Chapter 3, Problem 3.123P

(a)

Interpretation Introduction

Interpretation:

Mass of Earth’s atmosphere in kilograms is to be calculated.

Concept introduction:

The conversion of one unit into another can be done using a proper conversion factor. Conversion factors are the ratios that relate the two different units of a quantity. It is also known as dimensional analysis or factor label method.

In the unit conversion problems, the given information is multiplied by the conversion factors to obtain the desired information. The unit conversion can be done as follows:

  $\left(\cancel{\text{beginning unit}}\right)\left(\frac{\text{Final unit}}{\cancel{\text{beginning unit}}}\right)=\text{Final unit}$

The conversion factor to convert minute into second is as follows:

  $\text{1 min}=\text{60 s}$

The conversion factor to convert minute into hour is as follows:

  $60\text{ min}=1\text{ h}$

The conversion factor to convert hour into days to is as follows:

  $24\text{ h}=1\text{ day}$

The conversion factor to convert days into year is as follows:

  $\text{365}\text{.25 days}= 1\text{ year }$

The conversion factor to convert hour into days to is as follows:

  $1\text{ billion year}={\text{10}}^9\text{year}$

(b)

Interpretation Introduction

Interpretation:

The amount (mol) of nitrogen present in $75.5\%$ of the mass of the atmosphere is to be calculated.

Concept introduction:

The conversion of one unit into another can be done using a proper conversion factor. Conversion factors are the ratios that relate the two different units of a quantity. It is also known as dimensional analysis or factor label method.

In the unit conversion problems, the given information is multiplied by the conversion factors to obtain the desired information. The unit conversion can be done as follows:

  $\left(\cancel{\text{beginning unit}}\right)\left(\frac{\text{Final unit}}{\cancel{\text{beginning unit}}}\right)=\text{Final unit}$

The conversion factor to convert kilograms into grams is as follows:

$\text{1 kg}={10}^3\text{ g}$