gases,liquids & solids
DESCRIPTION
GASES,LIQUIDS & SOLIDS. COMPOSITION OF AIR: Minor Components. Also, variable amounts of: H 2 O (0 – 7 %) CO 2 (0.01 – 1 %) CO(0 – 0.000002 %) NO 2 (0 - 0.000002 %) SO 2 (0 - 0.0001 %) O 3 (0 – 0.000007 %). COMPOSITION OF AIR: (contd.). Greenhouse Gases:. - PowerPoint PPT PresentationTRANSCRIPT
GASES,LIQUIDS & SOLIDS
Gases Liquids SolidsNo 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 CaCO3 CaO + CO2
• O2 4NaNO3 Na2O + N2 + 5O2
• O2 KClO4 KCl + 2O2
• NH3 NH4Cl 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 orR = 8.3145 J mol-1 K-1
GAS DENSITY & MOLAR MASS