Chapter 8, Problem 117E

Interpretation Introduction

Interpretation: For the given data, partial pressure and number of atoms per cubic centimeter of Helium atoms should be determined.

Concept introduction:

• Partial pressure of a gas in a mixture of gases is the pressure of that gas when it alone.

  Partial pressure of a gas in terms of its mole fraction ( ${\text{χ}}_{\text{A}}$ ) and total pressure is,

${\text{P}}_{\text{A}}\text{=}{\text{χ}}_{\text{A}}\text{×}{\text{P}}_{\text{TOTAL}}$

• By combining the three gaseous laws namely Boyle’s law, Charles’s law and Avogadro’s law a combined gaseous equation is obtained. This combined gaseous equation is called Ideal gas law.

According to ideal gas law,

$PV=nRT$

Where,

P = pressure in atmospheres

V= volumes in liters

n = number of moles

R =universal gas constant ( $\text{0}\text{.08206L×atm/K×mol}$)

T = temperature in kelvins

Total number of moles of gases in the mixture of gases can be determined by using ideal gas equation.

According to ideal gas equation,

$\text{Total number}\text{of}\text{moles}\text{=}\frac{\text{Total pressure}\times \text{Volume}}{\text{R}\text{×}\text{Temperature}}$