Chapter 4, Problem 4.154P

(a)

Interpretation Introduction

Interpretation:

The grams of ${\text{MgCl}}_2$ that must dissolve to equal the ion concentration of $12.4\text{ g}$ of $\text{NaCl}$ is to be calculated.

Concept introduction:

Stoichiometry of a reaction is utilized to determine the amount of any species in the reaction by the relationship between the reactants and products.

Consider the general reaction,

$\text{A}+2\text{B}\to 3\text{C}$

One mole of $\text{A}$ reacts with two moles of $\text{B}$ to produce three moles of $\text{C}$. The stoichiometric ratio between A and B is 1:2, the stoichiometric ratio between A and C is 1:3 and the stoichiometric ratio between B and C is 2:3.

(b)

Interpretation Introduction

Interpretation:

The mass of $\text{CaS}$ that must be dissolved is to be calculated.

Concept introduction:

Stoichiometry of a reaction is utilized to determine the amount of any species in the reaction by the relationship between the reactants and products.

Consider the general reaction,

$\text{A}+2\text{B}\to 3\text{C}$

One mole of $\text{A}$ reacts with two moles of $\text{B}$ to produce three moles of $\text{C}$. The stoichiometric ratio between A and B is 1:2, the stoichiometric ratio between A and C is 1:3 and the stoichiometric ratio between B and C is 2:3.

(c)

Interpretation Introduction

Interpretation:

Among the three salt solutions that would dissolve the most protein is to be identified.

Concept introduction:

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. ${\text{MgCl}}_2$, $\text{NaCl}$ and $\text{CaS}$ are the ionic compound that dissociates into ions when dissolved in water. The dissociation reaction of these ionic compounds is as follows:

$\begin{array}{c}\text{NaCl}\left(s\right)\rightleftharpoons {\text{Na}}^{+}\left(aq\right)+{\text{Cl}}^{-}\left(aq\right)\\ {\text{MgCl}}_2\left(s\right)\rightleftharpoons {\text{Mg}}^{2+}\left(aq\right)+2{\text{Cl}}^{-}\left(aq\right)\\ \text{CaS}\left(s\right)\rightleftharpoons {\text{Ca}}^{2+}\left(aq\right)+{\text{S}}^{2-}\left(aq\right)\end{array}$