5. Chemistry Inorganic
Organic
Physics
Physical
Biology
Analytical
Science Geology Bio
Polymer
Medicine
Industrial
Materials Nano
Pharmacy

11. Atom Molecule
Indivisible Can split in to
components
Smallest particle of an Smallest particle of a
element compound
It may or may not exist It can exist in the free
in the free state state
Atoms take part in During chemical
chemical reaction reaction molecules
split in to atoms.

12. Monovalent F-, Cl-, Br-, I-, NO3-, CN-, HCO3-
, CH3COO-
Acid radicals
Divalent Acid O2-, S2-, SO42-, CO32-, Cr2O72-,
MnO42-, SiO32-, ZnO22-, SnO32-
radicals
Trivalent Acid PO43-, [Fe(CN)6]3-
radicals
Tetravalent [Fe(CN)6]4-
Acid radicals

14. 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

15. 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.

16. 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

17. Calculate the Molecular weight from the molecular formulae
CaCO3 40+12+16x3 = 100
H2SO4 1x2+32+16x4 = 98
CuSO4 63.5+32+16x4 =
CuSO4.5H2O 63.5+32+16x4+18x5 =
H 2 C 2 O4 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 =

19. A chemical equation is a method
of expressing a chemical reaction
with the help of formulae, of
reactants and products.
HCl + NaOH NaCl + H2O

20. Na2CO3 + HCl NaCl + H2O +CO2
Na2CO3 + HCl 2NaCl + H2O +CO2
Na2CO3 +2HCl 2NaCl + H2O+CO2

21. Al2O3 + NaOH Na3AlO3 + H2O
Al2O3 + NaOH 2Na3AlO3 + H2O
Al2O3 + 6NaOH 2Na3AlO3 + H2O
Al2O3 + 6NaOH 2Na3AlO3 + 3H2O