Chapter 4.1, Problem 4.2AFP

(a)

Interpretation Introduction

Interpretation:

Amount of each ion produced when $2\text{mol}$ of potassium perchlorate is dissolved in water is to be calculated.

Concept introduction:

A solution is a combination of two parts: solute and solvent. A solute is the substance that is present in small quantity and solvent is the substance in which solute is dissolved. When water acts as a solvent then it is known as an aqueous solution.

Ionic compounds are the compounds that are composed of charged ions. They are held together by electrostatic forces. These compounds dissociate into ions when dissolved in water. Potassium perchlorate $\left({\text{KClO}}_4\right)$ is an example of an ionic compound and dissociates into ions when dissolved in water. The dissociation reaction of ${\text{KClO}}_4$ is:

${\text{KClO}}_4\left(s\right)\to {\text{K}}^{+}\left(aq\right)+{\text{ClO}}_4^{-}\left(aq\right)$

The expression to calculate the amount of ions in moles is as follows:

$\text{amount}\text{of}\text{ion}\left(\text{mol}\right)=\left(\text{moles of compound}\left(\text{mol}\right)\right)\left(\frac{\text{moles of ion}\left(\text{mol}\right)}{1\text{mole of compound}}\right)$

(b)

Interpretation Introduction

Interpretation:

Amount of each ion produced when $354\text{g}$ of magnesium acetate is dissolved in water is to be calculated.

Concept introduction:

A solution is a combination of two parts: solute and solvent. A solute is the substance that is present in small quantity and solvent is the substance in which solute is dissolved. When water acts as a solvent then it is known as an aqueous solution.

Ionic compounds are the compounds that are composed of charged ions. There are held together by electrostatic forces. These compounds dissociate into ions when dissolved in water. Magnesium acetate $\left(\text{Mg}{\left({\text{C}}_2{\text{H}}_3{\text{O}}_2\right)}_2\right)$ is an example of an ionic compound and dissociates into ions when dissolved in water. The dissociation reaction of $\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_2$ is:

$\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_2\left(s\right)\to {\text{Mg}}^{2+}\left(aq\right)+2{\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_2^{-}\left(aq\right)$

The expression to calculate the moles of the compound is as follows:

$\text{moles of compound}\left(\text{mol}\right)=\left[\begin{array}{c}\left(\text{given mass of compound}\left(\text{g}\right)\right)\\ \left(\frac{\text{1 mole of compound}}{\text{molecular mass of compound}\left(\text{g}\right)}\right)\end{array}\right]$

(c)

Interpretation Introduction

Interpretation:

Amount of each ion produced when $1.88\times {10}^{24}$ formula unit of ammonium chromate is dissolved in water is to be calculated.

Concept introduction:

A solution is a combination of two parts: solute and solvent. A solute is the substance that is present in small quantity and solvent is the substance in which solute is dissolved. When water acts as a solvent then it is known as an aqueous solution.

Ionic compounds are the compounds that are composed of charged ions. There are held together by electrostatic forces. These compounds dissociate into ions when dissolved in water. Ammonium chromate $\left({\left({\text{NH}}_4\right)}_2{\text{CrO}}_4\right)$ is an example of an ionic compound and dissociates into ions when dissolved in water. The dissociation reaction of ${\left({\text{NH}}_4\right)}_2{\text{CrO}}_4$ is:

${\left({\text{NH}}_4\right)}_2{\text{CrO}}_4\left(s\right)\to 2{\text{NH}}_4^{+}\left(aq\right)+{\text{CrO}}_{{}_4}^{-}\left(aq\right)$

A formula unit is used for ionic compound to represent their empirical formula. The expression to calculate the moles of the compound is as follows:

$\text{moles of compound}\left(\text{mol}\right)=\left[\begin{array}{c}\left(\text{given formula unit of compound}\left(\text{FU}\right)\right)\\ \left(\frac{\text{1 mole of compound}}{\text{6}\text{.022}\times {\text{10}}^{23}\text{FU}}\right)\end{array}\right]$