A gaseous mixture contains 40% `H_(2)` and `60%` He, by volume. What
is the average molecular mass of mixture ?

Explanation

To find the average molecular mass of a gaseous mixture containing 40% \( H_2 \) and 60% \( He \) by volume, we can follow these steps:

### Step 1: Identify the molecular masses of the components
- The molecular mass of \( H_2 \) (hydrogen gas) is 2 g/mol (since each hydrogen atom has a mass of approximately 1 g/mol and there are 2 atoms in \( H_2 \)).
- The molecular mass of \( He \) (helium) is 4 g/mol.

### Step 2: Use the formula for average molecular mass
The average molecular mass of a mixture can be calculated using the formula:
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