Chapter 8.2, Problem 18PP

Interpretation Introduction

(a)

Interpretation:

The number of moles of Zn needs to be determined.

Concept introduction:

For the given name of an element, the number of moles is equal to the ratio of the given weight upon the gram molecular weight of the element i.e. $n=\frac{W}{M}$

Answer to Problem 18PP

The moles of $1\cdot 25\times {10}^3\text{ g}$ of Zn is $=1\cdot 912\times {10}^{+1}$

Explanation of Solution

Given information:

Weight of Zn is $=1\cdot 25\times {10}^3\text{ g}$

Formula used:

$n=\frac{W}{M}$

Where n = number of moles

W = weight

M = gram molecules weight

Calculation:

Given weight $=1\cdot 25\times {10}^3\text{ g}$

$\text{number of moles = }\frac{\text{weight }\left(gram\right)}{\text{gram molecular weight}}$

Gram molecular weight of Zn is $=65\cdot 37$

$n=\frac{W}{M}=\frac{1\cdot 25\times {10}^3\text{ g}}{65\cdot 37\text{ g/mol}}=1\cdot 9122\times {10}^1\text{ mol}$

b.

Interpretation Introduction

Interpretation:

The number of moles of Fe needs to be calculated.

Concept introduction:

For the given name of an element the number of moles is equal to the ratio of the given weight upon the gram molecular weight of the element i.e. $n=\frac{W}{M}$

Answer to Problem 18PP

The moles of $1\text{ Kg}$ of Fe is $=1\cdot 7906\times {10}^{+1}$

Explanation of Solution

Given information:

Weight of Iron is $=1000\text{ g}$

Formula used:

$n=\frac{W}{M}$

Where n = number of moles

W = weight

M = gram molecules weight

Calculation:

Given weight $=1000\text{ g}$

$\begin{array}{l}\text{number of moles = }\frac{W}{M}=\frac{1000}{55\cdot 847}=17\cdot 906\\ =1\cdot 7906\times {10}^1\end{array}$