Chapter 7, Problem 17CR

Interpretation Introduction

(a)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{Na}}_2{\text{SO}}_{4(aq)}{\text{ + BaCl}}_{2(aq)}\to {\text{ BaSO}}_{4(s)}{\text{ + 2 NaCl}}_{(aq)}$.

Explanation of Solution

The given reaction is as follows:

${\text{Na}}_2{\text{SO}}_{4(aq)}{\text{ + BaCl}}_{2(aq)}\to {\text{ BaSO}}_{4(s)}{\text{ + NaCl}}_{(aq)}$

In this unbalanced equation number of Na atoms in reactants side is two and only one in the product side. Give coefficient 2 to NaCl. Then number of Cl atoms in products side becomes two, and there are two atoms in reactants side also. Other atoms present in the equation are already balanced. So, the balanced equation will be as follows:

${\text{Na}}_2{\text{SO}}_{4(aq)}{\text{ + BaCl}}_{2(aq)}\to {\text{ BaSO}}_{4(s)}{\text{ + 2 NaCl}}_{(aq)}$.

Interpretation Introduction

(b)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{Zn}}_{(s)}{\text{ + H}}_2{\text{O}}_{(g)}\to {\text{ ZnO}}_{(s)}{\text{ + H}}_2{}_{(g)}$.

Explanation of Solution

The equation is already balanced. Number of Zn atoms, H atoms and O atoms are same on both sides of the reaction arrow that is reactant and product sides.

Interpretation Introduction

(c)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{3 NaOH}}_{(aq)}{\text{ + H}}_3{\text{PO}}_4{}_{(aq)}\to {\text{ Na}}_3{\text{PO}}_4{}_{(aq)}{\text{ + 3 H}}_2{\text{O}}_{(l)}$.

Explanation of Solution

${\text{NaOH}}_{(aq)}{\text{ + H}}_3{\text{PO}}_4{}_{(aq)}\to {\text{ Na}}_3{\text{PO}}_4{}_{(aq)}{\text{ + H}}_2{\text{O}}_{(l)}$

In the unbalanced equation, number of Na atoms in reactants side is one and in products side its three. So, give coefficient 3 to NaOH. The number of H atoms in the reactants side becomes six. Give coefficient 3 to H₂ O to balance the number of H atoms. Thus, the balanced chemical reaction will be:

${\text{3 NaOH}}_{(aq)}{\text{ + H}}_3{\text{PO}}_4{}_{(aq)}\to {\text{ Na}}_3{\text{PO}}_4{}_{(aq)}{\text{ + 3 H}}_2{\text{O}}_{(l)}$.

Interpretation Introduction

(d)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{2 Al}}_{(s)}{\text{ + Mn}}_2{\text{O}}_3{}_{(s)}\to {\text{ Al}}_2{\text{O}}_3{}_{(s)}{\text{ + 2 Mn}}_{(s)}$.

Explanation of Solution

${\text{Al}}_{(s)}{\text{ + Mn}}_2{\text{O}}_3{}_{(s)}\to {\text{ Al}}_2{\text{O}}_3{}_{(s)}{\text{ + Mn}}_{(s)}$

In the unbalanced equation, number of aluminum in reactants side is one but two in products side thus, give coefficient 2 to Al. Now, number of Mn in reactants side is two, but one in products side. Give coefficient 2 to Mn to balance the number of Mn atoms. The number of O is already balanced. Thus, the balanced equation is,

${\text{2 Al}}_{(s)}{\text{ + Mn}}_2{\text{O}}_3{}_{(s)}\to {\text{ Al}}_2{\text{O}}_3{}_{(s)}{\text{ + 2 Mn}}_{(s)}$.

Interpretation Introduction

(e)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{2 C}}_7{\text{H}}_6{\text{O}}_2{}_{(s)}{\text{ + 15 O}}_2{}_{(g)}\to {\text{ 14 CO}}_2{}_{(g)}{\text{ + 6 H}}_2{\text{O}}_{(g)}$.

Explanation of Solution

${\text{C}}_7{\text{H}}_6{\text{O}}_2{}_{(s)}{\text{ + O}}_2{}_{(g)}\to {\text{ CO}}_2{}_{(g)}{\text{ + H}}_2{\text{O}}_{(g)}$

In the unbalanced equation, number of C in reactants side is seven but one in products side. Give coefficient 7 to CO₂. Number of H atoms in reactants side is six, but only two in the products side thus, give coefficient 3 to H₂ O. The number of O atoms in the products side becomes 17, but there are only four in the reactants side thus, give coefficient 15/2 to before O₂. But one cannot keep fractions as a coefficient in a balanced equation thus, multiply the whole equation by two so that the denominator of 15/2 is cancelled off. Thus, the balanced equation will be:

${\text{2 C}}_7{\text{H}}_6{\text{O}}_2{}_{(s)}{\text{ + 15 O}}_2{}_{(g)}\to {\text{ 14 CO}}_2{}_{(g)}{\text{ + 6 H}}_2{\text{O}}_{(g)}$.

Interpretation Introduction

(f)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{2 C}}_6{\text{H}}_{14}{}_{(l)}{\text{ + 19 O}}_2{}_{(g)}\to {\text{ 12 CO}}_2{}_{(g)}{\text{ + 14 H}}_2{\text{O}}_{(g)}$.

Explanation of Solution

${\text{C}}_6{\text{H}}_{14}{}_{(l)}{\text{ + O}}_2{}_{(g)}\to {\text{ CO}}_2{}_{(g)}{\text{ + H}}_2{\text{O}}_{(g)}$

In the unbalanced equation, number of C in reactants side is six but one in products side. Give coefficient 6 to CO₂. Number of H atoms in reactants side is 14, but only 2 atoms in the products side. Thus, give coefficient 7 to H₂ O, the number of O in the products side becomes 19, but there are only two in the reactants side. Give coefficient 19/2 to O₂. But one cannot keep fractions as a coefficient in a balanced equation. Therefore, multiply the whole equation by 2 so that the denominator of 19/2 is cancelled off. So, the balanced equation is,

${\text{2 C}}_6{\text{H}}_{14}{}_{(l)}{\text{ + 19 O}}_2{}_{(g)}\to {\text{ 12 CO}}_2{}_{(g)}{\text{ + 14 H}}_2{\text{O}}_{(g)}$.

Interpretation Introduction

(g)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{2 C}}_3{\text{H}}_8{\text{O}}_{(l)}{\text{ + 9 O}}_2{}_{(g)}\to {\text{ 6 CO}}_2{}_{(g)}{\text{ + 8 H}}_2{\text{O}}_{(g)}$.

Explanation of Solution

${\text{C}}_3{\text{H}}_8{\text{O}}_{(l)}{\text{ + O}}_2{}_{(g)}\to {\text{ CO}}_2{}_{(g)}{\text{ + H}}_2{\text{O}}_{(g)}$

In the unbalanced equation, number of C in reactants side is three but one in products side. Give coefficient 3 to CO₂. Number of H atoms in reactants side is fourteen, but only two in the products side. Thus, give coefficient 4 to H₂ O. But then the number of O atoms in the products side becomes 10, but there are only 3 atoms in the reactants side. Thus, give coefficient 9/2 to O₂. But one cannot keep fractions as a coefficient in a balanced equation. Therefore, one multiply the whole equation by 2 so that the denominator of 9/2 is cancelled off. Thus, the balanced equation is,

${\text{2 C}}_3{\text{H}}_8{\text{O}}_{(l)}{\text{ + 9 O}}_2{}_{(g)}\to {\text{ 6 CO}}_2{}_{(g)}{\text{ + 8 H}}_2{\text{O}}_{(g)}$.

Interpretation Introduction

(h)

Interpretation:

Given chemical equation should be balanced.

Concept Introduction:

Balanced chemical equation gives the details about the identities of the reactants and products and also how much of each reactant and product participate in the reaction. The numbers in the balanced equation (coefficients) enable us to determine how much product we can get from a given quantity of reactants.

Normally the unbalanced equations are balanced by inspection starting with the most complicated molecule. We should determine what coefficient is necessary to equalize the number of each type of atoms on both side of the arrow. The coefficients used should be the smallest integers which balance the equation.

Answer to Problem 17CR

${\text{Mg}}_{(s)}{\text{ + 2 HClO}}_4{}_{(aq)}\to {\text{ Mg(ClO}}_4{)}_2{}_{(aq)}{\text{ + H}}_2{}_{(g)}$.

Explanation of Solution

${\text{Mg}}_{(s)}{\text{ + HClO}}_4{}_{(aq)}\to {\text{ Mg(ClO}}_4{)}_2{}_{(aq)}{\text{ + H}}_2{}_{(g)}$

In the unbalanced equation, number of H atoms in the reactants side is 1 but in the products side, it is 2. Thus, give coefficient 2 to HClO₄. Then all the other atoms get balanced. Mg is already balanced. Thus, the balanced equation will be:

${\text{Mg}}_{(s)}{\text{ + 2 HClO}}_4{}_{(aq)}\to {\text{ Mg(ClO}}_4{)}_2{}_{(aq)}{\text{ + H}}_2{}_{(g)}$.