A influência dos gases estufa no oceano Atlântico Sul: Estudo ...
Unit 7. Gas Properties Kinetic Molecular Theory Review Ideal Gases are perfect gases. They have: No...
-
Upload
timothy-floyd -
Category
Documents
-
view
215 -
download
0
Transcript of Unit 7. Gas Properties Kinetic Molecular Theory Review Ideal Gases are perfect gases. They have: No...
GASESUnit 7
Video 7.1Gas Properties
Kinetic Molecular Theory Review
Ideal Gases are perfect gases. They have:No massNo volumeNo attractive forces
When will real gases behave this way?When they are spread outTemperature is highPressure is low
Boyle’s Law Pressure and volume have
an indirect relationship.
P1V1=P2V2
What happens to a balloon if you put pressure on it? If you release it into the atmosphere?
Charles’ Law
Volume and temperature have a direct relationship.
V1/T1 = V2/T2
What happens to a car tire in the winter?
Gay-Lussac’s Law
Pressure and temperature have a direct relationship.
P1/T1 = P2/T2
Video 7.2Combined Gas Law
Combined Gas Law
P1V1 = P2V2 T1 T2
Only used when discussing initial and final conditions of a gas.
If something is held constant, cross it out of the equation.
Temperature must be in Kelvin!
Question 1
P1V1 = P2V2 T1 T2
P1V1 = P2V2
(5.6x103)(1.53) = (1.5x104)(x)
X = .571 L
Question 2 A 32.9L sample of a gas at constant
pressure increases in temperature from 25 to 45C. Should the volume increase or decrease? Calculate the new volume.
P1V1 = P2V2 T1 T2
V1 = V2T1 T2
32.9 = x . 298 318 X= 35.1 L
Question 3
A gas in a rigid container has a pressure of 3.5 atmospheres at 200K. Calculate the pressure at 273K.
P1V1 = P2V2 T1 T2
P1 = P2 T1 T2
3.5 = x .200 273
X = 4.78 atm
Video 7.3Other Gas Laws
Avogadro’s Law
Two different gases as the same temperature, volume, and pressure have the same number of molecules.
Graham’s Law of diffusion
Gases move from high to low concentrations. Lighter gases diffuse faster.
Which diffuses the fastest: He or N2?
Why will F2 and Ar diffuse at almost the same rate?
Graham’s Law of diffusion
Dalton’s Law of partial pressures The total pressure in a system of gases
equals the pressure of each individual gas combined.
Example
1. If the total pressure of a container of gases is 3 atmospheres and it contains 1 atmosphere of oxygen, 0.5 atm of nitrogen, 0.75 atm of methane, what is the partial pressure of the remaining gas?
3 – 1 - .5 - .75 = .75 atm
Harder Example
2. A mixture of gases contain 4.46 moles Ne, 0.74 moles of Ar, and 2.15 moles of Xe. Calculate the partial pressure of each gas if the total pressure is 2 atm.
PNe= (4.46/7.35)(2) = 1.21 atmPAr= (0.74/7.35)(2) = 0.201 atmPxe= (2.15/7.35)(2) = 0.585 atm
Class Notes
How do we breathe?
Why is Boyle’s law important to scuba divers?
Why is Charles’ Law important in hot air ballooning?
The general-purpose tank car in the photo before was being steam cleaned in preparation for maintenance. The job was still in progress at the end of the shift so the employee cleaning the car decided to block in the steam. The car had no vacuum relief so as it cooled, the steam condensed and the car imploded.