Chapter 9, Problem 9.25P

(a)

Interpretation Introduction

Interpretation:

The balanced reaction for the combustion of liquid ethanol should be identified.

Concept introduction:

• Combustion reaction takes place in presence of oxygen and results in the production of carbon dioxide and water.
• When the number of different atoms of elements in the product side is equal to that of reactants side in a chemical equation, these types of reactions are said to be a balanced reaction.

(b)

Interpretation Introduction

Interpretation:

Combustion energy should be identified.

Concept introduction: The energy for combustion can be determined by subtracting the enthalpy of formation of product from the energy of reactant as follows:

  $\left({\text{2 E}}_{{\text{CO}}_{\text{2}}}+{\text{ 3 E}}_{{\text{H}}_{\text{2}}\text{O}}\right)–\left({\text{ E}}_{\text{EtOH}}+{\text{ E}}_{{\text{O}}_{\text{2}}}\right)$

(c)

Interpretation Introduction

Interpretation:

Energy in kJ /g should be identified.

Concept introduction: Combustion enthalpy in kJ/ g can be determined by dividing the energy with a molar mass of ethanol as follows:
Combustion enthalpy $=-\text{ 1366}.\text{7 }/\text{ M}$

(d)

Interpretation Introduction

Interpretation:

Energy in kJ /mL should be identified.

Concept introduction: Multiplying the energy with the density provides the energy with kJ /mL as follows:

  $=\text{ 29}.\text{57 }\times \text{ d }$