Chapter 8, Problem 8.131MP

(a)

Interpretation Introduction

Interpretation:

Balanced equation for reaction of acetic acid with sodium carbonate and the reaction of acetic acid with sodium hydrogen carbonate has to be written.

Concept Introduction:

Balanced equation

• Every chemical reaction obliges Law for conversion of mass which states the mass of total amount of the product should be equal to the total mass of the reactants as matter can neither be destroyed nor be created.
• Law of definite proportion states that a chemical compound always contains its constituent elements in a fixed ratio by mass.  It does neither depend on the source of the preparation nor depend on the method of preparation.
• A chemical equation is balanced based on the above two laws.

(b)

Interpretation Introduction

Interpretation:

Given are two reactions of acetic acid with $N{a}_{2}C{O}_3$ and $NaHC{O}_3.$  The amount of each substance, $N{a}_{2}C{O}_3$ and $NaHC{O}_3$ (in kilograms) required to neutralize $1.000$ gallon of pure acetic acid has to be determined.

(c)

Interpretation Introduction

Interpretation:

The amount of heat absorbed or liberated in the given two reactions has to be calculated in kilojoules.

Concept Introduction:

$\Delta H°$ refers to standard enthalpy change.  Change in enthalpy in a reaction and heat of formation are related by the formula,

$\Delta H_{rxn}^{°}=\Sigma \Delta H_f^{°}(product)-\Sigma \Delta H_f^{°}(reac\tan t)$

Where,

$\begin{array}{l}\Delta H_{rxn}^{°}=\text{ enthalpy change in reaction}\\ \Delta H_f^{°}(product)=\text{ enthalpy or heat of formation of product}\\ \Delta H_f^{°}(reac\tan t)=\text{ enthalpy or heat of formation of }reac\tan t\end{array}$

Heat liberated or absorbed during the reaction is,

$q=\Delta H°\times n$

Where,

$q=heat\text{ liberated or absorbed}\text{. n = no}\text{.of moles of the substance}$

If sign of ‘q’ is negative it implies heat is liberated.  If sign of ‘q’ is positive it implies heat is absorbed.