Chapter U4.9, Problem 5E

(a)

Interpretation Introduction

Interpretation:

The element from carbon and hydrogen that has more mass is to be determined.

Concept Introduction :

The number of moles is defined as the ratio of the weight of the substance to its molar mass. Molar mass is defined as the sum of the average atomic masses of all the atoms present in the chemical formula of any compound.

The formula to calculate number of moles is shown below.

  $\text{Number of moles }=\frac{\text{Mass}}{\text{Molar mass}}$ . (1)

Answer to Problem 5E

One mole of carbon has more mass than one mole of hydrogen.

Explanation of Solution

The molar mass of hydrogen is $\text{1}\text{.00784 g/mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{1}\text{.00784 g/mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{1}\text{.00784}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=1.00784\text{g}\end{array}$

The molar mass of carbon is $\text{12}\text{.0107 g/mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{12}\text{.0107 g/mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{12}\text{.0107}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=\text{12}\text{.0107 g}\end{array}$

The calculated mass value of carbon is greater than hydrogen. Therefore, one mole of carbon has more mass than one mole of hydrogen.

(b)

Interpretation Introduction

Interpretation:

The element from iron and aluminium that has more mass is to be determined.

Concept Introduction :

The number of moles is defined as the ratio of the weight of the substance to its molar mass. Molar mass is defined as the sum of the average atomic masses of all the atoms present in the chemical formula of any compound.

The formula to calculate number of moles is shown below.

  $\text{Number of moles }=\frac{\text{Mass}}{\text{Molar mass}}$ . (1)

Answer to Problem 5E

One mole of iron has more mass than one mole of aluminum.

Explanation of Solution

The molar mass of aluminum is $\text{26}\text{.98 g}/\text{mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{26}\text{.98 g}/\text{mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{26}\text{.98}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=\text{26}\text{.98 g}\end{array}$

The molar mass of iron is $\text{55}\text{.845 g}/\text{mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{55}\text{.845 g}/\text{mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{55}\text{.845}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=\text{55}\text{.845 g}\end{array}$

The calculated mass value of iron is greater than aluminum. Therefore, one mole of iron has more mass than one mole of aluminum.

(c)

Interpretation Introduction

Interpretation:

The element from gold and copper that has more mass is to be determined.

Concept Introduction :

The number of moles is defined as the ratio of the weight of the substance to its molar mass. Molar mass is defined as the sum of the average atomic masses of all the atoms present in the chemical formula of any compound.

The formula to calculate number of moles is shown below.

  $\text{Number of moles }=\frac{\text{Mass}}{\text{Molar mass}}$ . (1)

Answer to Problem 5E

One mole of gold has more mass than one mole of copper.

Explanation of Solution

The molar mass of copper is $\text{63}\text{.546 g}/\text{mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{63}\text{.546 g}/\text{mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{63}\text{.546}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=\text{63}\text{.546 g}\end{array}$

The molar mass of gold is $\text{196}\text{.966 g}/\text{mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{196}\text{.966 g}/\text{mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{196}\text{.966}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=\text{196}\text{.966 g}\end{array}$

The calculated mass value of gold is greater than copper. Therefore, one mole of gold has more mass than one mole of copper.

(d)

Interpretation Introduction

Interpretation:

The element from gold and carbon that has more mass is to be determined.

Concept Introduction :

The number of moles is defined as the ratio of the weight of the substance to its molar mass. Molar mass is defined as the sum of the average atomic masses of all the atoms present in the chemical formula of any compound.

The formula to calculate number of moles is shown below.

  $\text{Number of moles }=\frac{\text{Mass}}{\text{Molar mass}}$ . (1)

Answer to Problem 5E

One mole of gold has more mass than five moles of carbon.

Explanation of Solution

The molar mass of carbon is $\text{12}\text{.0107 g/mol}$ .

Substitute given mole as $5\text{mol}$ and molar mass as $\text{12}\text{.0107 g/mol}$ in equation (1).

  $\begin{array}{c}5\text{mol }=\frac{\text{Mass}}{\text{12}\text{.0107}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=60.0535\text{ g}\end{array}$

The molar mass of gold is $\text{196}\text{.966 g}/\text{mol}$ .

Substitute given mole as $\text{1}\text{mol}$ and molar mass as $\text{196}\text{.966 g}/\text{mol}$ in equation (1).

  $\begin{array}{c}\text{1}\text{mol }=\frac{\text{Mass}}{\text{196}\text{.966}\frac{\text{g}}{\text{mol}}}\\ \text{Mass}=\text{196}\text{.966 g}\end{array}$

The calculated mass value of gold is greater than carbon. Therefore, one mole of gold has more mass than five moles of carbon.