Why dry air is heavier than moist air?

Explanation

To understand why dry air is heavier than moist air, we can break down the explanation into a few clear steps:

### Step-by-Step Solution:

1. **Define Dry Air and Moist Air**:
- Dry air is the mixture of gases that makes up the atmosphere, primarily nitrogen (N₂) and oxygen (O₂), with an average molecular mass of about 28.9 g/mol.
- Moist air, on the other hand, is air that contains water vapor. The presence of water vapor affects the overall molecular mass of the air mixture.

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