1. Explain how to balace the following chemical equation
   Fe₂O₃ + Al →  Fe + Al₂O₃                                                                              (AS 1) 4 Marks
                    (or)
Iron oxide reacts with Aluminium to form Iron and Aluminium trioxide. Write the chemical equation to show the reaction and balance it.

2. Explain how to balance the following chemical equation.
    Na + H₂O → NaOH + H₂                                                                               (AS 1) 4 Marks

3. Balance the following chemical equations by mentioning their physical states.
i) AgCl →  Ag + Cl₂
ii) C₃H₈ + O₂ →  H₂O + CO₂
iii) Na₂CO₃ + HCl →  NaCl + H₂O + CO₂
iv) NaCl + H₂O →  NaOH + Cl₂ + H₂                                                               (AS 1) 4 Marks

4. Write the balanced chemical equations for the following reactions.
i) Sodium + water →  Sodium hydroxide + Hydrogen
ii) Calcium hydroxide + Carbondioxide →  Calcium carbonate + water
iii) Calcium carbonate + Hydrochloric acid →  Calcium chloride + Carbondioxide + water
iv) Ammonia + Chlorine →  Ammonium chloride + Nitrogen                       (AS 1) 4 Marks

5. When solution 'X' is added to Barium chloride solution a white precipitate is formed?
i) Predict the solution 'X' and write its formula.
ii) What is the white coloured precipitate and write its formula.
iii) Write a balanced chemical equation for the above reaction mentioning the physical states.                                                                                                                         (AS 1) 4 Marks

6. Write down the chemical equation for the reaction of burning of Carbon in the presence of Oxygen. Calculate the weight of Carbondioxide formed when 24 grams of Carbon is burnt in air (atomic masses of Carbon and Oxygen are 12 and 16 respectively).        (AS 1) 4 Marks

7. What information could be obtained from the following equations? 


8. Write the following chemical reactions including the physical states of the substances and balance the chemical equations.
i) Zinc reacts with Hydrochloric acid to give Zinc chloride and Hydrogen.
ii) Hydrogen and Oxygen react at very height temperature to give rise to water. (AS 1) 4 Marks

9. Explain the process in which Hydrochloric acid reacts with Zinc experimentally.    (AS 3) 2 Marks

10. Calculate the volume of Oxygen gas needed for the combustion of 200 ml of Ethane. Ethane is a hydrocarbon with the molecular formula C₂H₆.                                (AS 1) 2 Marks

11. Balance the following chemical equations by mentioning their physical states.
^{i) H₂O + CO₂  C₆H₁₂O₆ + O₂}
ii) NaCl + H₂SO₄ →  HCl + Na₂SO₄                                                                   (AS 1) 2 Marks

12. Balance the following chemical equations.                                                         (AS 1) 2 Marks
i) NH₃ + O₂ →  NO + H₂O
ii) Al₂O₃ + HCl →  AlCl₃ + H₂O

13. Balance the following chemical equations.                                                         (AS 1) 2 Marks
i) As + H₂SO₄ →  H₃AsO₄ + SO₂ + H₂O
ii) FeSO₄ + H₂SO₄ →  Fe₂(SO₄)₃ + H₂O + SO₂

14. Cu₂S + O₂ →  Cu₂O + SO₂ Balance the equation.                                         (AS1) 1 Mark

15. TiCl₄ + Na  Ti + NaCl Balance the equation                                               (AS1)1 Mark

16. Cr₂O₃ + Al →  Cr + Al₂O₃ Balance the equation                                             (AS1) 1 Mark

17. HgS + O₂ →  HgO + SO₂ Balance the equation.                                               (AS1) 1 Mark

18. Fe₂O₃ + Al →  Fe + Al₂O₃ Balance the equation.                                           (AS1) 1 Mark

19. PbS + O₂ →  PbO + SO₂ Balance the equation.                                               (AS1) 1 Mark

20. Fe₂O₃ + CO →  Fe + CO₂ Balance the equation.                                           (AS1) 1 Mark