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F4 CHEMISTRY
ATMOSPHEREOCEANROCKS & MINERALS
PLANET EARTH (matter)
ATM OSPHERE OCEAN ROCK &M INERAL
EARTH
GASES IN THE AIR COMPOUNDS
IN SEA WATER
COMPOUNDS OF METALS
MATTER (substance)
Gas
Solid
Liquid(solution)
ATMOSPHERE
EARTH
OCEAN
\
THE ATMOSPHERE
Atmosphere
Earth
AIR
AIR (composition) NITROGEN (78%) OXYGEN (21%) NOBLE GASES (1%) CARBON DIOXIDE(0.03-0.04%) WATER VAPOUR OTHERS
AIR (separating gases) Liquefaction of air
AIR (g) → AIR (l) Fractional distillation of liquid air
(Fractionating column)
• Nitrogen (g) (bp=-196oC) AIR (l)
• Oxygen (g) (bp=-183oC)
TEST FOR GASES OXYGEN
RELIGHTS A GLOWING SPLINT NITROGEN
NO SIMPLE TEST CARBON DIOXIDE
TURNS LIME WATER TO MILKY Lime water (calcium hydroxide solution) Milky substance (calcium carbonate)
WORD EQUATION
CARBON DIOXIDE turns LIME WATER to milky
Carbon + Calcium → Calcium + waterdioxide hydroxide carbonate(g) (aq) (s) (l)
TEST FOR GASES (cont.)
CARBON DIOXIDE (excess) MILKY SOLUTION TURNS COLOURLESS Colourless solution (calcium
hydrogencarbonate solution) CHLORINE
Bleaches wet litmus paper
OCEAN OCEAN - SEA WATER SEA WATER - AQUEOUS SOLUTION SEA WATER CONTAINS
WATER (96.5%) DISSOLVED SALTS (2.5%)
• Mostly common salt (sodium chloride) OTHERS(includes dissolved gases)
(1%)
Obtain common salt from Sea water
FILTRATION RESIDUE – mud, sand, solid particles FILTRATE – sea water
EVAPORATION of the filtrate Dilute solution → Concentrated solution
→ Saturated solution
CRYSTALLIZATION Cool slowly – to obtain large crystals of
Salt (NaCl) Filtration – to obtain Salt
Obtain pure water from Sea water
DISTILLATION Boiling
Water (l) → Water (g)(water vapour)
Condensing• Water (g) → Water (l)
(water vapour) Distillate
- pure water / distilled water
TEST FOR COMMON SALT SALT IS AN IONIC COMPOUND
CATION (from metals) Test – FLAME TEST
ANION (from non-metals) Test – Chemical Test
FLAME TEST FOR CATIONS Nichrome wire Concentrated hydrochloric acid Bunsen burner Colour of flame
Potassium compound Sodium compound Calcium compound
TEST FOR ANION (chloride) Silver nitrate solution & dilute nitric
acid Add to a solution of chloride White precipitate appear
White precipitate is SILVER CHLORIDE Word equation:
TEST FOR ANION (sulphate) Barium chloride solution & dilute
hydrochloric acid Add to a solution of sulphate White precipitate appear
White precipitate is BARIUM SULPHATE Word equation:
TEST FOR ANION (carbonate)
Dilute hydrochloric acid Add to a solution of carbonate Effervescence
Colourless gas is CARBON DIOXIDE Word equation:
TEST FOR WATER Dry cobalt(II) chloride paper (blue) Water turns blue cobalt(II) chloride
paper pink.
ELEMENTS OF WATER COMPOUND → ELEMENTS Word equation
WATER → OXYGEN + HYDROGEN(Compound) (Elements of water)
ELECTRICITY is required SOURCE OF ELECTRICITY (CELL) POSITIVE ELECTRODE (+) NEGATIVE ELECTRODE (-)
The process is ELECTROLYSIS OF WATER
Dissolved salts in Sea water Dissolved salts
Sodium chloride (NaCl) Magnesium chloride (MgCl2)
Potassium sulphate (K2SO4)
Calcium chloride (CaCl2)
Dissolved ions (Dissolved ions of Na+, Cl-, Mg2+, SO4
2-, K+, Ca2+)
Electrolysis of Sea water Sea water is a mixture
Water + dissolved Salts Substances from electrolysis of sea
water using carbon electrodes: Hydrogen (at the negative electrode) Chlorine (at the positive electrode) Sodium hydroxide (in the solution)
EARTH’S CRUST (Minerals)
ROCK is a mixture of MINERALS
MINERALS
Compounds Elements
Compounds of metals
Compounds of non-metals
Al2O3
CaCO3
SiO2
Gold
Silver
ORES ORE
Rock containing compounds of metals Examples of Ore
Bauxite (aluminium ore) Haematite (iron ore) Cinnabar (mercury ore)
EXTRACTION OF METALS FROM ORES
Physical separation Heating of ore Heating the ore with carbon Electrolysis of molten ore
CHALK, LIMESTONE, MARBLE
Calcium carbonate exists in 3 forms: Chalk Limestone Marble
Formation of chalk Skeleton or shells of dead sea animals High pressure or temperature Long time
Investigating Calcium carbonate
Action of heat Calcium Calcium + carbon carbonate oxide dioxide
Action of dilute hydrochloric acid Effervescence Calcium chloride, carbon dioxide, water
Action of water Insoluble in water
LIMESTONE and related compounds
LIMESTONE Calcium carbonate ( formula)
QUICKLIME Calcium oxide ( formula)
SLAKED LIME Calcium hydroxide ( formula)
LIMEWATER Saturated solution of calcium hydroxide
(formula )
Further reactions Calcium oxide reacts with water to form
calcium hydroxide Calcium hydroxide is slightly soluble in
water Limewater is a saturated solution of
calcium hydroxide Limewater can be used to test for carbon
dioxide gas (The milky substance is calcium carbonate)
EROSION Erosion is a complicated process
Broken down into smaller pieces Changed into other material Lost of surface material
Causes of erosion Heat Rain (acid rain) Wind, running water, gravity
FORMATION OF LIMESTONE CAVES Heat decomposes limestone
forms calcium oxide and carbon dioxide Acid rain reacts with limestone
forms salt and carbon dioxide (carbon dioxide dissolves in rain
water to form carbonic acid) Limestone is slightly soluble in water
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