Chapter U3, Problem 19STP

Interpretation Introduction

Interpretation:

Number of moles of Nitrogen gas $\left({\text{N}}_{\text{2}}\right)$ in a container needs to be determined.

Concept introduction:

STP:

It means standard temperature and pressure, where temperature is $0^{\text{o}}\text{C or 273K}$ and the pressure is $\text{1}$ atmosphere.

1 mole of any gas at STP has volume  $=\text{22}.\text{4} \text{L}.$

Mole Concept:

$\text{22}.\text{4 L}$ of the gas at STP = $\text{1 mol}$

Thus, V L of the gas has number of moles = $\frac{\text{V}}{\text{22}\text{.4}}\text{ mol}$

Answer to Problem 19STP

Number of moles of Nitrogen gas = 0.5 mole.

Explanation of Solution

The formula for the mole number of the gas = $\frac{\text{volume(V) of the gas at STP}}{\text{22}\text{.4}}\text{ mol}$

Given, the Volume (V) of N₂ gas $=\text{11}.\text{2 L}$

By the above formula the number of moles of N₂ gas = $\frac{\text{11}\text{.2}}{\text{22}\text{.4}}\text{=0}\text{.5 mol}$

The Correct option is (B).

Number of moles of ${\text{N}}_{\text{2}}$ gas $\text{=0}\text{.5 mol}$.