Vapor Density of Gas
Vapor density is a measure of the density of a gas or vapor compared to the density of a reference gas. The reference gas is typically air, which is assigned a vapor density of 1. The vapor density of a gas is useful for various purposes, including determining whether a gas will rise or sink in air. Gases with a vapor density less than 1 are lighter than air and will tend to rise, while gases with a vapor density greater than 1 are heavier than air and will tend to sink.
Vapor density example
- Hydrogen gas (H2) has a molar mass of approximately 2 grams per mole, so its vapor density is 1 (2/2).
- Carbon dioxide gas (CO2) has a molar mass of approximately 44 grams per mole, so its vapor density is 22 (44/2), indicating that it is much heavier than air.
Vapor Density of Gas formula |
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\( G_{vd} = G \;/\; H \) (Vapor Density of Gas) \( G = G_{vd} \; H \) \( H = G \;/\; G_{vd} \) |
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| Symbol | English | Metric |
| \(\large{ G_{vd} }\) = Vapor Density of Gas | \(lbm \;/\; ft^3\) | \(kg \;/\; m^3\) |
| \(\large{ G }\) = Gas Density | \(lbm \;/\; ft^3\) | \(kg \;/\; m^3\) |
| \(\large{ H }\) = Hydrogen Density | \(lbm \;/\; ft^3\) | \(kg \;/\; m^3\) |
