1. Which of the following matter fall(s) in the category of substance?
(i) Ice (ii) Milk (iii) Iron (iv) Air (v) Water (vi) Hydrochloric acid

2. Which one of the following is solution?
(i) Mercury (ii) Air (iii) Coal (iv) Milk

3. Give one evidence of modern technology which supports Dalton’s atomic theory.

4. Write formula of the following compounds
(i) Ferric phosphate
(ii) Barium chloride (v) Magnesium sulphate
(iii) Calcium carbonate (vi) Sodium phosphate
(iv) Phosphorous tribromide (vii) Sulphur trioxide

5. Write differences between an atom and a molecule.

6. Write empirical formulae of the following molecules:
C2H4, HCl, HNO3

7. Sulphur is a non-metallic element. How many atoms are present in 16.3 g of S?

8. Molar mass of silver is 107.9 g. What is the mass of one atom of silver?

9. Balance the following equations.
(i) H3PO3 -> H3PO4 + PH3
(ii) Ca + H2O -> Ca(OH)2 + H2
(iii) C3H8 + O2 -> CO2 + H2O

10. Name the following compounds.
Na2O, Cu2Cl2, BaO, Na2SO4