Chapter 4.3, Problem 4.7CT

(a)

Interpretation Introduction

Interpretation:

The ways by which United States changed their fuel consumption has to be described.

Concept Introduction:

Coal is a non-renewable source of energy.  That is, once it finishes, finishes forever and require millions of years for its production.  Also, burning of coal cause the emission of greenhouse gases, which can lead to global warming.

Renewable source of energy is the one that replenished naturally in very short span of time. Solar energy, wind energy etc. are examples for renewable sources.

(b)

Interpretation Introduction

Interpretation:

The fraction of energy produced by burning coal has to be estimated.

Concept Introduction:

Coal is a non-renewable source of energy.  That is, once it finishes, finishes forever and require millions of years for its production.

The chemical formula for coal is ${\text{C}}_{\text{135}}{\text{H}}_{\text{96}}{\text{O}}_{\text{9}}\text{NS}\text{.}$  It contains $\text{85\%}$ carbon by mass.