QUICK CMM NOTESHABER:Reaction conditions: Reactants: N2 and H2
kept in 1:3 ratio Temperature: 400oC to 500oC Pressure: 20-25MPa
Catalyst: magnetite Recycling of unused reactants and constant
liquefaction
IONSWhy monitor ions? Lead is toxic ingestion from polluted
soils Lead biologically mimics other metals Neurological problems,
damage to kidneys, anaemia, etc.
Testing for ions? Flame Test: Platinum wire cleaned and dipped
into solution of HCl, then dipped into salt that will be tested.
Calcium: brick redBarium: apple greenCopper: blue greenSodium:
yellowStrontium: Scarlet
Precipitation Tests (solubility rules) All Group I and NH4+ are
soluble All NO3- are soluble
All Cl, Br-, and I- are soluble except Pb2+ and Ag+ All SO42+
are soluble except Pb2+, Ag+, Ca2+, and Ba2+
OH- salts are insoluble except with Group I, NH4+ and Ba2+
CO32-, O2-, and PO43- are insoluble except group I and NH4+
Further Tests: Iron compounds: Add NaOH, brown indicates Fe(OH)3
while green/white means Fe(OH)2 Calcium/Barium: Flame test, or add
NaF because CaF2 will form precipitate Nitrates: Add FeSO4, then
slowly add H2SO4. A brown ring should form Phosphates: Add Ba2+ to
alkaline solution and a white precipitate should form
Atomic Absorption Spectroscopy: Technique to accurately measure
concentration of metal ions in solution, especially if they are in
low concentrations when gravimetric analysis fail Works based on
principle that each metallic element absorbs specific wavelengths
of light Sample is fed to flames and vaporised, light will pass
through to detector Absorption vs concentration graph Advantages:
very accurate, valid, sensitive, simple, and cheap to run
Disadvantages: the identity of the ion must be known, cant
differentiate valencies Impact: Understanding of trace elements
like copper, zinc, cobalt and molybdenum AAS found out roles and
identities of these elements, etc. health realted AAS can also find
heavy metal concentrations in water
Atmosphere Troposphere (0-15km): contains 75% of the air
Stratosphere: (15-50): contains ozone layer, with troposphere they
contain 99.9% of gases Mesosphere (50-85): cold since there is
little particles Thermosphere: 85+ : very high F absorbed resulting
in higher temperatures
Pollutants:CO2,CO, NOx. SO2, Ozone, and organic. All from
burning fuels, etc.
Coordinate covalent bond: Bond in which the bonding pair of
electrons is wholly donated by only one of the bonding atoms.
CFCs and Halons: CFC: contains carbon, fluorine and chlorine.
Developed to replace NH3 as refrigerant Halons: contains carbon,
bromine and fluorine and maybe chlorine. Developed for fire
extinguishers.
Ozone destruction:Show chlorine radical breaking off CFC and
attacking ozone
Monitoring O3 Spectrophotometers: measures intensity of light
from sun at wavelength that ozone absorbs. Ground based: points
upwards to stratosphere Satellite based: Total ozone mapping
spectrophotometers Atmosphere based: Helium balloon creates ozone
profile as altitude increases.
Montreal protocol 1970s realised depletion in ozone layer
Worldwide determination to eradicate threat to ozone Phasing out
CFCs, and developing HFCs and HCFCs HCFCs contains H, C, Cl, and F
H means it is more unstable removed from troposphere before
reaching ozone in stratosphere HFCs contain H, F, and C atoms
cannot form bromine or chlorine radicals but these are greenhouse
gases
WATER
Turbidity: amount of suspended solids, transparency of water-
Ideal drinking water
