GASES,LIQUIDS & SOLIDS
Gases
Liquids
Solids
No fixed
volume.
Expand to
fill container.
Fixed volume.
Conform to shape of
container.
Constrained by
gravity
Fixed volume &
fixed dimensions.
Resist deformation
(changes of shape)
COMPOSITION OF AIR:
Minor Components
Also, variable amounts of:
H2O (0 – 7 %)
CO2 (0.01 – 1 %)
CO (0 – 0.000002 %)
NO2 (0 - 0.000002 %)
SO2 (0 - 0.0001 %)
O3 (0 – 0.000007 %)
COMPOSITION OF AIR:
(contd.)
• Greenhouse Gases:
COMPOSITION OF AIR:
(contd.)
• Greenhouse Gases: CO2 & CH4
COMPOSITION OF AIR:
(contd.)
• Radon - Accumulates under houses
COMPOSITION OF AIR:
(contd.)
• Radon - Accumulates under house
• Arises from radioactive decay of traces
of Actinides, typically found in Granite!
NATURAL GAS
• CH4 - FOUND WITH Oil deposits.
• He - Up to 4 % in natural gas deposits
WATER VAPOR
• H2O from evaporation of water from
surfaces of Lakes, Rivers, Oceans (80
% of Earth’s surface)
GASES FROM HEATING
SOLIDS
•
•
•
•
CO2
O2
O2
NH3
CaCO3
4NaNO3
KClO4
NH4Cl
CaO + CO2
Na2O + N2 + 5O2
KCl + 2O2
NH3 + HCl
• Also: Gases (H2) from metals and acids,
also from some metals and water (Li,
Na).
GAS PRESSURE
• Results from gravitational force on Earth’s
atmospheric gases (several miles deep).
• Measure with Barometer.
• P = Pressure = gdh
– g = accel. due to gravity
– d = density of liquid column
– h = height of column
PRESSURE
MEASUREMENTS
•
•
•
•
•
•
•
1 Atmosphere (atm.) = 760 mm Hg
d H2O = 1.00 g cm-3
d Hg = 13.6 g cm-3
For same P (= 1 atm.
= 760 mm Hg
= 760 x 13.6 mm H2O = 10.336 m
= 33.91 ft H2O
PRESSURE
MEASUREMENTS
• Pressure usually meaured in:
• (a) mm Hg (torr) 1 atm. – 760 mm Hg
• (b) Pa (PASCALS) = N m-2 = kg m-1 s-1
• 1 Atm. = 101.325 kPa
• 1 bar = 105 kPa = approx. 1 atm.
• (= 0.9869 atm.)
PRESSURE
MEASUREMENTS
• Common measure (engineering):
– psi = Pounds per square inch
psig= Pounds per square inch, gauge
– ( add current atmospheric pressure to convert to
Absolute pressure)
– 1 atm. = 14.7 psi
TEMPERATURE
• C(elcius) vs. F(ahrenheit)
• F = C x 9/5 + 32
• C = (F-32) x 5/9
• Absolute Temperature (K)
• At 0K, all gases have 0 volume
• K = 0C + 273.15
IDEAL GAS LAW
• PV = Nrt
• or P1V1 = P2 V2
n1 T1
n2 T2
AVOGADRO’S LAW
• 1 L. of all gases contains the same no. of
molecules at the same T & P
• At STP (= 1 atmos. And 0 C), 1 mol. of any
gas occupies 22.4 L
Aso R= 1 atm. x 22.4 L
1 mol x 273.15K
= 0.082057 L. atm.mol-1 K-1
UNIVERSAL GAS
CONSTANT
R = 0.082057 L. atm.mol-1 K-1 or
R = 8.3145 J mol-1 K-1
GAS DENSITY & MOLAR
MASS