Important Chemical Reactions

Metal → Hydroxide / Acid Reactions

(1) Sulfur → Sulfuric acid

S + O2 → SO2

2SO2 + O2 → 2SO3

SO3 + H2O → H2SO4

(2) Calcium → Calcium hydroxide

2Ca + O2 → 2CaO

CaO + H2O → Ca(OH)2

(3) Nitrogen → HNO3 & HNO2

N2 + O2 → 2NO

2NO + O2 → 2NO2

2NO2 + H2O → HNO2 + HNO3

(4) Nitrogen → NH4OH

N2 + 3H2 → 2NH3 (catalyst)

NH3 + H2O → NH4OH

(5) Sodium → Sodium hydroxide

2Na + 2H2O → 2NaOH + H2

4Na + O2 → 2Na2O

Na2O + H2O → 2NaOH

(6) Iron → Fe(OH)3

Fe + Cl2 → FeCl3

FeCl3 + 3H2O → Fe(OH)3 + 3HCl

(7) Iron → Fe(OH)2

Fe + 2HCl → FeCl2

FeCl2 + 2H2O → Fe(OH)2 + 2HCl

(8) Copper → CuSO4

Cu + H2SO4(conc) → CuSO4 + 2H2O + SO2

Chemical reaction to distinguish between Mixture and Comound

Distinction Test

Fe + S + 2HCl → FeCl2 + S + H2 (blue‐flame pop)

FeS + 2HCl → FeCl2 + H2S (rotten‐smell gas)

Important reactions for the preparation of Oxygen (O2)

Decomposition reactions

Decomposition of red Mercuric oxide

2HgO → 2Hg + O2

Decomposition of hydrogen peroxide

2H2O2 → 2H2O + O2

Decomposition of potassium chlorate

2KClO3 → 2KCl + 3O2

Decomposition of silver(I) oxide

2Ag2O → 4Ag + O2

Decomposition of lead oxide

2Pb3O4 → 6PbO2

Red Litharge

2PbO2 → 2PbO + O2

Catalytic nature of water

4Fe + 3O2 → 2Fe2O3

H2O → H2 + ½O2

4P + 5SO2 → 2P2O5 + 5S

Combustion reactions

General Hydrocarbon Combustion - Easy way of balancing a combustion reaction of Hydrocarbons.

CxH2y + (x + y/2)O2 → xCO2 + yH2O

CH4

CH4 + 2O2 → CO2 + 2H2O

C2H6

C2H6 + 7/2O2 → 2CO2 + 3H2O

C10H20

C10H20 + 15O2 → 10CO2 + 10H2O

C6H14

C6H14 + 19/2O2 → 6CO2 + 7H2O

C2H2

C2H2 + 5/2O2 → 2CO2 + H2O

Oxidation of Iron or combustion of iron

4Fe + 3O2 → 2Fe2O3

Oxidation of glucose or burning of food

C6H12O6 + 6O2 → 6CO2 + 6H2O + heat

Reaction of oxygen with nitric oxide

2NO + O2 → 2NO2

Reaction of Magnesium to form magnesium oxide

2Mg + O2 → 2MgO

Formation of Sulfur trioxide or combustion of sulfur trioxide

2SO2 + O2 → 2SO3

Oxidation of Ammonia

4NH3 + 3O2 → 2NO2 + 6H2O

Oxidation of Aluminium

4Al + 3O2 → 2Al2O3 (white)

Combustion or oxidation of H2S

2H2S + 3O2 → 2SO2 + 2H2O

Oxidation of Zinc

2Zn + O2 → 2ZnO

Oxidation of Carbon disulfide

CS2 + 3O2 → CO2 + 2SO2

Oxidation of lead

Pb + O2 → 2PbO (Yellow)

Oxidation of Zinc sulfide

2ZnS + 3O2 → 2ZnO + 2SO2

Oxidation of copper

Cu + O2 → 2CuO (black)

Oxidation of mercury

2Hg + O2 → 2HgO (red)

Example of hydrated Compounds with Common names and Formulae

Barium chloride dihydrate

BaCl2·2H2O

Calcium sulphate dihydrate (Gypsum)

CaSO4·2H2O

Copper nitrate trihydrate

Cu(NO3)2·3H2O

Copper II chloride tetrahydrate

CuCl2·4H2O

Copper II sulphate pentahydrate (Blue vitriol)

CuSO4·5H2O

Calcium chloride hexahydrate

CaCl2·6H2O

Iron (II) sulphate heptahydrate (Green vitriol)

FeSO4·7H2O

Zinc sulphate heptahydrate (White vitriol)

ZnSO4·7H2O

Magnesium sulphate heptahydrate (Epsom salt)

MgSO4·7H2O

Sodium carbonate decahydrate (Washing soda)

Na2CO3·10H2O

Sodium sulphate decahydrate (Glauber’s salt)

Na2SO4·10H2O

Crystal & Moisture Behavior

Efflorescence

When exposed to air lose their water of crystallization and transformed to powder substance—for example Na2CO3·10H2O.

Deliquescent crystals

When exposed to air lose their water of crystallization and transformed to saturated solutions.

For example CuSO4·5H2O—when exposed to air at ordinary temperature it absorbs water from air and becomes a saturated solution.

Hygroscopic Substances

Absorb moisture without dissolving in water.

Examples: CaCl2·6H2O, MgCl2·6H2O, NaOH, KOH, ZnCl2, Zn(NO3)2, Cu(NO3)2.

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List of some Important Solvents

  • Sulfur in CS2
  • Paraffin wax in turpentine
  • Rubber in benzene
  • Iodine in Ethylalcohol
  • Paint in turpentine
  • Niter in water
  • Nail Polish in Acetone
  • Rust in oxalic acid
  • Chlorophyll in Methylated spirit
  • Oil in Petrol

Flame Tests

Arsenic (As)

Blue

Boron (B)

Bright green

Barium (Ba)

Pale/Apple green

Calcium (Ca)

Brick red

Caesium (Cs)

Blue-violet

Copper(I) (Cu I)

Blue

Copper(II) (non-halide)

Green

Copper(II) (halide)

Blue-green

Iron (Fe)

Gold

Indium (In)

Blue

Potassium (K)

Lilac/violet

Lithium (Li)

Pink-red

Magnesium (Mg)

Bright white

Molybdenum (Mo)

Yellowish green

Sodium (Na)

Intense yellow

Phosphorus (P)

Pale bluish green

Lead (Pb)

Blue

Rubidium (Rb)

Red-violet

Antimony (Sb)

Pale green

Selenium (Se)

Azure blue

Strontium (Sr)

Red

Tellurium (Te)

Pale green

Thallium (Tl)

Pure green

Zinc (Zn)

Bluish green

Flames - Common Ionic Compounds

Copper Compound
Copper Compound

Lithium Compound
Lithium Compound

Potassium Compound
Potassium Compound

Sodium Compound
Sodium Compound