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

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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