Chapter 22, Problem 22.21QP

(a)

Interpretation Introduction

To determine: The concentration of copper expressed in parts per million.

Interpretation: The amount of copper in milligrams is given to be present in given mass. Its concentration is to be calculated in parts per million.

Concept introduction: Parts per million by mass is the amount of solute in milligrams present in one kilogram of the substance.

Therefore, the concentration in $\text{ppm}$ is calculated by the formula,

$\text{Concentration}\text{in}\text{ppm}=\frac{\text{Mass}\text{of}\text{solute}\text{in}\text{milligrams}}{\text{Mass}\text{of}\text{solvent}\text{in}\text{kilograms}}$

Answer to Problem 22.21QP

The concentration of copper expressed in parts per million is $\underset{\_}{1.57ppm}$.

Explanation of Solution

Given

The mass of cooper is $110\text{mg}$.

The mass of the body is $70\text{kg}$.

The concentration in $\text{ppm}$ is calculated by the formula,

$\text{Concentration}\text{in}\text{ppm}=\frac{\text{Mass}\text{of}\text{solute}\text{in}\text{milligrams}}{\text{Mass}\text{of}\text{solvent}\text{in}\text{kilograms}}$

Substitute the value of mass of copper and body in the above equation.

$\begin{array}{c}\text{Concentration}\text{in}\text{ppm}=\frac{110\text{mg}}{70\text{kg}}\\ =1.57\text{ppm}\end{array}$

Therefore, the parts per million of copper is $\underset{\_}{1.57ppm}$.

(b)

Interpretation Introduction

To determine: The concentration of zinc expressed in parts per million.

Interpretation: The concentration of zinc in grams per kilogram of solvent. Its concentration is to be calculated in parts per million.

Concept introduction: Parts per million by mass is the amount of solute in milligrams present in one kilogram of the substance.

Therefore, the concentration in $\text{ppm}$ is calculated by the formula,

$\text{Concentration}\text{in}\text{ppm}=\frac{\text{Mass}\text{of}\text{solute}\text{in}\text{milligrams}}{\text{Mass}\text{of}\text{solvent}\text{in}\text{kilograms}}$

Answer to Problem 22.21QP

The concentration of zinc expressed in parts per million is $\underset{\_}{33ppm}$.

Explanation of Solution

Given

The concentration of zinc in grams per kilogram is $3.3\times {10}^{-2}\text{g}/\text{kg}$.

Parts per million by mass is the amount of solute in milligrams present in one kilogram of the substance.

One gram is equal to $1000$ milligram.

Therefore, $3.3\times {10}^{-2}\text{g}/\text{kg}$ is equal to $33\text{mg}/\text{kg}$.

Thus, the concentration of zinc is $\underset{\_}{33ppm}$.

(c)

Interpretation Introduction

To determine: The concentration of iodine expressed in parts per million.

Interpretation: The amount of iodine in grams is given to be present in given mass. Its concentration is to be calculated in parts per million.

Concept introduction: Parts per million by mass is the amount of solute in milligrams present in one kilogram of the substance.

Therefore, the concentration in $\text{ppm}$ is calculated by the formula,

$\text{Concentration}\text{in}\text{ppm}=\frac{\text{Mass}\text{of}\text{solute}\text{in}\text{milligrams}}{\text{Mass}\text{of}\text{solvent}\text{in}\text{kilograms}}$

Answer to Problem 22.21QP

The concentration of iodine expressed in parts per million is $\underset{\_}{0.43ppm}$.

Explanation of Solution

Given

The mass of iodine is $0.043\text{g}$.

The mass of the body is $100\text{kg}$.

One gram is equal to $1000$ milligram.

Therefore, $0.043\text{g}$ is equal to $43\text{mg}$.

The concentration in $\text{ppm}$ is calculated by the formula,

$\text{Concentration}\text{in}\text{ppm}=\frac{\text{Mass}\text{of}\text{solute}\text{in}\text{milligrams}}{\text{Mass}\text{of}\text{solvent}\text{in}\text{kilograms}}$

Substitute the value of mass of iodine and body in the above equation.

$\begin{array}{c}\text{Concentration}\text{in}\text{ppm}=\frac{43\text{mg}}{100\text{kg}}\\ =0.43\text{ppm}\end{array}$

Therefore, the parts per million of iodine is $\underset{\_}{0.43ppm}$.

Conclusion

1. a. The concentration of copper expressed in parts per million is $\underset{\_}{1.57ppm}$.
2. b. The concentration of zinc expressed in parts per million is $\underset{\_}{33ppm}$.
3. c. The concentration of iodine in parts per million is $\underset{\_}{0.43ppm}$.