Determine the partial pressure of each gas as shown in this figure. Note: The relative numbers of each type of gas are depicted in the figure.

mg src=Images/HTML_99425-13-72QAP_image001.jpg alt="" align="top"/>

Interpretation:

The partial pressure of each gas should be calculated.

Concept Introduction:

Dalton’s law of partial pressure: In a container for mixture of gases, the total pressure is equal to the sum of partial pressures of all the gases present in the container. The partial pressure is the pressure exerted by a gas if it is the only gas present in the container.

Let a mixture of three gases with partial pressures P1, P2 and P3, the total pressure of the gas will be sum of these partial pressures as follows:

PT=P1+P2+P3

This is the Dalton’s law of partial pressure.

The behaviour of gases is assumed to be ideal thus, partial pressure of gases can be calculated from an ideal gas equation as follows:

PV=nRT

Here, P is pressure, V is volume, n is number of moles, R is Universal gas constant and T is temperature of the gas.

The pressure exerted by an ideal gas depends on the number of gas particles, this does not depend on the nature of particles of gas. The two important things concluded from it will be:

1. The volume of gases is important.
2. The forces in between the particles of gas is not important.

Given Information:

Total pressure of container is 1.00 atm.

Calculation:

From the diagram, there are three types of gas present in the container. The number of moles of He gas (blue balls) is 5 mol, number of moles of Neon gas (Red balls) is 3 mol and number of moles of argon gas (purple balls) is 2 mol.

The total number of moles of gases in the container will be:

nT=nHe+nNe+nAr

Putting the values,

nT=(5+3+2) mol=10 mol

The mole fraction of each gas can be calculated using the following formula:

X=nnT

For Helium, mole fraction will be:

XHe=nHenT=5 mol10 mol=0.5

Similarly, for neon mole fraction will be:

XNe=nNenT=3 mol10 mol=0.3

And, for Argon gas it can be calculated as follows:

XAr=nArnT=2 mol10 mol=0