Chapter 15, Problem 117A

a.

Interpretation Introduction

Interpretation:

The molar mass of cobalt nitrate needs to be determined.

Concept introduction:

The molar mass of a compound is equal to the sum of molar mass of its constituent atoms.

Answer to Problem 117A

The mass of cobalt nitrate is 290.93g/mol

Explanation of Solution

$\begin{array}{l}\begin{array}{l}Massof{\text{ Co(NO}}_3{)}_2=182.93g/mol\hfill \\ Massof{\text{ H}}_{2}O=6\left(16+2\right)=108g/mol\hfill \end{array}\\ Totalmass=183.93+108=290.93g/mol\end{array}$

b.

Interpretation Introduction

Interpretation:

The molar mass of ferric hydroxide needs to be determined.

Concept introduction:

The molar mass of a compound is equal to the sum of molar mass of its constituent atoms.

Answer to Problem 117A

The mass of ferric hydroxide is 106g/mol

Explanation of Solution

$\begin{array}{l}\begin{array}{l}Massof\text{ Fe}=55g/mol\hfill \\ MassofO=16g/mol\hfill \end{array}\\ MassofH=1g/mol\\ Totalmass=55+3(16+1)=106g/mol\end{array}$