Chemistry Important Notes

  Exceptions:

Insoluble	Soluble
Chloride, Bromide, Iodide – Silver, Lead	All halides
All Carbonates	Sodium, Potassium, Ammonium
Sulphates – Calcium, Barium, Lead	All sulphates
	All Nitrates
	Sodium, Potassium, Ammonium all salts

 

Indicator	Acid	Alkali
Litmus Paper	Red	Blue
Methyl Orange	Red	Yellow
Phenolphthalein	Colorless	Pink
Thymolphthalein	Colorless	Blue

 

Acid + Metal à Salt + H₂

Base + Acid à Salt + H₂O

Acid + Carbonate à Salt + H₂O + CO₂

 

Aluminium Extraction

2Al₂O_3(l) à 4Al_(l) + 3O_2(g)

 

Extracting Iron

C_(s) + O_2(g) à CO_2(g)

C_(s) + CO_2(g) à 2CO_(g)

Fe₂O_3(s) + 3CO_(g) à 2Fe_(l) + 3CO_2(g)

CaCO_3(s) à CaO_(s) + CO_2(g)

CaO_(s) + SiO_2(s) à CaSiO_3(s)

 

Substance	Properties	Uses
Diamond	Naturally hard, cut into other substances	Tools drilling, cutting
Graphite	Soft, slippery	Engine, lock lubricant
	Conducts electricity	Electrodes
Silicon (IV) Oxide	Hard, scratch other substances	In sandpaper
	High melting point	Bricks for lining furnaces
Aluminium	Low density, ductile, conducts electricity, resists corrosion	Electricity cables
	Non-toxic, resists heat, malleable	Containers, cans, foil
	Low density, resists corrosion	Aircraft
Copper	Ductile, conduct electricity	Electrical wiring
	Malleable, doesn’t corrode, non-toxic	Water pipes
Zinc	Prevents rust	Coating/ galvanizing iron, steel
	Current produced when connected to the carbon electrode	Torch battery

 

Hydrogen – Oxygen Fuel Cell
Advantages	Disadvantages
-          Harmless product water	-          It is a gas.
-          Made by electrolysis	-          It is obtained from fossil fuels.

 

Petrol Engine
Advantages	Disadvantages
-          Widely available	-          Produces harmful substances
-          Cheap	-          Obtained from oil (non-renewable)

 

Alloy	Elements	Properties	Uses
Brass	Copper, Zinc	Hard, malleable, attractive, doesn’t corrode	Knobs, musical instruments, ornaments
Bronze	Copper, Tin	Hard, resist corrosion, sonorous	Coin, statue, propellers ship, bells
Stainless Steel	Iron, Carbon, Nickel, Chromium	Strong, resist corrosion, attractive	Utensils, cutlery, construction, equipment
Aluminium Alloy	Aluminium, Zinc, Magnesium, Copper	Light, strong, doesn’t corrode	Aircraft, spacecraft

 

Formulas:

Alkane	Alkene	Alcohol	Carboxylic Acid
CnH2n+2	CnH2n	CnH2n+1OH	CnH2n+1COOH

 

Pollutant	Formed	Harm
Carbon dioxide	Complete Combustion	Global warming, climate change
Carbon monoxide	Incomplete Combustion	Haemoglobin in blood prevents oxygen in the body
Sulfur dioxide	Power Station	Acid rain kills river life, attacks stonework
Nitric oxide, Nitrogen dioxide	Motor, Furnaces	Respiratory problems, photochemical smog
Particulate	Incomplete Combustion	Respiratory problems, cancer

 

C1 – C4	Refinery Gas	Bottled gas for cooking and heating
C5 – C6	Gasoline (Petrol)	Fuel for cars
C6 – C10	Naphtha	Feedstock for many chemicals and plastic
C10 – C15	Kerosene (Paraffin)	Fuel for aircraft, oil stoves and lamp
C15 – C20	Diesel Oil (Gas Oil)	Fuel for diesel engines
C20 – C30	Fuel Oil	Fuel for power station, ship, and for home heating system
C30 – C50	Lubricating Fraction	Oil for machinery, waxes, polishes
C50 <	Bitumen	Road surfaces and roofs

 

Fermentation ( 25-35°C, Yeast catalyst)
Advantages	Disadvantages
-          Renewable	-          High area to grow. The process is slow.
-          Waste plant material can be used.	-          Not pure product.
-          Reaction happens at room temperature.	-          Yeast stops after a certain level of ethanol %.

 

Ethene with steam (300°C, 60-70 atm)
Advantages	Disadvantages
-          Process is fast.	-          Petroleum is a non-renewable source.
-          Runs non-stop.	-          Reaction is reversible.
-          Pure ethanol.	-          High electricity required.

 

Polymer		Examples
HDPE	High Density poly(ethene)	Bowls, chairs, dustbins, artificial joints
LDPE	Low Density poly(ethene)	Plastic bag, disposable gloves, food wrap
PVC	Polychloroethene	Water pipes, wellingtons, hoses, cover for electrical cables.
	Polypropene	Crates, ropes
	Polystyrene	Packaging, roofs, floors, walls, fast food cartons (thermal insulator)
PTFE	Teflon	Frying pan, irons, flooring, nail polish, eye shadow, windscreen wipers
Nylon	Polyamide	Ropes, fishing nets, lines, tents, kites, curtains, umbrella fabric
PET	Polyester	Bottle, container, thread, clothing