Chapter 5, Problem 142CWP

Interpretation Introduction

Interpretation:

The mass of argon remaining in the given cylinder is needed to be determined if the initial number of moles of argon is $\text{150}\text{mol}$ at ${\text{25}}^{\text{o}}\text{C}$ and a pressure of $\text{8}\text{.93}\text{MPa}$ is used up to a pressure of $\text{2}\text{MPa}$ at ${19}^{\text{o}}\text{C}$.

Concept introduction:

• According to ideal gas law,

  If the volume of gas is constant, then the pressure is directly proportional to temperature and number of moles.

$\frac{\text{P}}{\text{nT}}\text{=}\frac{\text{R}}{\text{V}}$ , P,T and n are proportional.

Mathematically for a gas,

$\frac{{\text{P}}_{\text{initial}}}{{\text{n}}_{\text{initial}}{\text{T}}_{\text{initial}}}\text{=}\frac{{\text{P}}_{\text{final}}}{{\text{n}}_{\text{final}}{\text{T}}_{\text{final}}}$

• Mass of a substance from its number of moles is,

$\text{Number of moles}\text{×}\text{Molecular}\text{mass in grams}\text{=}\text{Mass }$