Chapter 6, Problem 14A

Interpretation Introduction

Interpretation: Whether mass of 0.50 mol oxygen atom is more or 4 mol of hydrogen atom needs to be determined.

Concept Introduction: The molecular mass of compound is the sum of atomic mass of all the atoms present in the given chemical compound. Mole concept is used to calculate the moles, mass, number of atoms and moles of a compound. The relation between these values can be shown as:

  $\begin{array}{l}\text{Moles = }\frac{\text{mass}}{\text{molar mass}}\\ {\text{1 mole = N}}_{\text{a}}\text{ atoms}\\ {\text{N}}_{\text{a}}\text{ = 6}\text{.022 }\times {\text{ 10}}^{\text{23}}\end{array}$

Answer to Problem 14A

0.5 moles of O weighs more than 4 moles of H atoms.

Explanation of Solution

Given information:

Moles of O atoms = 0.50 moles

Moles of H atoms = 4 moles

Molar mass of O = 16.0 g/mol

Molar mass of H = 1.001 g/mol

Calculate mass of O and H atoms-

  $\begin{array}{l}\text{Mass = Moles}\times \text{molar mass}\\ \text{Mass = 0}\text{.5 moles }\times \text{ 16}\text{.0 g/mol}\\ \text{Mass = 8}\text{.0 g O atoms}\\ \text{Mass = Moles}\times \text{molar mass}\\ \text{Mass = 4 moles }\times \text{ 1}\text{.001 g/mol}\\ \text{Mass = 4}\text{.004 g H atoms}\end{array}$

Thus 0.5 moles of O weighs more than 4 moles of H atoms.

Conclusion

Mass of atoms depends on the molar mass of atoms.