Air doesn't have a single, fixed vapor density because it's a mixture of gases. However, we can calculate the average vapor density of air at standard conditions (0°C and 1 atm).

Here's how:

1. Composition of air:

* Nitrogen (N₂) - 78.08%

* Oxygen (O₂) - 20.95%

* Argon (Ar) - 0.93%

* Carbon dioxide (CO₂) - 0.04%

* Other trace gases (like neon, helium, etc.) - <0.01%

2. Molar masses of components:

* N₂ - 28 g/mol

* O₂ - 32 g/mol

* Ar - 40 g/mol

* CO₂ - 44 g/mol

3. Calculating the average molar mass of air:

* (0.7808 * 28) + (0.2095 * 32) + (0.0093 * 40) + (0.0004 * 44) = 28.96 g/mol (approximately)

4. Vapor Density:

* Vapor density is defined as the ratio of the mass of a given volume of a gas to the mass of the same volume of hydrogen gas at the same temperature and pressure.

* The molar mass of hydrogen (H₂) is 2 g/mol.

* Therefore, vapor density of air = (average molar mass of air) / (molar mass of hydrogen) = 28.96 g/mol / 2 g/mol = 14.48

So, the approximate vapor density of air at standard conditions is 14.48. This means that air is approximately 14.48 times denser than hydrogen gas.