Unit 9

 Independent particles, moving in straight lines  Change direction with collisions  Travel randomly  Assume shape of container and volume of their container  Large amount of empty space  Compressible  No attractive forces between particles

 Fluidity – gas particles glide and flow past each other  Expansion – fill any container  Compressibility – can decrease the volume  Diffusion – spontaneous mixing of two gases, flow until evenly distributed. Flow from an area of high concentration to an area of low concentration.

 Dependent on the force of the collision and the number of collisions that occur between particles.  Pressure = Force/Area  Atmospheric or barometric pressure – results from collisions of air molecules with objects on earth.

 Manometer  Barometer  Developed by Evangelista Torricelli  Pressure gauge

 SI unit = Pascal (Pa)  A pascal is small so normally the kilopascal (kPa) is used which is 1000 Pascal.  Atmosphere (atm)  1 atm is the atmospheric pressure at sea level.  Pounds per square inch (psi)  Millimeters of mercury (mmHg)  Torr

 Named after Robert Boyle  It says that at a constant temperature pressure and volume are inversely proportionate.  As volume goes up the pressure goes down and vice versa. P 1 V 1 =P 2 V 2

 Weather Balloon  Helium vs. Air  Equilibrium  Airplanes  Pressure as you climb  Volume

 Bike Pump

The maximum volume of air that a weather balloon can hold without rupturing is 22,000L. It is designed to reach an altitude of 30 km. At this altitude, the atmospheric pressure is o.o125 atm. What maximum volume of helium gas should be used to inflate the balloon before it is launched?

Two liters of air at atmospheric pressure are compressed into the 0.45 L canister of a warning horn. If its temperature remains constant, what is the pressure of the compressed air in the horn?

 Lid in refrigerator  Air hot  Cools down and sinks  Tires on the road  Too inflated pops tire

 Balloon

 A balloon is filled with 3.0 L of helium at 22 o C and 760 mmHg. It is then placed outdoors on a hot summer day when the temperature is 31 o C. If the pressure remains constant what will the volume of the balloon be?

 Aerosol can in fire  Pressurized can  Increase temp= explosion

A toy balloon has an internal pressure of 1.05 atm and a volume of 5.0L. If the temperature where the balloon is released is 2o o C, what will happen to the volume when the balloon rises to an altitude where the pressure is 0.65 atm and the temperature is C?

 Hyper: above or excessive  Hyperbaric refers to pressure that is greater than normal  Hyperbaric chambers uses:  cure burns  Decompression sickness  Anemia  Infections