CLASS 7, 8 AND 9_ FORMULA WRITING

FORMULA WRITING 

1.      Write the chemical formula of the following:

i.        Sodium oxide

ii.      Potassium sulphate

iii.    Zinc nitrate

iv.    Ferrous sulphate

v.      Ferric chloride

vi.    Ammonium carbonate

vii.      Calcium bicarbonate

viii.   Cupric sulphide

ix.   Lead(II) nitrate

x.          Aluminium phosphate

2.      An element Y shows variable valency of +2 and +3. Write the formula of its:

i.                    Nitrite

ii.                  Nitride

iii.                Bisulphide

iv.                Oxide

v.                  Zincate

vi.                Permanganate

vii.              Dichromate

viii.            Acetate

ix.                Sulphide

x.                  Bromide

3.      Write down the number of atoms of each kind present in the following molecules:

i.                    H₂S

ii.                  CCl₄

iii.                H₃PO₄

iv.                ZnS

v.                  Ca₃PO₄

vi.                (NH₄)₂SO₄

vii.              Mg(NO₃)₂

viii.            Al₂(SO₄)₃

ix.                CH₃COOH

4.      The formula of nitrate of a metal Z is Z(NO₃)₄. Write the formula of its:

i. Sulphate   ii. Sulphite       iii. Fluoride      iv. Chlorate     v. Carbide

5.       Write the name of the following compounds:

i. HNO₃      ii. H₂SO₄          iii. K₂SO₄           iv. CuCO₃       v. Cu₂S

vi. HgS        vii. AgCl        viii. Al₂O₃            ix.PtCl₄            x. PbO

6.      What do the following symbols stand for:

i.      H            ii. 2O               iii. N₂                iv. [H]

7.      What do the following formula stand for:

i.   CO₂          ii. 5NH₃           iii. 4H₂O          iv. 3NO₃^-

   8.      Identify the basic and acidic radical in these compounds:

                         i.      Potassium nitrate               vi. Ammonium Carbide

                              ii.  Calcium bicarbonate        vii. Zinc sulphate

                            iii.  Ferrous chloride               viii. Calcium Chlorate

iv. Cupric sulphide                ix. Barium Fluoride

               v. Calcium Silicate               x.Ferric Sulphite

9.      What is the ratio of the number of atoms of oxygen to number of atoms of carbon in the following:

i.        C₆H₆O₂

ii.        4Mg(HCO₃)₂

iii.      5C₂H₅OH

iv.      CH₃COOH

v.        Na₂CO₃. 10H₂0