Dressen-Gas Laws

Pressure, Volume, Temperature:

Pressure, Volume, Temperature Let’s see what we already know about these three variables … Gas Law Program

Boyle’s Law:

Boyle’s Law Charles Boyle, studied the relationship between pressure , p, and volume , V, in the mid-1600s. When he doubled the pressure on a sample of gas at constant temperature, its volume was reduced by one-half. pressure volume

Boyle’s Law: Graphically:

Boyle’s Law: Graphically constant temperature -inverse relationship

Boyle’s Law: Formula:

Boyle’s Law: Formula P 1 = initial pressure V 1 = initial volume P 2 = final pressure V 2 = final volume If you know three of the four, you can calculate the fourth. P 1 V 1 = P 2 V 2

Boyle’s Law: Sample Problem:

Boyle’s Law: Sample Problem P 1 V 1 = P 2 V 2 A sample of oxygen gas has a volume of 150. ml when its pressure is 0.947 atm. What will the volume of the gas be at a pressure of 0.987 atm if the temperature does not change? P 1 V 1 = P 2 V 2 P 2 = P 2 P 1 V 1 = V 2 P 2 V 2 = (0.947)(150.) = 144 ml of O 2 (.987)

Charles’s Law:

Charles’s Law Jacques Charles discovered the relationship between volume and temperature in 1787. The law states that the volume of a sample of gas at constant pressure varies directly with Kelvin temperature. 1783 - 1st hydrogen balloon volume temperature

Charles’s Law: Graphically:

Charles’s Law: Graphically constant pressure -direct relationship

Charles’s Law: Formula:

Charles’s Law: Formula V 1 T 1 = V 2 T 2 V 1 = initial volume T 1 = initial temperature V 2 = final volume T 2 = final temperature If you know three of the four, you can calculate the fourth.

Charles’s Law: Sample Problem:

Charles’s Law: Sample Problem A sample of neon gas occupies a volume of 752 ml at 25 o C. What volume will the gas occupy at 50 o C if the pressure remains constant? T 2 V 1 T 2 V 2 T 1 T 2 T 2 V 1 T 1 V 2 = (752)(273 +50) = 815 ml Ne (273 + 25) V 1 T 1 = V 2 T 2 = = V 2

Gay-Lussac’s Law:

Gay-Lussac’s Law Joseph Gay-Lussac is credited with discovering relationship between pressure and temperature, but the discovery should actually go to Guillaume Amontons (1699). There is a Gay-Lussac's law but it has to do with the ratio of the volumes of gases in a chemical reaction, the "law of combining volumes". pressure temperature

Gay-Lussacs Law: Graphically:

Gay-Lussacs Law: Graphically constant volume -direct relationship

Gay-Lussac’s Law: Formula:

Gay-Lussac’s Law: Formula P 1 T 1 = P 2 T 2 P 1 = initial pressure T 1 = initial temperature P 2 = final pressure T 2 = final temperature If you know three of the four, you can calculate the fourth.

Gay-Lussac’s Law: Sample Problem:

Gay-Lussac’s Law: Sample Problem The gas in an aerosol can is at a pressure of 3.00 atm at 25 o C. The can warns not to allow the temperature to get above 52 o C. What would the pressure of the can be at 52 o C? T 2 P 1 T 2 P 2 T 1 T 2 T 2 P 1 T 1 P 2 = (3.00)(273 +52) = 3.25 atm (273 + 25) P 1 T 1 = P 2 T 2 = = P 2

Slide 14:

NOVA: Race for Absolute Zero Try not to lose your head when you are doing chemistry and Why you should always wear your safety goggles