Chapter U4, Problem C15.4RE

(a)

Interpretation Introduction

Interpretation:

The solution with the greatest concentration out of 100 mL of given solutions needs to be determined.

Concept introduction:

The molecular mass of a 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:

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

Answer to Problem C15.4RE

Since the volume is the same for all the given solutions, therefore, the NaOH and KCl will have a higher concentration.

Explanation of Solution

The concentration mainly depends on the number of moles and volume. Since the volume is the same for all the given solutions, therefore, the NaOH and KCl will have a higher concentration than the PbCl₂ solution which is only 0.5 M compared to 1.0 M NaOH and KCl.

(b)

Interpretation Introduction

Interpretation:

The solution with greatest mass out of 100 mL of given solutions needs to be determined.

Concept introduction:

The molecular mass of a 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:

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

Answer to Problem C15.4RE

${\text{PbCl}}_{\text{2}}$ solution has the greatest mass.

Explanation of Solution

Molar mass of NaOH = 39.9 g/mol

Molar mass of KCl = 74.5 g/mol

Molar mass of PbCl₂ = 278 g/mol

Concentration = 1.0 M

Volume = 100 mL = 0.1 L

Calculate mass of each:

$\begin{array}{c}\text{Concentration = }\frac{\text{mass}}{\text{molar mass×volume}}\\ \text{mass = Concentration×molar mass×volume}\\ \text{mass of NaOH = 1}\text{.0 M ×39}\text{.9 g/mol × 0}\text{.1 L}\\ \text{ = 3}\text{.99 g}\\ \text{mass of KCl = 1}\text{.0 M ×74}\text{.5 g/mol × 0}\text{.1 L}\\ \text{ = 7}\text{.45 g}\\ {\text{mass of PbCl}}_{\text{2}}\text{ = 0}\text{.5 M × 278 g/mol × 0}\text{.1 L }\\ \text{= 13}\text{.9 g}\end{array}$

(c)

Interpretation Introduction

Interpretation:

The solution with maximum number of moles needs to be determined if volume is 100 mL for each; 0.1 M NaOH, 1.0 M KCl and 0.5 M pbCl₂ solution.

Concept introduction:

The molecular mass of a 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:

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

Answer to Problem C15.4RE

NaOH and KCl will have most of the moles.

Explanation of Solution

Molar mass of NaOH = 39.9 g/mol

Molar mass of KCl = 74.5 g/mol

Molar mass of PbCl₂ = 278 g/mol

Concentration = 1.0 M

Volume = 100 mL = 0.1 L

Calculate moles of each:

$\begin{array}{c}\text{Concentration = }\frac{\text{moles}}{\text{volume}}\\ \text{Moles = Concentration× volume}\\ \text{Moles of NaOH = 1}\text{.0 M × 0}\text{.1 L }\\ \text{= 0}\text{.1 moles}\\ \text{Moles of KCl = 1}\text{.0 M × 0}\text{.1 L }\\ \text{=0}\text{.1 moles}\\ {\text{Moles of PbCl}}_{\text{2}}\text{ = 0}\text{.5 M × 0}\text{.1 L}\\ \text{ = 0}\text{.05 moles}\end{array}$

(d)

Interpretation Introduction

Interpretation:

The solution with maximum number of moles of ions needs to be determined if volume is 100 mL for each; 0.1 M NaOH, 1.0 M KCl and 0.5 M pbCl₂ solution.

Concept introduction:

The molecular mass of a 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:

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

Answer to Problem C15.4RE

PbCl₂will have most of the moles of ions.

Explanation of Solution

Molar mass of NaOH = 39.9 g/mol

Molar mass of KCl = 74.5 g/mol

Molar mass of PbCl₂ = 278 g/mol

Concentration = 1.0 M

Volume = 100 mL = 0.1 L

Calculate mass of each:

$\begin{array}{c}\text{Concentration = }\frac{\text{moles}}{\text{volume}}\\ \text{Moles = Concentration× volume}\\ \text{Moles of NaOH = 1}\text{.0 M × 0}\text{.1 L }\\ \text{= 0}\text{.1 moles}\\ \text{ = 0}\text{.1 }\times \text{2 = 0}\text{.2 moles of ions}\\ \text{Moles of KCl = 1}\text{.0 M × 0}\text{.1 L }\\ \text{=0}\text{.1 moles}\\ \text{= 0}\text{.1 }\times \text{2 = 0}\text{.2 moles of ions}\\ {\text{Moles of PbCl}}_{\text{2}}\text{ = 0}\text{.5 M × 0}\text{.1 L}\\ \text{ = 0}\text{.05 moles}\\ \text{= 0}\text{.05 }\times \text{3 = 0}\text{.15 moles of ions}\end{array}$