ou have two rigid gas cylinder. Gas cylinder A has a volume of 48 . 2 L and contains N 2 ( g ) at 8 . 35 atm at 25  ° C Gas cylinder B has a volume of 22 .0  L and contains He ( g ) at 25  ° C . When the two cylinders are connected with a valve of negligible volume and the gases are mixed, the pressure in each cylinder becomes 8 . 71 atm. (Assume no reaction when the gases are mixed.)

How many nitrogen molecules are present?

What is the total number of moles of N 2 ( g ) mt after the gases are mixed?

What was the beginning pressure of cylinder B containing only the He(g) (i.e., before the valve urns connected)?

Think about the He(g) before and after the cylinders were connected. Graph the relationship between pressure and volume (without numbers) for the He(g) showing this change, and explain your answer, making sure to address the variables P, V, n and T.

(a)

Interpretation:

The number of molecules of nitrogen should be determined.

Concept Introduction:

When two non-reactive gases mix, the pressure, volume and temperature could be change. The new pressure, volume and temperature can be calculated with the help of ideal gas equation.

The ideal gas equation is given by:

PV = nRT.

Given information:

• Pressure = 8.35 atm.
• Volume = 48.2 L.
• Temperature=25°C = 273+25 = 298 K.
• R = gas constant = 0.0821 L.atm/ K. mol.

PV = nRT

8.35 atm × 48.2 L = n × 0.0821 L.atm / K.mol × 298 K

n=8

(b)

Interpretation:

To calculate the total number of moles of both nitrogen and helium gas after gases are mixed.

Concept Introduction:

When two non-reactive gases mix, the pressure, volume and temperature could be change. The new pressure, volume and temperature can be calculated with the help of ideal gas equation.

(c)

Interpretation:

The beginning pressure of cylinder B having Only helium gas should be calculated.

Concept Introduction:

When two non-reactive gases mix, the pressure, volume and temperature could be change. The new pressure, volume and temperature can be calculated with the help of ideal gas equation.

(d)

Interpretation:

The graph for the relationship between pressure and volume for the helium gas showing helium gas before and after the cylinders were connect should be drawn and also explain the answer by addressing variables P, V, n and T.

Concept Introduction:

When two non-reactive gases mix, the pressure, volume and temperature could be change. The new pressure, volume and temperature can be calculated with the help of ideal gas equation.