Chapter 6, Problem 19A

(a)

Interpretation Introduction

Interpretation: The molar mass of sodium nitride ${\text{Na}}_{\text{3}}\text{N}$ 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 molar mass of any compound can be calculated with the help of atomic masses of component atoms.

Answer to Problem 19A

Molar mass = 83.0 u

Explanation of Solution

Atomic mass of Na = 23.0 u

Atomic mass of N = 14.0 u

Molar mass of ${\text{Na}}_{\text{3}}\text{N}$ = $\text{( 23}\text{.0}\times \text{ 3)+(14}\text{.0) = 83}\text{.0 u}$

(b)

Interpretation Introduction

Interpretation: The molar mass of carbon disulfide ${\text{CS}}_{\text{2}}$ 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 molar mass of any compound can be calculated with the help of atomic masses of component atoms.

Answer to Problem 19A

Molar mass = 76.0 u

Explanation of Solution

Atomic mass of C = 12.0 u

Atomic mass of S = 32.0 u

Molar mass of ${\text{CS}}_{\text{2}}$ = $\text{( 12}\text{.0}\times \text{ 1)+(32}\text{.0}\times \text{2) = 76}\text{.0 u}$

(c)

Interpretation Introduction

Interpretation: The molar mass of ammonium bromide ${\text{NH}}_{\text{4}}\text{Br}$ 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 molar mass of any compound can be calculated with the help of atomic masses of component atoms.

Answer to Problem 19A

Molar mass = 97.9 u

Explanation of Solution

Atomic mass of N = 14.0 u

Atomic mass of H = 1.001 u

Atomic mass of Br = 79.9 u

Molar mass of ${\text{NH}}_{\text{4}}\text{Br}$ = $\text{( 14}\text{.0}\times \text{ 1)+(1}\text{.001}\times \text{4)+(79}\text{.9}\times \text{1) = 97}\text{.9 u}$

(d)

Interpretation Introduction

Interpretation: The molar mass of ethyl alcohol ${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}$ 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 molar mass of any compound can be calculated with the help of atomic masses of component atoms.

Answer to Problem 19A

Molar mass = 44.0 u

Explanation of Solution

Atomic mass of C = 12.0 u

Atomic mass of H = 1.001 u

Atomic mass of O = 16.0 u

Molar mass of ${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{OH}$ = $\text{( 12}\text{.0}\times \text{ 2)+(1}\text{.001}\times \text{6)+(16}\text{.0}\times \text{1) = 44}\text{.0 u}$

(e)

Interpretation Introduction

Interpretation: The molar mass of sulphurous acid ${\text{H}}_{\text{2}}{\text{SO}}_{\text{3}}$ 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 molar mass of any compound can be calculated with the help of atomic masses of component atoms.

Answer to Problem 19A

Molar mass = 66.0 u

Explanation of Solution

Atomic mass of S = 32.0 u

Atomic mass of H = 1.001 u

Atomic mass of O = 16.0 u

Molar mass of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{3}}$ = $\text{( 16}\text{.0}\times \text{ 1)+(1}\text{.001}\times \text{2)+(16}\text{.0}\times \text{3) = 66}\text{.0 u}$

(f)

Interpretation Introduction

Interpretation: The molar mass of sulphuric acid ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ 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 molar mass of any compound can be calculated with the help of atomic masses of component atoms.

Answer to Problem 19A

Molar mass = 82.0 u

Explanation of Solution

Atomic mass of S = 32.0 u

Atomic mass of H = 1.001 u

Atomic mass of O = 16.0 u

Molar mass of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ = $\text{( 16}\text{.0}\times \text{ 1)+(1}\text{.001}\times \text{2)+(16}\text{.0}\times \text{4) = 82}\text{.0 u}$