Page 68 - Chemistry ICSE Class IX

56 ICSE Chemistry – 9
35. Name the gases consumed and/or produced during the following processes:
(a) Photosynthesis
(b) Combustion of coal
(c) Respiration
36. Draw a owsheet diagram describing the oxygen cycle in nature.
37. Why is carbon dioxide produced during respiration by humans and animals?
38. Draw the owsheet diagram of the carbon dioxide cycle in the nature.
39. How is atmospheric carbon dioxide xed by ocean/ sea water?

40. Classify the following reactions on the basis of their type:
(a) Lead nitrate on heating decomposes to give lead oxide, nitrogen dioxide and oxygen.
(b) Potassium chlorate on heating decomposes to give potassium chloride and oxygen gas.
(c) Methane (CH ) burns in air to give carbon dioxide, water and heat is evolved.
4
(d) White precipitate of silver chloride is formed on adding a solution of sodium chloride to silver nitrate
solution.
(e) The colour of potassium permanganate gets decolourised when added to an acidi ed solution of ferrous
sulphate.
(f) Phosphorus reacts with chlorine to give phosphorus pentachloride.
(g) Sulphur trioxide reacts with water to give sulphuric acid.
(h) Magnesium burns in carbon dioxide to form magnesium oxide and carbon.
41. What is the difference between combination and decomposition reactions? Write an equation for each type.
42. Classify each of the following reactions as combination, decomposition, displacement or double displacement
reactions:
(a) 2KNO (s) o 2KNO (s) + O (g)
3
2
2
(b) Zn(s) + 2AgNO (aq) o Zn(NO ) (aq) + 2Ag(s)
3 2
3
(c) Ni(NO ) (aq) + 2NaOH(aq) o Ni(OH) (p) + 2NaNO (aq)
3
2
3 2
(d) Zn(s) + 2HCl(aq) o ZnCl (aq) + H (g)
2
2
(e) 2CuO(s) o 2Cu(s) + O (g)
2
(f) Cl (g) + 2NaBr(aq) o Br 2 + 2NaCl(aq)
2
(g) MgO(s) + C(s) o CO(g) + Mg(s)
(h) 2KClO (s) o 2KCl(s) + 3O (g)
2
3
43. Write balanced equations for the following reactions and identify the type of reaction:
heat
(a) Zinc carbonate(s) o Zinc oxide(s) + Carbon dioxide(g)
(b) Magnesium(s) + Hydrochloric acid(aq) o Magnesium chloride(aq) + Hydrogen(g)
(c) Potassium bromide(aq) + Barium iodide(aq) o Potassium iodide(aq) + Barium bromide(aq)
(d) Hydrogen(g) + Chlorine(g) o Hydrogen chloride(g)
44. Why should magnesium ribbon be cleaned before burning in air?
45. Why does colour of copper sulphate solution change when an iron nail is dipped into it?
46. Tick (9) the correct answer.
(i) Which of the following involves both physical and chemical changes?
(a) ripening of fruit ‰ (b) burning of a candle ‰
(c) melting of wax ‰ (d) crystallisation of a substance ‰