Chapter 15, Problem 46QAP

Interpretation Introduction

(a)

Interpretation:

The mass of the indicated solute in the given solution is to be calculated.

Concept Introduction:

The atomic mass of an element is defined as the sum of number of protons and number of neutrons. Molar mass of an element is determined from atomic mass of an element.

The number of moles is calculated by the formula,

$\text{Moles}=\frac{\text{Mass}\left(\text{g}\right)}{\text{Molar}\text{mass}}$

The molarity is calculated by the formula,

$\text{Molarity}=\frac{\text{Number}\text{of}\text{moles}\text{of}\text{solute}}{\text{Volume}\text{of}\text{solution}}$.

Answer to Problem 46QAP

The mass of the indicated solute in ${\text{CaCl}}_2$ solution is $0.233\text{g}$.

Explanation of Solution

It is given that $17.8\text{mL}$ of $0.119\text{M}$

${\text{CaCl}}_2$ solution is prepared.

The conversion of units of volume into $\text{L}$ is done as,

$\begin{array}{c}17.8\text{mL}=\frac{17.8}{1000}\text{L}\\ =0.0178\text{L}\end{array}$

The molar mass of ${\text{CaCl}}_2$ is $110.98\text{g}/\text{mol}$.

The number of moles of a solute is calculated by the formula,

$\text{Number}\text{of}\text{moles}\text{of}\text{solute}=\text{Volume}\text{of}\text{solution}\times \text{Molarity}$

Substitute the values of volume of solution and molarity of ${\text{CaCl}}_2$ solution in the above expression.

$\begin{array}{c}\text{Number}\text{of}\text{moles}\text{of}\text{solute}=0.0178\text{L}\times 0.119\text{M}\\ =0.0021\text{moles}\end{array}$

The mass of ${\text{CaCl}}_2$ is calculated by the formula,

${\text{Mass of CaCl}}_2=\text{Molar}\text{mass}\times \text{Number}\text{of}\text{moles}$

Substitute the values of molar mass and number of moles of ${\text{CaCl}}_2$ in the above expression.

$\begin{array}{c}{\text{Mass of CaCl}}_2=110.98\text{g}/\text{mol}\times 0.0021\text{moles}\\ =0.233\text{g}\end{array}$

Therefore, the mass of the indicated solute in ${\text{CaCl}}_2$ solution is $0.233\text{g}$.

Interpretation Introduction

(b)

Interpretation:

The mass of the indicated solute in the given solution is to be calculated.

Concept Introduction:

The atomic mass of an element is defined as the sum of number of protons and number of neutrons. Molar mass of an element is determined from atomic mass of an element.

The number of moles is calculated by the formula,

$\text{Moles}=\frac{\text{Mass}\left(\text{g}\right)}{\text{Molar}\text{mass}}$

The molarity is calculated by the formula,

$\text{Molarity}=\frac{\text{Number}\text{of}\text{moles}\text{of}\text{solute}}{\text{Liters}\text{of}\text{solution}}$.

Answer to Problem 46QAP

The mass of the indicated solute in $\text{KCl}$ solution is $0.589\text{g}$.

Explanation of Solution

It is given that $27.6\text{mL}$ of $0.288\text{M}$

$\text{KCl}$ solution is prepared.

The conversion of units of volume into $\text{L}$ is done as,

$\begin{array}{c}27.6\text{mL}=\frac{27.6}{1000}\text{L}\\ =0.0276\text{L}\end{array}$

The molar mass of $\text{KCl}$ is $74.55\text{g}/\text{mol}$.

The number of moles of a solute is calculated by the formula,

$\text{Number}\text{of}\text{moles}\text{of}\text{solute}=\text{Volume}\text{of}\text{solution}\times \text{Molarity}$

Substitute the values of volume of solution and molarity of $\text{KCl}$ solution in the above expression.

$\begin{array}{c}\text{Number}\text{of}\text{moles}\text{of}\text{solute}=0.0276\text{L}\times 0.288\text{M}\\ =0.0079\text{moles}\end{array}$

The mass of $\text{KCl}$ is calculated by the formula,

$\text{Mass of KCl}=\text{Molar}\text{mass}\times \text{Number}\text{of}\text{moles}$

Substitute the values of molar mass and number of moles of $\text{KCl}$ in the above expression.

$\begin{array}{c}\text{Mass of KCl}=74.55\text{g}/\text{mol}\times 0.0079\text{moles}\\ =0.589\text{g}\end{array}$

Therefore, the mass of the indicated solute in $\text{KCl}$ solution is $0.589\text{g}$.

Interpretation Introduction

(c)

Interpretation:

The mass of the indicated solute in the given solution is to be calculated.

Concept Introduction:

The atomic mass of an element is defined as the sum of number of protons and number of neutrons. Molar mass of an element is determined from atomic mass of an element.

The number of moles is calculated by the formula,

$\text{Moles}=\frac{\text{Mass}\left(\text{g}\right)}{\text{Molar}\text{mass}}$

The molarity is calculated by the formula,

$\text{Molarity}=\frac{\text{Number}\text{of}\text{moles}\text{of}\text{solute}}{\text{Liters}\text{of}\text{solution}}$.

Answer to Problem 46QAP

The mass of the indicated solute in ${\text{FeCl}}_{\text{3}}$ solution is $2.287\text{g}$.

Explanation of Solution

It is given that $35.4\text{mL}$ of $0.399\text{M}$

${\text{FeCl}}_3$ solution is prepared.

The conversion of units of volume into $\text{L}$ is done as,

$\begin{array}{c}35.4\text{mL}=\frac{35.4}{1000}\text{L}\\ =0.0354\text{L}\end{array}$

The molar mass of ${\text{FeCl}}_{\text{3}}$ is $162.2\text{g}/\text{mol}$.

The number of moles of a solute is calculated by the formula,

$\text{Number}\text{of}\text{moles}\text{of}\text{solute}=\text{Volume}\text{of}\text{solution}\times \text{Molarity}$

Substitute the values of volume of solution and molarity of ${\text{FeCl}}_{\text{3}}$ solution in the above expression.

$\begin{array}{c}\text{Number}\text{of}\text{moles}\text{of}\text{solute}=0.0354\text{L}\times 0.399\text{M}\\ =0.0141\text{moles}\end{array}$

The mass of ${\text{FeCl}}_{\text{3}}$ is calculated by the formula,

${\text{Mass of FeCl}}_{\text{3}}=\text{Molar}\text{mass}\times \text{Number}\text{of}\text{moles}$

Substitute the values of molar mass and number of moles of ${\text{FeCl}}_{\text{3}}$ in the above expression.

$\begin{array}{c}{\text{Mass of FeCl}}_{\text{3}}=162.2\text{g}/\text{mol}\times 0.0141\text{moles}\\ =2.287\text{g}\end{array}$

Therefore, the mass of the indicated solute in ${\text{FeCl}}_{\text{3}}$ solution is $2.287\text{g}$.

Interpretation Introduction

(d)

Interpretation:

The mass of the indicated solute in the given solution is to be calculated.

Concept Introduction:

The atomic mass of an element is defined as the sum of number of protons and number of neutrons. Molar mass of an element is determined from atomic mass of an element.

The number of moles is calculated by the formula,

$\text{Moles}=\frac{\text{Mass}\left(\text{g}\right)}{\text{Molar}\text{mass}}$

The molarity is calculated by the formula,

$\text{Molarity}=\frac{\text{Number}\text{of}\text{moles}\text{of}\text{solute}}{\text{Liters}\text{of}\text{solution}}$.

Answer to Problem 46QAP

The mass of the indicated solute in ${\text{KNO}}_3$ solution is $2.608\text{g}$.

Explanation of Solution

It is given that $46.1\text{mL}$ of $0.559\text{M}$

${\text{KNO}}_3$ solution is prepared.

The conversion of units of volume into $\text{L}$ is done as,

$\begin{array}{c}46.1\text{mL}=\frac{46.1}{1000}\text{L}\\ =0.0461\text{L}\end{array}$

The molar mass of ${\text{KNO}}_3$ is $101.10\text{g}/\text{mol}$.

The number of moles of a solute is calculated by the formula,

$\text{Number}\text{of}\text{moles}\text{of}\text{solute}=\text{Volume}\text{of}\text{solution}\times \text{Molarity}$

Substitute the values of volume of solution and molarity of ${\text{KNO}}_3$ solution in the above expression.

$\begin{array}{c}\text{Number}\text{of}\text{moles}\text{of}\text{solute}=0.0461\text{L}\times 0.559\text{M}\\ =0.0258\text{moles}\end{array}$

The mass of ${\text{KNO}}_3$ is calculated by the formula,

${\text{Mass of KNO}}_3=\text{Molar}\text{mass}\times \text{Number}\text{of}\text{moles}$

Substitute the values of molar mass and number of moles of ${\text{KNO}}_3$ in the above expression.

$\begin{array}{c}{\text{Mass of KNO}}_3=101.10\text{g}/\text{mol}\times 0.0258\text{moles}\\ =2.608\text{g}\end{array}$

Therefore, the mass of the indicated solute in ${\text{KNO}}_3$ solution is $2.608\text{g}$.