Chapter 15, Problem 12A

(a)

Interpretation Introduction

Interpretation:

The percent by mass of solute is to be calculated.

Concept introduction:

The percent by mass of solute is calculated by using formula:

  $\%massofsolute=\frac{massofsolute}{massofsolution}\times 100$

Answer to Problem 12A

The percent by mass of solute is $7.88\%$

Explanation of Solution

Given:

Mass of solute (potassium chloride) = $2.14g$

Mass of solvent (water) = $25g$

Mass of solution=mass of solute + mass of solvent

= $2.14+25$

= $27.14g$ .

Calculations:

Substituting the values in the given formula:

  $\begin{array}{c}\%massofsolute=\frac{2.14}{27.14}\times 100\\ =7.88\%\end{array}$

(b)

Interpretation Introduction

Interpretation:

The percent by mass of solute is to be calculated.

Concept introduction:

The percent by mass of solute is calculated by using formula:

  $\%massofsolute=\frac{massofsolute}{massofsolution}\times 100$

Answer to Problem 12A

The percent by mass of solute is $14.62\%$

Explanation of Solution

Given:

Mass of solute (potassium chloride) = $2.14g$

Mass of solvent (water) = $12.5g$

Mass of solution=mass of solute + mass of solvent

= $2.14+12.5$

= $14.64g$ .

Calculations:

Substituting the values in the given formula:

  $\begin{array}{c}\%massofsolute=\frac{2.14}{14.64}\times 100\\ =14.62\%\end{array}$

(c)

Interpretation Introduction

Interpretation:

The percent by mass of solute is to be calculated.

Concept introduction:

The percent by mass of solute is calculated by using formula:

  $\%massofsolute=\frac{massofsolute}{massofsolution}\times 100$

Answer to Problem 12A

The percent by mass of solute is $5.4\%$

Explanation of Solution

Given:

Mass of solute (potassium chloride) = $2.14g$

Mass of solvent (water) = $37.5g$

Mass of solution=mass of solute + mass of solvent

= $2.14+37.5$

= $39.64g$ .

Calculations:

Substituting the values in the given formula:

  $\begin{array}{c}\%massofsolute=\frac{2.14}{39.64}\times 100\\ =5.4\%\end{array}$

(d)

Interpretation Introduction

Interpretation:

The percent by mass of solute is to be calculated.

Concept introduction:

The percent by mass of solute is calculated by using formula:

  $\%massofsolute=\frac{massofsolute}{massofsolution}\times 100$

Answer to Problem 12A

The percent by mass of solute is $4.10\%$

Explanation of Solution

Given:

Mass of solute (potassium chloride) = $2.14g$

Mass of solvent (water) = $50g$

Mass of solution=mass of solute + mass of solvent

= $2.14+50$

= $52.14g$ .

Calculations:

Substituting the values in the given formula:

  $\begin{array}{c}\%massofsolute=\frac{2.14}{52.14}\times 100\\ =4.10\%\end{array}$