Gases are easily compressed Gases can expand Large amount of space between particles
Compressing a gas causes pressure to increase 3 Factors Affect Gas Pressure Volume of the container (V) Measured in Liters Amount of gas (n) Measured in the number of moles Temperature Measured in Kelvins (T)
Amount of gas affects on pressure Increase in number of particle Increases in number of collisions Increase in Pressure As the amount of gas changes, the pressure changes directly Ex. When the number of moles is doubled the pressure double. Also works when the moles decreases
Gases will flow to the area with lower pressure. Ex: Deflating balloon Gas will leave the balloon into the surroundings Vacuum sealed container Gas will rush into the container
Volumes effects on pressure Decrease in volume of the container Increase in the number of collisions Increase in pressure Volume inversely affects pressure A volume decrease causes a pressure increase If the volume is halved, the pressure is doubled. Squeezing a pack of Ketchup
Temperatures affects on pressure Increase in Temperature Increase in the speed of the gas particles Increase in the number of collisions Increase in pressure Temperature directly affects pressure If the temperature double, so will the pressure Ex: Frozen balloon
Boyles Law For a given mass of gas at constant temperature, the volume of a gas varies inversely with pressure.
Boyles Law P ×V=P×V Pressure in units of kilopascals (kPa) Volume in units of liters (L)
Boyles Law Ex: The volume of a raft has an initial volume of 1.2 liters and an initial pressure of 87kPa. If the final volume was 2.9 liters what was the final pressure ? P =87kPa V=1.2L P=? V=2.9 P ×V=P×V ( P ×V)/ V =P (87x1.2)/2.9= 36 kPa
Charles Law: As the temperature of an enclosed gas increases, the volume increases, if the pressure is constant.
Charles Law: V /T =V /T Volume in units of Liters (L) Temperature in units of Kelvins (K)
Charles Law Ex: The volume of an inflated balloon at 24 ˚ C has a volume of 4 liters. The balloon is then moved to a room with a temperature of 58 ˚ C. What is the Volume? T = 24˚C+ 273 = 292 K T= 58˚C + 273 = 331 K V /T =V /T V = (VxT)/ T (4.00L x 331 K)/ 297 K= 4.46L
Gay-Lussacs Law As the temperature of an enclosed gas increases, the pressure increases, if the volume is constant. P/T=P/T Pressure: kPa Temperature: K
Gay-Lussacs Law Ex: An aerosol can is stored at 25˚C and has a pressure of 103 kPa. If the f=can is heated to 928˚C, what is the final pressure? T=25˚C + 273= 298 K T= 928˚C + 273= 1201 K P/T=P/T T(P/T)=P 103kPa x (1201 K / 298 K)= 415 kPa Or 4.15 x 10² kPa
The Combined Gas Law Calculates for situations where the amount of gas is constant. (P x V)/T= (P x V)/ T P: kPa V: L T: K
Combined Gas Law Ex: The volume of a balloon is 30.0 L at 313 K and 153 kPa pressure. What would the volume be at standard temperature and pressure (STP) STP: 273K and 101.3 kPa (P x V)/T= (P x V)/ T V= (V x P x T)/ (P x T) (30L x 53kPa x 273K)/(101.3kPa x 313K)= 39.5 L