Chapter 15, Problem 22A

Solution

(a)

Interpretation:

Molarity of CuCl₂ solution have to be calculated.

Concept Introduction:

Composition of a solution can be defined by expressing its concentration. The concentrations of solutions can be expressed in different ways, which are involved in the quantity of solute and the quantity of solution or solvent. Various methods are used to describe the concentration of the solution quantitatively. Some commonly used quantitative concentration terms are percent by mass, percent by volume, molarity, molality and mole fraction.

Molarity: Molarity is defined as the number of moles of solute present in one litre of the solution In expression, $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Again $\mathrm{Number}ofmolesofsolute=\frac{Massofthesolute}{Molecularweightofthesolute}$

Molarity of CuCl₂solution is 0.253 M.

  $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Data given: Mass of CuCl₂= 4.25 gm

Volume of CuCl₂solution = 125 mL = 0.125 L

  $\begin{array}{l}NumberofmolesofCuC{l}_2=\frac{MassofCuC{l}_2}{MolecularweightofCuC{l}_2}\\ =\frac{4.25gm}{134.45gm/mol}=0.0316mol\end{array}$

  $\begin{array}{l}MolarityofCuC{l}_{2}solution=\frac{NumberofmolesofCuC{l}_2}{ Volume of CuC{l}_{2}solution(inlitre)}\\ =\frac{0.0316mole}{ 0.125litre}=0.253M\end{array}$

(b)

Interpretation:

Molarity of NaHCO₃solution have to be calculated.

Concept Introduction:

Composition of a solution can be defined by expressing its concentration. The concentrations of solutions can be expressed in different ways, which are involved in the quantity of solute and the quantity of solution or solvent. Various methods are used to describe the concentration of the solution quantitatively. Some commonly used quantitative concentration terms are percent by mass, percent by volume, molarity, molality and mole fraction.

Molarity: Molarity is defined as the number of moles of solute present in one litre of the solution In expression, $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Again $\mathrm{Number}ofmolesofsolute=\frac{Massofthesolute}{Molecularweightofthesolute}$

Molarity of NaHCO₃solution is 0.106 M.

  $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Data given: Mass of NaHCO₃= 0.101 gm

Volume of NaHCO₃solution = 11.3 mL = 0.0113 L

  $\begin{array}{l}NumberofmolesofNaHC{O}_3=\frac{MassofNaHC{O}_3}{MolecularweightofNaHC{O}_3}\\ =\frac{0.101gm}{84gm/mol}=0.0012mol\end{array}$

  $\begin{array}{l}MolarityofNaHC{O}_{3}solution=\frac{NumberofmolesofNaHC{O}_3}{ Volume of NaHC{O}_{3}solution(inlitre)}\\ =\frac{0.0012mole}{ 0.0113litre}=0.106M\end{array}$

(c)

Interpretation:

Molarity of NaCl solution have to be calculated.

Concept Introduction:

Composition of a solution can be defined by expressing its concentration. The concentrations of solutions can be expressed in different ways, which are involved in the quantity of solute and the quantity of solution or solvent. Various methods are used to describe the concentration of the solution quantitatively. Some commonly used quantitative concentration terms are percent by mass, percent by volume, molarity, molality and mole fraction.

Molarity: Molarity is defined as the number of moles of solute present in one litre of the solution In expression, $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Again $\mathrm{Number}ofmolesofsolute=\frac{Massofthesolute}{Molecularweightofthesolute}$

Molarity of Na₂CO₃solution is 0.434 M.

  $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Data given: Mass of Na₂CO₃= 52.9 gm

Volume of Na₂CO₃solution = 1.15 L

  $\begin{array}{l}NumberofmolesofN{a}_{2}C{O}_3=\frac{MassofN{a}_{2}C{O}_3}{MolecularweightofN{a}_{2}C{O}_3}\\ =\frac{52.9gm}{105.99gm/mol}=0.5mol\end{array}$

  $\begin{array}{l}MolarityofN{a}_{2}C{O}_{3}solution=\frac{NumberofmolesofN{a}_{2}C{O}_3}{ Volume of N{a}_{2}C{O}_{3}solution(inlitre)}\\ =\frac{0.5mole}{ 1.15litre}=0.434M\end{array}$

(d)

Interpretation:

Molarity of KOH solution have to be calculated.

Concept Introduction:

Composition of a solution can be defined by expressing its concentration. The concentrations of solutions can be expressed in different ways, which are involved in the quantity of solute and the quantity of solution or solvent. Various methods are used to describe the concentration of the solution quantitatively. Some commonly used quantitative concentration terms are percent by mass, percent by volume, molarity, molality and mole fraction.

Molarity: Molarity is defined as the number of moles of solute present in one litre of the solution In expression, $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Again $\mathrm{Number}ofmolesofsolute=\frac{Massofthesolute}{Molecularweightofthesolute}$

Molarity of KOH solution is 0.0017 M.

  $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Data given: Mass of KOH = 0.14 mg = 0.00014 gm

Volume of KOH solution = 1.5 mL = 0.0015 L

  $\begin{array}{l}NumberofmolesofKOH=\frac{MassofKOH}{MolecularweightofKOH}\\ =\frac{0.00014gm}{56.11gm/mol}=2.5\times 10^{-6}mol\end{array}$

  $\begin{array}{l}MolarityofKOHsolution=\frac{NumberofmolesofKOH}{ Volume of KOHsolution(inlitre)}\\ =\frac{2.5\times 10^{-6}mole}{ 0.0015litre}=0.0017M\end{array}$