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Chemistry Unit 9 – Gas Laws. Lesson 2 – Basic Gas Laws Book Section: 14.2 Do Now: What are the values of standard pressure and standard temperature?. Gas Laws. There are three basic gas laws discovered independently, that tell us how gases behave when certain variables are changed.
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ChemistryUnit 9 – Gas Laws Lesson 2 – Basic Gas Laws Book Section: 14.2 Do Now: What are the values of standard pressure and standard temperature?
Gas Laws • There are three basic gas laws discovered independently, that tell us how gases behave when certain variables are changed. • Those variables are: • Pressure (P) • Volume (V) • Temperature (T) – ALWAYS USE KELVIN
Boyle’s Law (Pressure v. Volume) • Pressure and volume are inversely proportional – when pressure is increased, volume is decreased. • Inverse proportion – when variables behave opposite to each other. • Equation: • P1V1 = P2V2 • It does not matter what units of pressure or volume are used, as long as both sides share the same units.
Sample Problem • A balloon contains 30.0 L of helium gas at 103 kPa. What is the volume of the helium when the balloon rises to an altitude where the pressure is only 25.0 kPa?
Sample Problem • A balloon contains 30.0 L of helium gas at 103 kPa. What is the volume of the helium when the balloon rises to an altitude where the pressure is only 25.0 kPa? • 124 L
Charles’s Law (Volume v. Temperature) • Temperature and volume are directly proportional – when temperature is increased, volume is increased. • Direct proportion – when variables behave in the same way, as a pair. • Equation (Temperature MUST be in Kelvin)
Sample Problem • A balloon inflated in a room at 24oC has a volume of 4.00 L. The balloon is then heated to a temperature of 58oC. What is the new volume if the pressure remains constant?
Sample Problem • A balloon inflated in a room at 24oC has a volume of 4.00 L. The balloon is then heated to a temperature of 58oC. What is the new volume if the pressure remains constant? • 4.46 L
Gay-Lussac’s Law (Pressure v. Temperature) • Temperature and pressure are directly proportional. (When temperature goes up, pressure goes up) • Equation (Temperature MUST be in Kelvin)
Sample Problem • Aerosol cans carry warnings on their labels that say not to incinerate (burn) them or store the cans above a certain temperature. • The gas in a used aerosol can is at a pressure of 103 kPa at 25oC. If the can is thrown onto a fire, what will the pressure be when the temperature reaches 928oC?
Sample Problem • Aerosol cans carry warnings on their labels that say not to incinerate (burn) them or store the cans above a certain temperature. • The gas in a used aerosol can is at a pressure of 103 kPa at 25oC. If the can is thrown onto a fire, what will the pressure be when the temperature reaches 928oC? • 415 kPa
HW 9-2 Due Thursday • This week: • Thursday: Absolute Zero Lab, HW 9-2 Due • Friday: Absolute Zero Lab (Lab Due Monday) • Calendar for rest of year available at www.mrcerami.com