Chapter 13, Problem 68A

(a)

Interpretation Introduction

Interpretation:

The total pressure of the gases in the system is to be determined.

Concept Introduction :

According to Dalton’s law of partial pressure of gases, the sum of the partial pressure of the individual gases is equal to the total pressure of the system.

Answer to Problem 68A

The total pressure is $\text{1450}\text{torr}$ .

Explanation of Solution

The entire pressure of the system is equal to the sum of partial pressures of different gases.

The entire pressure is given as,

  ${\text{P}}_{\text{total}}\text{=}{\text{P}}_{{\text{H}}_{\text{2}}}\text{+}{\text{P}}_{{\text{N}}_{\text{2}}}\text{+}{\text{P}}_{{\text{O}}_{\text{2}}}$

  $\begin{array}{l}{\text{P}}_{\text{total}}\text{=}{\text{P}}_{{\text{H}}_{\text{2}}}\text{+}{\text{P}}_{{\text{N}}_{\text{2}}}\text{+}{\text{P}}_{{\text{O}}_{\text{2}}}\\ \text{=}\text{325+475+650}\\ \text{=1450}\text{torr}\end{array}$

(b)

Interpretation Introduction

Interpretation:

The gas which contains a greater number of moles is to be explained.

Concept Introduction:

According to the ideal gas equation, the pressure of the gas is directly proportional to the number of moles of the gas.

Answer to Problem 68A

Oxygen gas contains the greatest number of molecules.

Explanation of Solution

The number of moles is calculated as;

  $\text{n =}\frac{\text{PV}}{\text{RT}}$

In the above expression, we take the volume of the gas is 1L

So, $\text{n =}\frac{\text{P}}{\text{RT}}$

Here, the value of gas constant and temperature is the same for all gases. Therefore, the number of moles is directly based on the pressure of the gas. So, out of the given pressures of different gases, the pressure of oxygen gas is maximum. So, oxygen gas contains the greatest number of moles.