Chapter 8, Problem 27Q

Interpretation Introduction

Interpretation:

For the given gases ${\text{N}}_{\text{2}}$ and $\text{He}$ behaving like ideal gas: the calculation of molar volume of ${\text{N}}_{\text{2}}$ at STP is $\text{22}\text{.42}\text{L/mol}$ should be explained, the comparison between molar volumes of ${\text{N}}_{\text{2}}$ and $\text{He}$ at STP are needed to be carried out, the molar volume of ${\text{N}}_{\text{2}}$ at ${\text{25}}^{\text{o}}\text{C}$ should be explained whether it is less than or greater than $\text{22}\text{.42}\text{L/mol}$ and the molar volume of ${\text{N}}_{\text{2}}$ collected over water at a total pressure of $\text{1atm}$ and ${\text{0}}^{\text{o}}\text{C}$ should be explained whether it is less than or greater than $\text{22}\text{.42}\text{L/mol}$ .

Concept introduction:

• STP: standard temperature and pressure, it is the condition of ${\text{0}}^{\text{o}}C$ and 1 atm.

  The molar volume of gases at STP condition is similar and it is close to the molar volume of an ideal gas at STP condition. That is, 22.42 L. Hence, at STP the molar volume of a gas is considered as 22.42L.

• Volume of a gas, according to ideal gas equation,

$\text{Volume}\text{=}\frac{\text{Number}\text{of}\text{moles}\times \text{R}\text{×}\text{Temperature}}{\text{Pressure}}$

• Partial pressure of a gas in a mixture of gases is the pressure of that gas when it alone.
• Total pressure of a flask containing mixture of gases is the sum of individual partial pressures of constituted gases.