Chapter 7, Problem 28PE

(a)

Interpretation Introduction

Interpretation:

The percent composition of the compound ${\text{ZnCl}}_{\text{2}}$ has to be given.

Answer to Problem 28PE

The percent composition of Zinc is $\text{47}\text{.98\%}\text{.}$

The percent composition of chlorine is $\text{52}\text{.02\%}\text{.}$

Explanation of Solution

Given,

The atomic mass of Zinc atom $\text{=65}\text{.39}\text{g}$

The atomic mass of chlorine atom $\text{=35}\text{.45}\text{g}$

The molecular weight of ${\text{ZnCl}}_{\text{2}}$$\text{=63}\text{.39}\text{g+70}\text{.90}\text{g=136}\text{.3g}$

The percent composition for each element can be calculated as,

The percent composition of Zinc $\text{=}\left(\frac{65.39\text{g}}{\text{136}\text{.3}\text{g}}\right)\text{×100=47}\text{.98\%}$

The percent composition of Zinc is $\text{47}\text{.98\%}\text{.}$

The percent composition of chlorine $\text{=}\left(\frac{70.90g}{136.3g}\right)\text{×100=52}\text{.02\%}$

The percent composition of chlorine is $\text{52}\text{.02\%}\text{.}$

(b)

Interpretation Introduction

Interpretation:

The percent composition of the compound ${\text{NH}}_{\text{4}}{\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}$  has to be given.

Answer to Problem 28PE

The percent composition of Nitrogen is $\text{18}\text{.17\%}\text{.}$

The percent composition of Hydrogen is $\text{9}\text{.153\%}\text{.}$

The percent composition of Carbon is $\text{31}\text{.16\%}\text{.}$

The percent composition of Oxygen is $\text{41}\text{.51\%}\text{.}$

Explanation of Solution

Given,

The atomic mass of nitrogen atom $\text{=14}\text{.01}\text{g}$

The atomic mass of hydrogen atom $\text{=1}\text{.008}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The atomic mass of carbon atom $\text{=12}\text{.01}\text{g}$

The molecular weight of ${\text{NH}}_{\text{4}}{\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}$$\text{=14}\text{.01}\text{g+7}\text{.056}\text{g+24}\text{.02+32}\text{g=77}\text{.09}\text{g}$

The percent composition for each element can be calculated as,

The percent composition of Nitrogen $\text{=}\left(\frac{14.01\text{g}}{77.09\text{g}}\right)\text{×100=18}\text{.17\%}$

The percent composition of Nitrogen is $\text{18}\text{.17\%}\text{.}$

The percent composition of Hydrogen $\text{=}\left(\frac{7.056\text{g}}{77.09\text{g}}\right)\text{×100=9}\text{.153\%}$

The percent composition of Hydrogen is $\text{9}\text{.153\%}\text{.}$

The percent composition of Carbon $\text{=}\left(\frac{24.02\text{g}}{77.09\text{g}}\right)\text{×100=31}\text{.16\%}$

The percent composition of Carbon is $\text{31}\text{.16\%}\text{.}$

The percent composition of Oxygen $\text{=}\left(\frac{32\text{g}}{77.09\text{g}}\right)\text{×100=41}\text{.51\%}$

The percent composition of Oxygen is $\text{41}\text{.51\%}\text{.}$

(c)

Interpretation Introduction

Interpretation:

The percent composition of the compound ${\text{MgP}}_{\text{2}}{\text{O}}_{\text{7}}$ has to be given.

Answer to Problem 28PE

The percent composition of magnesium is $\text{12}\text{.26\%}\text{.}$

The percent composition of phosphorus is $\text{31}\text{.24\%}\text{.}$

The percent composition of Oxygen is $\text{56}\text{.48\%}\text{.}$

Explanation of Solution

Given,

The atomic mass of magnesium atom $\text{=24}\text{.31}\text{g}$

The atomic mass of phosphorus atom $\text{=30}\text{.97}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular weight of ${\text{MgP}}_{\text{2}}{\text{O}}_{\text{7}}$$\text{=24}\text{.31}\text{g+61}\text{.94}\text{g+112}\text{.0}\text{g=198}\text{.3}\text{g}$

The percent composition for each element can be calculated as,

The percent composition of magnesium $\text{=}\left(\frac{24.31\text{g}}{\text{198}\text{.3}\text{g}}\right)\text{×100=12}\text{.26\%}$

The percent composition of magnesium is $\text{12}\text{.26\%}\text{.}$

The percent composition of phosphorus $\text{=}\left(\frac{61.94\text{g}}{\text{198}\text{.3}\text{g}}\right)\text{×100=31}\text{.24\%}$

The percent composition of phosphorus is $\text{31}\text{.24\%}\text{.}$

The percent composition of Oxygen $\text{=}\left(\frac{112\text{g}}{\text{198}\text{.3}\text{g}}\right)\text{×100=56}\text{.48\%}$

The percent composition of Oxygen is $\text{56}\text{.48\%}\text{.}$

(d)

Interpretation Introduction

Interpretation:

The percent composition of the compound ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{SO}}_{\text{4}}$ has to be given.

Answer to Problem 28PE

The percent composition of Nitrogen is $\text{21}\text{.20\%}\text{.}$

The percent composition of Hydrogen is $\text{6}\text{.100\%}\text{.}$

The percent composition of Sulfur is $\text{24}\text{.26\%}\text{.}$

The percent composition of Oxygen is $\text{48}\text{.41\%}\text{.}$

Explanation of Solution

Given,

The atomic mass of nitrogen atom $\text{=14}\text{.01}\text{g}$

The atomic mass of hydrogen atom $\text{=1}\text{.008}\text{g}$

The atomic mass of sulfur atom $\text{=32}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular weight of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{SO}}_{\text{4}}$$\text{=28}\text{.09}\text{g+8}\text{.064}\text{g+32}\text{g+64}\text{g=132}\text{.2}\text{g}$

The percent composition for each element can be calculated as,

The percent composition of Nitrogen $\text{=}\left(\frac{28.09\text{g}}{132.2\text{g}}\right)\text{×100=21}\text{.20\%}$

The percent composition of Nitrogen is $\text{21}\text{.20\%}\text{.}$

The percent composition of Hydrogen $\text{=}\left(\frac{8.064\text{g}}{132.2\text{g}}\right)\text{×100=6}\text{.100\%}$

The percent composition of Hydrogen is $\text{6}\text{.100\%}\text{.}$

The percent composition of Sulfur $\text{=}\left(\frac{32.07\text{g}}{132.2\text{g}}\right)\text{×100=24}\text{.26\%}$

The percent composition of Sulfur is $\text{24}\text{.26\%}\text{.}$

The percent composition of Oxygen $\text{=}\left(\frac{64\text{g}}{132.2\text{g}}\right)\text{×100=48}\text{.41\%}$

The percent composition of Oxygen is $\text{48}\text{.41\%}\text{.}$

(e)

Interpretation Introduction

Interpretation:

The percent composition of the compound $\text{Fe}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}$ has to be given.

Answer to Problem 28PE

The percent composition of iron is $\text{23}\text{.09\%}\text{.}$

The percent composition of nitrogen is $\text{17}\text{.37\%}\text{.}$

The percent composition of oxygen is $\text{59}\text{.53\%}\text{.}$

Explanation of Solution

Given,

The atomic mass of iron atom $\text{=55}\text{.85}\text{g}$

The atomic mass of nitrogen atom $\text{=14}\text{.01}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular weight of $\text{Fe}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}$$\text{=55}\text{.85}\text{g+42}\text{.03}\text{g+144}\text{g=241}\text{.9}\text{g}$

The percent composition for each element can be calculated as,

The percent composition of iron $\text{=}\left(\frac{55.85\text{g}}{241.9\text{g}}\right)\text{×100=23}\text{.09\%}$

The percent composition of iron is $\text{23}\text{.09\%}\text{.}$

The percent composition of nitrogen $\text{=}\left(\frac{42.03\text{g}}{241.9\text{g}}\right)\text{×100=17}\text{.37\%}$

The percent composition of nitrogen is $\text{17}\text{.37\%}\text{.}$

The percent composition of oxygen $\text{=}\left(\frac{144\text{g}}{241.9\text{g}}\right)\text{×100=59}\text{.53\%}$

The percent composition of oxygen is $\text{59}\text{.53\%}\text{.}$

(f)

Interpretation Introduction

Interpretation:

The percent composition of the compound ${\text{ICl}}_{\text{3}}$ has to be given.

Answer to Problem 28PE

The percent composition of Iodine is $\text{54}\text{.39\%}\text{.}$

The percent composition of Chlorine is $\text{45}\text{.61\%}\text{.}$

Explanation of Solution

Given,

The atomic mass of $\text{I}$ atom $\text{=126}\text{.9}\text{g}$

The atomic mass of chlorine atom $\text{=35}\text{.45}\text{g}$

The molecular weight of ${\text{ICl}}_{\text{3}}$$\text{=126}\text{.9}\text{g+106}\text{.4}\text{g=233}\text{.3}\text{g}$

The percent composition for each element can be calculated as,

The percent composition of Iodine $\text{=}\left(\frac{126.9\text{g}}{233.3\text{g}}\right)\text{×100=54}\text{.39\%}$

The percent composition of Iodine is $\text{54}\text{.39\%}\text{.}$

The percent composition of Chlorine $\text{=}\left(\frac{106.4\text{g}}{233.3\text{g}}\right)\text{×100=45}\text{.61\%}$

The percent composition of Chlorine is $\text{45}\text{.61\%}\text{.}$