(a) Convert into mole : (i) 12 g of oxygen gas. (ii) 22 g of carbon dioxide. (b) Write the names of the compounds represented by the following formulae : (i) NaBr (ii) Al2O3 (in) ZnNO3 (iv) HCl (v) NaCl (vi) CaCO3

CBSE Class 9 CBSE Class 9 Science
1

(a) (i) 32 g = 1 mole
12g = 1/(2x16) x 12
= 0.375 mole

(ii) 44 g = 1 mole
22 g = 1/44 x 22=1/2mole

(b) (i) Sodium bromide
(ii) Aluminium oxide
(iii) Zinc nitrate
(iv) Hydrogen chloride
(v) Sodium chloride
(vi) Calcium carbonate