1. What is Vapor Density of Methane Gas?

Definition: Vapor density is the ratio of the molar mass of a gas to the molar mass of hydrogen gas under the same conditions.

Purpose: It helps determine whether a gas is heavier or lighter than air (hydrogen being the lightest gas).

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Vapor density (unitless)
• \( M \) — Molar mass of the gas (g/mol)
• \( M_{H_2} \) — Molar mass of hydrogen gas (2.02 g/mol)

Explanation: The formula compares the density of a gas to hydrogen gas at the same temperature and pressure.

3. Importance of Vapor Density

Details: Vapor density helps predict gas behavior - gases with VD < 1 will rise, while VD > 1 will sink in air.

4. Using the Calculator

Tips: Enter the molar mass of methane (default 16.04 g/mol) and hydrogen (default 2.02 g/mol). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the vapor density of methane?
A: Methane (CH₄) has a vapor density of about 8 (16.04/2.02 ≈ 8), meaning it's lighter than air.

Q2: Why use hydrogen as the reference?
A: Hydrogen is the lightest known gas, making it a useful reference point for comparing other gases.

Q3: How does vapor density relate to safety?
A: Gases with VD < 1 will disperse upward, while VD > 1 can accumulate in low areas, creating explosion hazards.

Q4: What's the vapor density of air?
A: Air has an average molar mass of ~28.97 g/mol, giving it VD ≈ 14.34 relative to hydrogen.

Q5: Can I calculate VD relative to air instead?
A: Yes, but the standard reference is hydrogen. For air, use VD_air = M/28.97.