Chapter 4, Problem 1RQ

Summary Introduction

Introduction:

The pressure exerted by the atmosphere is called the barometric pressure or the atmospheric pressure. The partial pressure that a specific gas exerts in the atmosphere is the pressure that the gas exerts when it occupies the same value on its own. This is calculated by multiplying the barometric pressure of the gas with its percentage in the atmosphere.

Answer to Problem 1RQ

Correct answer:

The partial pressure of oxygen will be 304 mm Hg. This is calculated with help of equating the percentage of oxygen and barometric pressure.

Explanation of Solution

Explanation for the correct answer:

Option (C) is 304 mm Hg. The atmospheric pressure in the given case is 760 mm Hg and the percentage of oxygen is given as 0.4. The equation that is used for calculating the value is given below:

$\begin{array}{c}\text{Partial pressure of gas}=\text{percentage of the gas present}\times \text{barometric pressure}\\ {\text{Partial pressure of oxygen (P}}_{\text{O2}}\text{)}=\text{0}\text{.4}\times \text{760 mm Hg}\\ =\text{304 mm Hg}\end{array}$

Hence, option (C) is correct.

Explanation for the incorrect answers:

Option (A) is 159 mm Hg. According to the above mentioned equation, the value of the partial pressure of oxygen will not be 159 mm Hg. So, it is an incorrect option.

Option (B) is 215 mm Hg. The value of partial pressure of oxygen is calculated above, using an equation. The value calculated is not equal to 215 mm Hg. So, it is an incorrect option.

Option (D) is 560 mm Hg. The calculations made above indicate that the partial pressure value is not 560 mm Hg. So, it is an incorrect option.

Hence, options (A), (B), and (D) are incorrect.

Conclusion

The partial pressure of a specific gas is calculated by multiplying the values of barometric pressure and the percentage of the gas. This partial pressure is the pressure that oxygen exerts in the mixture of gases.