Chapter 1, Problem 1.21P

Interpretation Introduction

Interpretation:

The molar concentration of $0.2\text{ ppb}$ of $C_{20}{H}_{42}$ in a sample of rainwater has to be calculated.

Concept introduction:

Parts Per Billion refers to a term that expresses concentration of certain substance in a mixture of substances.   It is denoted as ppb.  It is represented as,

$ppb\text{ = }\frac{mass\text{ of substance}}{mass\text{ of sample}}\times {10}^9$

In solution concentrations, $1\text{ ppb}$ is equivalent to $1\text{ ng/mL or 1 }\mu \text{g/L}\text{.}$

Molarity is a concentration term that is used to express the concentration of the solute in solution.  It is represented as,

$molarity\text{ = }\frac{no.of\text{ moles of solute}}{volume\text{ of solution in L}}$