Chapter 9, Problem 4A

(a)

Interpretation Introduction

Interpretation:

For the given balanced equation, the meaning of the equation in terms of the numbers of individual molecules and in terms of moles of molecules needs to be stated.

  ${\mathrm{PCl}}_3\left(l\right)+H_{2}O\left(l\right)\to H_{3}P{O}_3\left(aq\right)+HCl\left(g\right)$

Concept Introduction:

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

Answer to Problem 4A

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}\text{a}{\text{. 2 PCl}}_{\text{3}}\left(\text{l}\right){\text{ + 6H}}_{\text{2}}\text{O }\left(\text{l}\right)\to {\text{2 H}}_{\text{3}}{\text{PO}}_{\text{3}}\left(\text{aq}\right)\text{ + 6 HCl}\left(\text{g}\right)\hfill \\ \text{2molecules 6molecules 2molecules 6molecules }\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{2 moles 6 mol}\text{ 2 moles}\text{ 6 moles }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

Explanation of Solution

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}\text{a}{\text{. 2 PCl}}_{\text{3}}\left(\text{l}\right){\text{ + 6H}}_{\text{2}}\text{O }\left(\text{l}\right)\to {\text{2 H}}_{\text{3}}{\text{PO}}_{\text{3}}\left(\text{aq}\right)\text{ + 6 HCl}\left(\text{g}\right)\hfill \\ \text{2molecules 6molecules 2molecules 6molecules }\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{2 moles 6 mol}\text{ 2 moles}\text{ 6 moles }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

This means:

2 molecules of PCl₃ react with 6 molecules of water and 2 molecules of H₃PO₄ and 6 molecules of HCl are formed.

2 moles of PCl₃ molecules react with 6 moles of water molecules and form 2 moles of H₃PO₃ molecules and 6 moles of HCl molecules.

(b)

Interpretation Introduction

Interpretation:

For the given balanced equation, the meaning of the equation in terms of the numbers of individual molecules and in terms of moles of molecules needs to be stated.

  ${\text{XeF}}_{\text{2}}\left(\text{g}\right){\text{ + H}}_{\text{2}}\text{O }\left(\text{l}\right)\to \text{Xe }\left(\text{g}\right)\text{ + HF }\left(\text{g}\right){\text{ + O}}_{\text{2}}\left(\text{g}\right)$

Concept Introduction:

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

Answer to Problem 4A

  $\begin{array}{l}{\text{2 XeF}}_{\text{2}}\left(\text{g}\right){\text{ + 2 H}}_{\text{2}}\text{O }\left(\text{l}\right)\to \text{ 2 Xe }\left(\text{g}\right)\text{ + 4 HF }\left(\text{g}\right){\text{ + O}}_{\text{2}}\left(\text{g}\right)\hfill \\ \text{2molecules 2molecule 2molecules 4molecules 1 molecule}\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{2 moles 2 mol}\text{ 2 moles}\text{ 4 moles 1 mole }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

Explanation of Solution

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}{\text{2 XeF}}_{\text{2}}\left(\text{g}\right){\text{ + 2 H}}_{\text{2}}\text{O }\left(\text{l}\right)\to \text{ 2 Xe }\left(\text{g}\right)\text{ + 4 HF }\left(\text{g}\right){\text{ + O}}_{\text{2}}\left(\text{g}\right)\hfill \\ \text{2molecules 2molecule 2molecules 4molecules 1 molecule}\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{2 moles 2 mol}\text{ 2 moles}\text{ 4 moles 1 mole }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

This means:

2 XeF₂ molecules react with H₂O molecules and form 2 Xe atoms, 4 HF molecules and one O₂ molecule.

2 moles of XeF₂ molecules react with 2 moles of H₂O molecules and form 2 moles of Xe atoms, 4 moles of HF molecules and one mole of O₂ molecule.

(c)

Interpretation Introduction

Interpretation:

For the given balanced equation, the meaning of the equation in terms of the numbers of individual molecules and in terms of moles of molecules needs to be stated.

  $\text{S }\left(\text{s}\right){\text{ + HNO}}_{\text{3}}\left(\text{aq}\right)\to {\text{ H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(\text{aq}\right){\text{ + H}}_{\text{2}}\text{O }\left(\text{l}\right){\text{ + NO}}_{\text{2}}\left(\text{g}\right)$

Concept Introduction:

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

Answer to Problem 4A

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}\text{S }\left(\text{s}\right){\text{ + 6 HNO}}_{\text{3}}\left(\text{aq}\right)\to {\text{ H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(\text{aq}\right){\text{ + 2 H}}_{\text{2}}\text{O }\left(\text{l}\right){\text{ + 6 NO}}_{\text{2}}\left(\text{g}\right)\hfill \\ \text{1atom 6molecules 1molecule 2molecules 6 molecules}\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{1mole 6 moles}\text{ 1 mole}\text{ 2moles 6moles }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

Explanation of Solution

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}\text{S }\left(\text{s}\right){\text{ + 6 HNO}}_{\text{3}}\left(\text{aq}\right)\to {\text{ H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(\text{aq}\right){\text{ + 2 H}}_{\text{2}}\text{O }\left(\text{l}\right){\text{ + 6 NO}}_{\text{2}}\left(\text{g}\right)\hfill \\ \text{1atom 6molecules 1molecule 2molecules 6 molecules}\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{1mole 6 moles}\text{ 1 mole}\text{ 2moles 6moles }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

This means:

1 atom of S reacts with 6 molecules of HNO₃ and a molecule of H₂SO₄, 2 molecules of H₂O and 6 molecules of NO₂ are formed.

1 mole of S atom reacts with 6 mole d molecules of HNO₃ and forms a mole of H₂SO₄ molecule, 2 moles of H₂O molecules and 6 moles of NO₂ molecules.

(d)

Interpretation Introduction

Interpretation:

For the given balanced equation, the meaning of the equation in terms of the numbers of individual molecules and in terms of moles of molecules needs to be stated.

  ${\text{NaHSO}}_{\text{3}}\left(\text{s}\right)\to {\text{ Na}}_{\text{2}}{\text{SO}}_{\text{3}}\left(\text{s}\right){\text{ + SO}}_{\text{2}}\left(\text{g}\right){\text{ + H}}_{\text{2}}\text{O }\left(\text{l}\right)$

Concept Introduction:

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

Answer to Problem 4A

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}{\text{2 NaHSO}}_{\text{3}}\left(\text{s}\right)\to {\text{ Na}}_{\text{2}}{\text{SO}}_{\text{3}}\left(\text{s}\right){\text{ + SO}}_{\text{2}}\left(\text{g}\right){\text{ + H}}_{\text{2}}\text{O }\left(\text{l}\right)\hfill \\ \text{2molecules 1molecule 1molecule 1 molecule}\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{2moles }\text{ 1 mole}\text{ 1mole 1mole }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

Explanation of Solution

The balancing process of the chemical equations consists of equalizing the atoms of the elements in the reactants and products.

The balanced equation of the chemical reaction is as follows:

  $\begin{array}{l}{\text{2 NaHSO}}_{\text{3}}\left(\text{s}\right)\to {\text{ Na}}_{\text{2}}{\text{SO}}_{\text{3}}\left(\text{s}\right){\text{ + SO}}_{\text{2}}\left(\text{g}\right){\text{ + H}}_{\text{2}}\text{O }\left(\text{l}\right)\hfill \\ \text{2molecules 1molecule 1molecule 1 molecule}\left(\text{In terms of }\text{number of individual molecules}\right)\hfill \\ \text{2moles }\text{ 1 mole}\text{ 1mole 1mole }\left(\text{In terms of moles of molecules}\right)\hfill \end{array}$

This means:

2 molecules of NaHSO₃ decompose into a molecule of Na₂SO₃, a molecule of SO₂ and a molecule of H₂O.

2 moles of NaHSO₃ molecules decompose into one mole of Na₂SO₃ molecule, one mole of SO₂ molecule and one mole of H₂O molecule.