Chapter 5, Problem 5.49P

Interpretation Introduction

Interpretation:

The molar mass of a gas at $388\text{torr}$ and $45°\text{C}$ is to be calculated if $206\text{ng}$ of it occupies $0.206\text{μL}$.

Concept introduction:

Ideal gas law equation is as follows:

$PV=nRT$        (1)

Here,

$P$ is the pressure of the gas.

$V$ is the volume occupied by gas.

$n$ is the no. of moles of gas.

$T$ is the temperature in Kelvin.

$R$ is the universal gas constant.

The formula to calculate no. of moles is as follows:

$n=\frac{\text{weight}\left(m\right)}{\text{molecular}\text{weight}\left(M\right)}$

The ideal gas equation can be written as follows:

$PV=\frac{mRT}{M}$        (2)

The conversion factor to convert $°\text{C}$ to Kelvin is as follows:

$T\left(\text{K}\right)=T\left(°\text{C}\right)+273.15$        (3)

Conversion factor to convert $\text{torr}$ to $\text{atm}$ is as follows:

$\text{760}\text{torr}=\text{1}\text{atm}$

Conversion factor to convert microliters $\left(\text{μL}\right)$ to liters $\left(\text{L}\right)$ is as follows:

$\text{1}\text{μL}={\text{10}}^{-6}\text{L}$

Conversion factor to convert nanograms $\left(\text{ng}\right)$ to grams $\left(\text{g}\right)$ is as follows:

$\text{1}\text{ng}={10}^{-9}\text{g}$