LANGUAGE OF CHEMISTRY

Symbols and Formulae

Some typical symbols derived from Latin names:

English name	Latin name	Symbol
Sodium	Natrium	Na
Potassium	Kalium	K
Iron	Ferrum	Fe
Copper	Cuprum	Cu
Silver	Argentum	Ag
Gold	Aurum	Au
Tin	Stannum	Sn
Mercury	Hydrargyrum	Hg
Lead	Plumbum	Pb
Antimony	Stibium	Sb

→ German name of Tungsten is Wolfram & its symbol is W.
→ The term Atom was first used by Dalton in his atomic theory.
→ The term Molecule was first used by Avogadro in his ‘Avogadro’s hypothesis.
→ Dalton used the term compound atom instead of molecule.
→ Atom is the smallest particle that takes part in a chemical reaction.

Elements and Compounds
→ There are 92 natural elements and more than 31 artificial elements.
→ The compound is composed of elements in a fixed proportion.
→ A substance composed of two or more non-reacting compounds is a mixture.

Some Methods for the Separation of Mixture:

→ Filtration: used for separating an insoluble solid present in a liquid; e.g. BaSO₄ present in aqueous solution, CaCO₃ in water etc.

→ Distillation is used for purifying liquids that boil without decomposing.
→ Distillation is the best method for the separation of a 1:1 mixture of ortho and para nitrophenol; Ethyl alcohol & ether.
→ Absolute alcohol is prepared by azeotropic distillation.
→ Sublimation: Used for separating two solids eg. NH₄Cl, I₂, + sand, etc where one of the two solids is volatile.
→ Substance undergoing sublimation: NH₄Cl, I₂, dry ice (solid CO₂), naphthalene, benzoic acid, salicylic acid, corrosive sublimate (HgCl₂), camphor, arsenic oxide, red phosphorus (in vacuum) etc.

→ Fractional distillation: applied if the boiling point of two liquids differ by 15–20°C eg: Benzene & toluene; methyl alcohol & acetone [BPKIHS 2003]
→ Distillation under reduced pressure or vacuum: Used for separating liquid that decomposes at boiling point. Eg. H₂O₂ glycerol [MOE 1997]

→ Steam distillation: Used for separating water-insoluble liquid from a mixture of two liquids by heating with water eg. Nitrobenzene, aniline, lemon oil, sandalwood oil etc.
→ Crystallization: Used to separate dissolved crystalline solid from its solution eg. CuSO₄ crystals from its aqueous solution.
→ Fractional crystallization: Used to separate two solutions that differ in solubility e.g.: KCl + KClO₃ (less soluble), Na₂Cr₂O7 + Na₂SO₄ (less soluble)

→ Solvent extraction: Used to separate two solids by means of a solvent. E.g. Sand + saltwater (used as solvent); I₂ + water (chloroform used as solvent)

→ Mechanical separation: Separating two immiscible liquids with help of a separating funnel. Eg. Oil in water.
→ Magnetic method: For iron filling + sand; tinstone + wolframite. Here, one of the solids should be magnetic and the other should be non-magnetic.
→ Atmolysis: Used form mixture of gases or vapours based on the difference of rate of diffusion e.g. H₂ + O₂

Chromatography:
→ Latest technique to purify organic compounds [MOE 98]
→ Discovered by Tswet
→ Mobile/Moving phase – liquid or gas
→ Stationary/fixed phase – liquid or solid absorbed in solid
→ Suitable absorbents used in fixed phase: Alumina (Al₂O₃), Silica gel (SiO₂), MgO/fuller’s earth.

→ Based on selective adsorption [IOM 1999, 1996]
→ In paper chromatography, the mobile phase is liquid and stationary in solid [IOM 1997]
→ Moisture is removed from substances by desiccation [IOM 2000]
→ A mixture of sand and powdered charcoal can be separated by washing [IOM 2000]

→ Isomorphs: molecules having the same number of atoms bonded in a similar fashion. E.g.
i. FeSO₄.7H₂O, MgSO₄.7H₂O and ZnSO₄. 7H₂O

ii. K₂SO₄, K₂CrO₄ & K₂SeO₄

iii. Alums: Ammonium alum [(NH₄)₂SO₄.Al₂(SO₄)₃.24H₂O] and Potash alum [K₂SO₄, Al₂(SO4)₃.24H₂O]

→ Isobars: atoms having the same mass number but different atomic numbers. E.g. ₁₈Ar⁴⁰, ₁₉K⁴⁰ & ₂₀Ca⁴⁰ are isobars.
→ Isobars have the same number of nucleons. [MOE 2055]
→ Isotopes: atoms having the same atomic no but different mass no. E.g. ₁H¹, ₁H², ₁H³
→ 1 𝞪–decay followed by 2 β– decay produces an isotope of the parent atom.
→ Isotones: atoms having the same number of neutrons but different mass no E.g ₁₄Si³⁰, ₁₅P³¹, ₁₆S³², @ Isotone = same no. of neutrons

→ Isomers: atoms having the same atomic number & mass number but different radioactive properties E.g. ₃₅Br⁸⁰
→ γ-decay produces isomer with parent atom
→ Isodiaphers: atoms having the same difference of neutron & proton (h–p)
→ 𝛼-decay produces isodiaphers of with parent atom.
→ Isoelectronic atoms or groups of atoms having the same no of electrons e.g. CO, CN⁻, NO⁺ are isoelectronic

→  Isoatomic: Having same no of atom e.g. N₂O & SO₂

→ Isosters: Isoelectronic + isoatomic e.g. N₂O & CO₂

→ Isolobal: atoms having the same geometry & hybridization e.g. (SO₂, SnCl₂)

→ An element has mass number 14 & number of neutron 8, then it is an Isotope of carbon. [MOE 2002]

Also, Read our other Notes of Physical Chemistry:

1. Language of Chemistry
2. Laws of Stoichiometry & Avogadro's Hypothesis
3. States of Matter: Gaseous State
4. States of Matter: Liquid State & Colligative Properties
5. States of Matter: Solid State
6. Colloidal Chemistry
7. Atomic Structure
8. Chemical Bonding
9. Oxidation & Reduction
10. Periodic Table
11. Volumetric Analysis
12. Ionic Equilibrium
13. Acids, Bases & Salts
14. Chemical Kinematics
15. Electrochemistry
16. Thermodynamics
17. Chemical Equilibrium