Formula And Equations

THE WORLD OF CHEMISTRY IS SO WIDE AND

WONDERFUL

Chemistry is from the Greek Word meaning

“ Cast together” or “Pour together”.

CHEMISTRY IS THE STUDY OF COMPOSITION, STRUCTURE AND PROPERTIES OF MATTER AND THE CHANGES IT UNDERGOES.

ScienceChemistryInorganic

Organic

Physical

Analytical

Bio

Polymer

Industrial

Nano

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Matter: Anything that occupies space and has mass. Matter can exist in solid, liquid and gaseous states.

Wood, Stone, Air, Water

Elements: These are pure substances that cannot be decomposed into simpler substances by chemical methods.

Hydrogen, Oxygen, Sulphur, Gold

Compounds: Substances formed by the union of two or more elements in a definite ratio.

Water, Sodium chloride, sugar

Atoms: The smallest particle of an element which cannot be divided by chemical methods.

H, He, Li, B

Molecule: Smallest particle of an element or a compound which can exist in the free state.

H2, O2, N2

Atom Molecule

Indivisible Can split in to components

Smallest particle of an element

Smallest particle of a compound

It may or may not exist in the free state

It can exist in the free state

Atoms take part in chemical reaction

During chemical reaction molecules split in to atoms.

Monovalent Acid radicals

F-, Cl-, Br-, I-, NO3-, CN-, HCO3

-, CH3COO-

Divalent Acid radicals

O2-, S2-, SO42-, CO3

2-, Cr2O72-,

MnO42-, SiO3

2-, ZnO22-, SnO3

2-

Trivalent Acid radicals

PO43-, [Fe(CN)6]3-

Tetravalent Acid radicals

[Fe(CN)6]4-

Writing Formulae of Compounds Containing

Positive and Negetive Radicals

1 Write down the symbols or formulae of two radicals (A & B) side by side, positive A on the left and negative B on the right side.

A = Al B = Cl Al Cl

2 Write their valences at the top

Al3 Cl1

3 Cross the valences.

Al3 Cl1 = AlCl3

4 Complex radicals are enclosed in brackets.

(NH4)2SO4

Molecular Formula of a compound is a symbolic representation of a molecule of the compound.

Molecular Formula Indicates;a) Actual number of atoms of the

elements in a molecule of the compound.

b) The molar mass of the substance.

Molecular Formula of Water is H2O

This indicates one molecule of water contains two hydrogen atoms and one oxygen atom.

Molar mass of H2O is , 1x2 + 16 = 18 g mole-1

CaCO3 40+12+16x3 = 100

H2SO4 1x2+32+16x4 = 98

CuSO4 63.5+32+16x4 =

CuSO4.5H2O 63.5+32+16x4+18x5 =

H2C2O4 1x2+12x2+16x4 =

Na2CO3 23x2+12+16x3 =

FeSO4 55.8+32+16x4 =

KOH

NaOH 23+16+1 =

HCl 1+35.6 =

CaCO3 40+12+16x3 +

HNO3 1+14+16x3 =

(NH4)2CO3 (14+1x4)x2+12+16x3 =

C12H22O11 12x12+1x22+16x11 =

Calculate the Molecular weight from the molecular formulae

Chemical Equations

A chemical equation is a method of expressing a chemical reaction with the help of formulae, of reactants and products.

HCl + NaOH NaCl + H2O

Na2CO3 + HCl NaCl + H2O +CO2

Na2CO3 + HCl 2NaCl + H2O +CO2

Na2CO3 +2HCl 2NaCl + H2O+CO2

Al2O3 + NaOH Na3AlO3 + H2O

Al2O3 + NaOH 2Na3AlO3 + H2O

Al2O3 + 6NaOH 2Na3AlO3 + H2O

Al2O3 + 6NaOH 2Na3AlO3 + 3H2O

Thank You