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