Question

Find the volume occupied by \(8\) g of a gas at STP if its vapour density is \(16\).

• A. \(2.8\) L
• B. \(5.6\) L
• C. \(11.2\) L
• D. \(22.4\) L

Hint:

Remember: VD \(= \frac{\text{Molar mass}}{2}\). At STP, \(1\) mole of any gas occupies \(22.4\) L.

Answer 1

The Correct Option is B

Concept: Vapour density (VD) is related to molar mass as: \[ \text{Molar mass} = 2 \times VD \] At STP, one mole of gas occupies \(22.4\) L.

Step 1: Find molar mass of the gas. \[ M = 2 \times 16 = 32 \]

Step 2: Find number of moles. \[ n = \frac{\text{given mass}}{\text{molar mass}} \] \[ n = \frac{8}{32} = 0.25 \]

Step 3: Calculate volume at STP. \[ V = n \times 22.4 \] \[ V = 0.25 \times 22.4 \] \[ V = 5.6 \text{ L} \] Thus, the volume occupied is \(5.6\) L.