KMT, Graham’s Law &amp; Real Gases

1 / 19

# KMT, Graham’s Law &amp; Real Gases - PowerPoint PPT Presentation

KMT, Graham’s Law &amp; Real Gases. Kinetic Molecular Theory. 1. Volume of individual particles is  zero. 2. Collisions of particles with container walls cause pressure exerted by gas. Kinetic Molecular Theory. 3. Particles exert no forces on each other.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'KMT, Graham’s Law &amp; Real Gases' - toyah

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### KMT, Graham’s Law & Real Gases

Kinetic Molecular Theory

1. Volume of individual particles is  zero.

2. Collisions of particles with container walls cause pressure exerted by gas.

Kinetic Molecular Theory

3. Particles exert no forces on each other.

4. Average kinetic energy Kelvin temperature of a gas.

Equations Related to KMT

Kelvin temperature is an index of the random motions of gas particles (higher T means greater motion.)

(The derivation of this equation can be found in many college physics texts)

Root Mean Square Speed
• Average velocity of the gas particles
• uRMS = (3RT/M)1/2
• M is in Kg
• R = 8.3145 J/K mol

Diffusion: describes the mixing of gases. The rate of diffusion is the rate of gas mixing.

Effusion: describes the passage of gas into an evacuated chamber.

Graham’s Law

Effusion:

Diffusion:

### Real Gases

Must correct ideal gas behavior when at high pressures and low temperatures

-volume of molecules becomes significant

-attractive forces become important

The rate of effusion of a particular gas was measured and found to be 24.0 mL/min. Under the same conditions, the rate of effusion of pure methane gas is 47.8 mL/min. What is the molar mass of the unknown gas?

Real Gases – van der Waal’s Equation

corrected pressure

corrected volume

Van der Waal’s constants, a and b, are dependent on the type of gas molecule (see table 5.3)

Practice Problems

Which gas will diffuse faster, ammonia (NH3) or carbon dioxide (CO2)? What are their relative rates of diffusion?

Freon-12 is used as a refrigerant in central home air-conditioners. The rate of effusion of Freon-12 to Freon-11 (molar mass = 137.4 g/mol) is 1.07:1. The formula of Freon-12 is one of the following: CF4, CF3Cl, CF2Cl2, CFCl3 or CCl4