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Contents Mathematics Fermat Physics Wordlist Notes Chemistry Quick Facts Reference LINKS

Relative Atomic Mass and Relative Molecular Mass: Some Common Substances
HydrogenH22HH = 12 x 1 =2
NitrogenN22NN = 142 x 14 =28
WaterH2O2H + 1OH = 1, O = 162 x 1 + 1 x 16 =18
Sodium chlorideNaCl1Na + 1ClNa = 23, Cl = 35.51 x 23 + 1 x 35.5 =58.5
AmmoniaNH31N + 3HN = 14, H = 11 x 14 + 3 x 1 =17
Magnesium nitrateMg(NO3)21Mg + 2N + 6OMg = 24, N = 14, O = 161 x 24 + 2 x 14 + 6 x 16 =148

Other elements that exist as molecules:

Chlorine: Cl2
Flourine: F2
Oxygen: O2
Iodine: I2
Sulphur: S8
Phosphorus: P4

Miscellaneous Compounds:

Strontium nitrate: Sr + 2NO3 = Sr (NO3)2
Strontium sulphate: Sr + SO4 = Sr SO4
Ammonium sulphate: 2(NH4) + SO4 = (NH4)2 SO4
Hydrated iron sulphate: Fe + SO4 + 7H2O = Fe SO4.7H2O
Iron (III) ammonium sulphate: NH4 + Fe + (SO4)2
Calcium oxide: Ca + O = Ca O
Aluminium chloride: Al + Cl3 = Al Cl3
Silicon dioxide: Si + O2 = Si O2

Common acids:
Hydrochloric acid: H CL; Sulphuric acid: H2 SO4; Nitric acid: HNO3;Ethanoic acid: CH3 COOH; Methanoic acid; Carbonic acid; citric acid; tannic acid.
Acids usually react with metals giving off hydrogen and the metal's salt.The metal drives out the hydrogen ions from the acid, e.g.

Mg + H2 SO4 = Mg SO4 + H2

The more hydrogen ions in the acid, the stronger it is in solution. Strong acids and alkalis can burn on contact. Examples of resultant metal salts are sulphates such as magnesium sulphate above, chlorides or nitrates. The hygrogen ions are positive: H + ions.

Alkaline solutions contain negative hydroxide ions: OH - ions which neutralise acids by drawing off the H+ ions. The neutralisation gives off water, e.g.

HCl + Na OH = Na Cl + H2O and the reaction between the ions:
H + + OH - = H2O

All bases neutralise acids. Bases include metal oxides, metal hydroxides, metal carbonates, metal hydrogen carbonates and ammonia solution.

The pH Scale:
Going from 0 to 14: 0 to 7 acidic in decreasing strength; 7 = neutral; 7 to 14 increasing alkalinity.

Common alkalis:
Sodium hydroxide: Na OH Potassium hydroxide: K OH; Calcium hydroxide: Ca (OH)2; Ammonia: NH3

Acids turn litmus red; alkalis turn litmus blue, and neutrals leave litmus unchanged. Phenolphthalene is turned pink by alkaline solutions and remains unchanged by acids or neutrals.

Common salts:
Sodium chloride: Na Cl, calcium carbonate: Ca CO3, potassium chloride: K Cl, barium sulphate: Ba SO4, cobalt chloride: COCL2.6H2O, zinc chloride: ZnCl2.6H2O, copper (II) sulphate: CuSO4.5H2O, sodium carbonate: Na2CO3.10H2O, ammonium nitrate: NH4 NO3, barium carbonate: Ba CO3, barium chloride: Ba Cl2, sodium citrate, ammonium carbonate, lead nitrate, lead sulphate, silver chloride and sodium carbonate.

Contents Mathematics Fermat Physics Wordlist Notes Chemistry Quick Facts Reference LINKS


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