Pressure and Phase Relationships Ch. 13 States of Matter.
-
Upload
myles-reynolds -
Category
Documents
-
view
217 -
download
0
Transcript of Pressure and Phase Relationships Ch. 13 States of Matter.
Pressure and Phase Relationships
Ch. 13 States of Matter
Fahrenheit, Celsius and Kelvin• Fahrenheit based on
reference temperatures of brine solution at 0 and in mouth at 96 or wife’s armit
• Celsius based on freezing pt and boiling point of water] F = 1.8C + 32
• Kelvin based upon absolute zero and no negative values K = C + 273
Pressure
• Pressure: Defined as force per unit area caused by gas molecules colliding with surface
• P = F/A• 1 Pa = 1 N/m2
Temperature: defined as a measure of the AVERAGE kinetic energy of a substance (this means that some molecules are moving faster than average and some slower than average)
Liquid-Vapor EquilibriumThe temperature and pressure at which equal amounts of high energy liquid molecules A are escaping to become vapor and vapor molecules B are being slowed down and trapped at surface to return to liquid
Barometer (or manometer) measures pressure
• SI unit is the pascal (1 Pa = 1 N/m2) or kilopascal kPa
• Meteorologists (weather) like mmHg, the height the atmospheres pressure pushes a liquid column upward (more dense liquids don’t get pushed as high and Hg is very dense)
• mmHg are also called Torrs, so 1mmHg = 1Torr
Gas molecules in the atmosphere
• A standard atmosphere (atm) of pressure is defined as
typical air pressure at earth mean sea level
Pressure conversions
• This means 760mmHg = 14.7psi and 101.3kPa = 760 Torr as well
1 atmosphere is a measure of the normal pressure at sea level
1 atm = 101.3kPa = 101,300 Pa = 760 mmHg = 760 Torr = 14.7 psi
A typical atmospheric pressure in Fort Collins CO might be 690 mmHg. Convert this to atmospheres of pressure.
690mmHg x 1 atm = 0.91 atm
760mmHg
Convert the same pressure above into both psi and Torr
13.3 psi and 690 Torr
Phase Diagram of Water