Chapter 7, Problem 7.80AP

(a)

Interpretation Introduction

Interpretation:

The concentration in parts per million of copper has to be calculated.

Concept Introduction:

Parts per million:  The parts per million is calculated using the formula,

  $\text{ppm=}\frac{\text{Mass}\text{of}\text{solute}\left(\text{g}\right)}{\text{Mass}\text{of}\text{solution}\left(\text{g}\right)}{\text{×10}}^{\text{6}}$

Answer to Problem 7.80AP

The concentration in parts per million of copper is $\text{1}\text{.3ppm}\text{Cu}\text{.}$

Explanation of Solution

Given,

Mass of the solute=$\text{1300μg}$

Mass of the solution=$\text{1kg}$

Microgram is converted into grams,

  $\begin{array}{l}\text{g=1300μgCu×}\frac{\text{1}\text{g}}{\text{1000,000μg}}\\ \text{g=0}\text{.0013gCu}\end{array}$

Kilograms to gram is converted as,

  $\begin{array}{l}\text{g=1kg×}\frac{\text{1000}\text{g}}{\text{1kg}}\\ \text{g=1000g}\end{array}$

The concentration in parts per million is calculated as,

  $\begin{array}{l}\text{ppm=}\frac{\text{Mass}\text{of}\text{solute}\left(\text{g}\right)}{\text{Mass}\text{of}\text{solution}\left(\text{g}\right)}{\text{×10}}^{\text{6}}\\ \text{ppm=}\frac{\text{0}\text{.0013g}}{\text{1000}\text{g}}{\text{×10}}^{\text{6}}\\ \text{ppm=1}\text{.3ppmCu}\end{array}$

The concentration in parts per million of copper is $\text{1}\text{.3ppm}\text{Cu}\text{.}$

(b)

Interpretation Introduction

Interpretation:

The concentration in parts per million of arsenic has to be calculated.

Concept Introduction:

Refer to part (a).

Answer to Problem 7.80AP

The concentration in parts per million of arsenic $\text{0}\text{.01ppm}\text{As}\text{.}$

Explanation of Solution

Given,

Mass of the solute=$\text{10μg}$

Mass of the solution=$\text{1}\text{.0 kg}$

Microgram is converted into grams,

  $\begin{array}{l}\text{g=10μg}\text{As×}\frac{\text{1}\text{g}}{\text{1000,000μg}}\\ \text{g=0}\text{.00001g}\text{As}\end{array}$

Kilograms is converted into grams,

  $\begin{array}{l}\text{g=1}\text{.0}\text{kg×}\frac{\text{1000}\text{g}}{\text{1kg}}\\ \text{g=1000 g}\end{array}$

The concentration in parts per million is calculated as,

  $\begin{array}{l}\text{ppm=}\frac{\text{Mass}\text{of}\text{solute}\left(\text{g}\right)}{\text{Mass}\text{of}\text{solution}\left(\text{g}\right)}{\text{×10}}^{\text{6}}\\ \text{ppm=}\frac{\text{0}\text{.00001g}}{\text{1000}\text{g}}{\text{×10}}^{\text{6}}\\ \text{ppm=0}\text{.01}\text{ppm}\text{As}\end{array}$

The concentration in parts per million of arsenic $\text{0}\text{.01ppm}\text{As}\text{.}$

(c)

Interpretation Introduction

Interpretation:

The concentration in parts per million of chromium has to be calculated.

Concept Introduction:

Refer to part (a).

Answer to Problem 7.80AP

The concentration in parts per million of chromium $\text{0}\text{.1ppm}\text{Cr}\text{.}$

Explanation of Solution

Given,

Mass of the solute=$\text{10μg}$

Mass of the solution=$\text{1}\text{.0 kg}$

Microgram is converted into grams,

  $\begin{array}{l}\text{g=100μg}\text{Cr×}\frac{\text{1}\text{g}}{\text{1000,000μg}}\\ \text{g=0}\text{.0001g}\text{Cr}\end{array}$

Kilograms is converted into grams,

  $\begin{array}{l}\text{g=1}\text{.0}\text{kg×}\frac{\text{1000}\text{g}}{\text{1kg}}\\ \text{g=1000 g}\end{array}$

The concentration in parts per million is calculated as,

  $\begin{array}{l}\text{ppm=}\frac{\text{Mass}\text{of}\text{solute}\left(\text{g}\right)}{\text{Mass}\text{of}\text{solution}\left(\text{g}\right)}{\text{×10}}^{\text{6}}\\ \text{ppm=}\frac{\text{0}\text{.0001g}}{\text{1000}\text{g}}{\text{×10}}^{\text{6}}\\ \text{ppm=0}\text{.1}\text{ppm}\text{Cr}\end{array}$

The concentration in parts per million of arsenic $\text{0}\text{.1ppm}\text{Cr}\text{.}$