lesson4.4 gas laws pt 2 - san leandro usd / · pdf filelsiji.cupc!t 00 c 100 ioocc ... v olume...
TRANSCRIPT
Lesson 4.4
The Gas Laws, part 2 Temperature, Pressure, and Charles’ Law
I. SI Temperature • 0 K is absolute zero • You can’t get colder because the molecules
stop moving. • Conversion factors: • K = °C + 273.15 • °C = 5/9 (°F – 32) • °F = 9/5 (°C) + 32
I. SI Temperature • Comparison…
II. STP • STP stands for standard temperature and
pressure. • It is a reference point that chemists use to
make measurements of a gas (volume, density, vapor pressure, etc.)
• Standard Temperature: 0°C (273 K) • Standard Pressure: 1 atm (760 torr)
II. STP • Molar Volume of a Gas • All gases have volume of 22.4 L at STP. • This is true for every gas no matter the molar
mass.
III. Charles’ Law • Liquid nitrogen has a boiling temperature of
-196°C. • If you put an inflated balloon in liquid nitrogen it
shrinks.
III. Charles’ Law • The volume and temperature of a gas are
directly proportional. • Equations: • V = kT or V = k
T
€
V1T1
=V2T2
T must be in Kelvin!
III. Charles’ Law • Practice: A sample of neon gas occupies a
volume of 752 mL at 25°C. What volume will the gas occupy at 50°C if the pressure remains constant?
• Answer: 815 mL