Chapter 6.2, Problem 2RQ

(a)

Interpretation Introduction

Interpretation: The molar mass of BaCl₂ needs to be determined.

Concept Introduction: The sum of total mass in grams in grams of all the atoms. Molar mass measured in grams/mole.

Answer to Problem 2RQ

  ${\text{Molar mass of BaCl}}_{\text{2}}\text{=208}\text{.32 g/mol}$

Explanation of Solution

  $\begin{array}{c}{\text{M}}_{{\text{BaCl}}_{\text{2}}}={\text{A}}_{\text{Ba}}{\text{+2×A}}_{\text{Cl}}\end{array}$

      $\begin{array}{c}=137.32+2\times 35.5\end{array}$

      $\begin{array}{c}=208.32\text{ g/mol}\end{array}$

(b)

Interpretation Introduction

Interpretation: The molar mass of CO₂ needs to be determined.

Concept Introduction: The sum of total mass in grams in grams of all the atoms. Molar mass measured in grams/mole.

Answer to Problem 2RQ

  ${\text{Molar mass of CO}}_{\text{2}}\text{=44g/mol}$

Explanation of Solution

  $\begin{array}{c}{\text{M}}_{{\text{CO}}_{\text{2}}}={\text{A}}_{\text{Carbon}}{\text{+2×A}}_{\text{Oxygen}}\end{array}$

      $\begin{array}{c}=12+2\times 16\end{array}$

      $\begin{array}{c}=\text{44 g/mol}\end{array}$

(c)

Interpretation Introduction

Interpretation: The molar mass of HNO₃ needs to be determined.

Concept Introduction: The sum of total mass in grams in grams of all the atoms. Molar mass measured in grams/mole.

Answer to Problem 2RQ

  ${\text{Molar mass of HNO}}_{\text{3}}\text{=63g/mol}$

Explanation of Solution

  $\begin{array}{c}{\text{M}}_{{\text{HNO}}_{\text{3}}}{\text{=A}}_{\text{Hydrogen}}{\text{+A}}_{\text{Nitrogen}}{\text{+3×A}}_{\text{Oxygen}}\end{array}$

      $\begin{array}{c}=1+14+3\times 16\end{array}$

      $\begin{array}{c}=63\text{ g/mol}\end{array}$

(d)

Interpretation Introduction

Interpretation: The molar mass of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{SO}}_{\text{4}}$ needs to be determined.

Concept Introduction: The sum of total mass in grams in grams of all the atoms. Molar mass measured in grams/mole.

Answer to Problem 2RQ

  $\text{Molar mass of}{\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{SO}}_{\text{4}}\text{=132g/mol}$

Explanation of Solution

  ${\text{M}}_{{\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{SO}}_{\text{4}}}\text{=2×}\left({\text{A}}_{\text{Nitrogen}}{\text{+4×A}}_{\text{Hydrogen}}\right){\text{+A}}_{\text{Sulphur}}{\text{+4×A}}_{\text{Oxygen}}$

Thus,

  $\begin{array}{c}\text{molar mass}=2\times \left(14+4\times 1\right)+32+4\times 16\end{array}$

        $\begin{array}{c}=2\times \left(18\right)+96\end{array}$

        $\begin{array}{c}=36+96\end{array}$

        $\begin{array}{c}=132\text{ g/mol}\end{array}$