What do the following formulae stand for : (i) 2O (ii) O2 (iii) O3 (iv) H2O (b) Give the chemical formulae of the following compounds : (i) Potassium carbonate (ii) Calcium chloride (c) Calculate the formula unit mass of Al2(SO4)3

CBSE Class 9 CBSE Class 9 Science
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What do the following formulae stand for : (i) 2O (ii) O2 (iii) O3 (iv) H2O (b) Give the chemical formulae of the following compounds : (i) Potassium carbonate (ii) Calcium chloride © Calculate the formula unit mass of Al2(SO4)3
(Given atomic mass of Al = 27u, S = 32u, O = 16u)

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(a) (i) Two atoms of oxygen —> 2O
(ii) Diatomic oxygen -» O2 molecule
(iii) Triatomic oxgyen —> O3 molecule
(iv) Two atoms of hydrogen and 1 atom of oxygen forming one molecule of water.
(b) K2CO3 - Potassium carbonate CaCl2 - Calcium chloride
© Al2(SO4)3
Al - 27 x 2 = 54u
S - 32 x 3 = 96u
Q - 16 x 12 = 192u
Formula unit mass=342 u.