Chapter 10.2, Problem 16PP

(a)

Interpretation Introduction

Interpretation:

The $\text{3}\text{.45}\times {\text{10}}^{\text{2 }}$ moles of Co need to be converted to mass in grams expressed in scientific notation.

Concept introduction:

The mole concept provides the relation between moles, mass and molar mass. The mathematical expression of mole concept can be written as:

$\text{Mole =}\frac{\text{Mass}}{\text{Molar mass}}$

Answer to Problem 16PP

$\text{Mass = 2}{\text{.03×10}}^{\text{4 }}\text{g}$

Explanation of Solution

Given Information:

Moles of Co = $\text{3}\text{.45}\times {\text{10}}^{\text{2 }}$ moles

Molar mass of Co = 58.9 g/mol

Calculation:

Substitute the values to calculate mass:

$\begin{array}{l}\text{Mole =}\frac{\text{Mass}}{\text{Molar mass}}\\ \text{3}{\text{.45×10}}^{\text{2 }}\text{moles=}\frac{\text{Mass}}{\text{58}\text{.9 g/mol }}\\ \text{Mass = 3}{\text{.45×10}}^{\text{2 }}\text{moles×58}\text{.9 g/mol}\\ \text{Mass = 2}{\text{.03×10}}^{\text{4 }}\text{g}\end{array}$

(b)

Interpretation Introduction

Interpretation:

$\text{2}\text{.45}\times {\text{10}}^{\text{-2 }}$ moles of Zn needs to be converted to mass in grams expressed in scientific notation.

Concept introduction:

The mole concept provides the relation between moles, mass and molar mass. The mathematical expression of mole concept can be written as:

$\text{Mole =}\frac{\text{Mass}}{\text{Molar mass}}$

Answer to Problem 16PP

$\text{Mass =1}\text{.60 g}$

Explanation of Solution

Given Information:

Moles of Zn = $\text{2}\text{.45}\times {\text{10}}^{\text{-2 }}$ moles

Molar mass of Zn = 65.4 g/mol

Calculation:

Substitute the values to calculate mass:

$\begin{array}{l}\text{Mole =}\frac{\text{Mass}}{\text{Molar mass}}\\ \text{2}\text{.45}\times {\text{10}}^{\text{-2 }}\text{moles=}\frac{\text{Mass}}{\text{65}\text{.4 g/mol }}\\ \text{Mass = 2}\text{.45}\times {\text{10}}^{\text{-2 }}\text{moles× 65}\text{.4 g/mol}\\ \text{Mass =1}\text{.60 g}\end{array}$