pressure, volume, and mass of gas. Here are the steps to find out how many kg of helium gas will be needed to achieve a gauge pressure of 8.25 atm.

### Step-by-Step Solution:

1. **Identify Given Values:**
- Mass of oxygen, \( M_1 = 28.0 \, \text{kg} \)
- Gauge pressure of oxygen, \( P_1 = 6.80 \, \text{atm} \)
- Gauge pressure of helium, \( P_2 = 8.25 \, \text{atm} \)
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