CBSE Guess > Papers > Important Questions > Class IX > 2009 > Science > Science By : Mr M. p. Keshri
CBSE CLASS I X
Atoms And Molecules (Solved)
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Q. 33. Some molecules are given below. Differentiate between them :
(i) chlorine molecule
(ii)0 Argon molecule
(iii) Sulphuric acid molecule
(iv) Hydrogen chloride molecule
(v) Hydrogen molecule
(vi) nitrogen molecule
(vii) Neon molecule.
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Q. 34. What is atomicity of an element ? Give examples of mono, dia and triatomic molecules.
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Q. 35.State the basic unit of all material substances.
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Q. 36. State molecules containing more than four atoms. What is its name ?
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Q. 37. State the ultimate particle on which properties of a material depends.
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Q. 38. Choose and explain the correct statement :
(i) Two atoms of hydrogen and one atom of oxygen combine together to form one molecule of water.
(ii) Two molecules of hydrogen and one molecule of oxygen combine to form two molecules of water.
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Q. 39. What is difference between 2Cl and Cl2 ?
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Q. 40. Name any two molecules having one atom, two atoms and four atoms.
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Q.41. Explain the existence of various elements and compounds.
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Q. 42. A and B are two different atoms. State whether A and B are metals or non-metals in the following compounds or materials :
(i) A4
(ii) B2
(iii) AB4
(iv) A+2(B-1)2
(v) A2B2
(vi) A+B-
(vii) B
(viii) B+3(A-1)3.
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Q. 43. Differentiate between atom and molecule.
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Q. 44. How many kinds of atoms are present in a molecules of
(i) Sulphuric acid and
(ii) Copper carbonate.
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Q.45. Separate atoms and molecules from the following stable elements :
Argon, Hydrogen, Helium, Oxygen, Potassium, Neon, Chlorine, Nitrogen, Sodium, Copper.
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Q. 46. When one molecule of water is decomposed, how many atoms of hydrogen and oxygen are obtained ?
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Q. 47. The atomic masses of hydrogen, carbon, nitrogen, oxygen and sulphur are 1u, 12u, 14u, 16u, 32u respectively. Prove that the atoms of the following compounds combine in simple mass to atomic mass ratio :
CH4, H2O, CO2, NH3, SO2.
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Q. 48. Differentiate between an atom of hydrogen and a molecule of hydrogen.
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Q. 49. What is the difference between a molecule of oxygen and a molecule of water ?
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Q.50. State and explain an ion.
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Q. 51. State and explain ionic compound.
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Q. 52. Separate the ions in the following compounds :
Sodium fluoride, Potassium bromide, Calcium oxide, Silver sulphide.
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Q. 53. What is formula of a molecule ?
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Q. 54. State and explain the term ‘valency’. What is use of valency ?
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Q. 55.Write the symbols and valency for the common ions of the following :
Potassium, Iodine, Copper, Barium, Fluoride, Cobalt, Sulphide, Aluminium, Zinc, Calcium, Lead, Gold, Sodium, Chloride.
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Q.56. Explain why all elements have a charged valency.
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Q. 57. Write the name and valency of the following polyatomic ions :
Nitrate, Phosphate, Ammonium, Bicarbonate, Hydroxide, Sulphite, Sulphate, Carbonate.
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Q.58. How will you write a molecular formula ?
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Q. 59. Write ‘step-wise’ the formula for the following :
(i) Ammonium sulphate
(ii)Potassium carbonate
(iii) Hydrogen sulphide
(iv) Zinc carbonate
(v) Methane
(vi) Cupric chloride.
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Q. 60. Calcium pyrophosphate is represented by Ca2P2O7. Represent the ferric pyrophosphate.
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Q. 61. Valency of some ions are given below :
Na+1 = 1, Cl-1 = 1,&SO4-2 = 2, Al+3 = 3,CO3-2 = 2
Write the formula of aluminium chloride, aluminium sulphate, aluminium carbonate, sodium chloride, sodium sulphate, sodium carbonate.
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Q. 62. Valency or charge of some ions are given below :
| Ions | Valency/Charge |
| Aluminium ion |
+3 |
| Nitride ion |
-3 |
| Magnesium ion |
+2 |
| Sulphate ion |
-2 |
| Potassium ion |
+1 |
| Fluoride ion | -1 |
Write the chemical formula of the following :
(i) Aluminium nitride
(ii) Aluminium sulphate
(iii) Aluminium fluoride
(iv) Magnesium nitride
(v) Magnesium sulphate
(vi) Magnesium fluoride
(vii) Potassium nitride
(viii) Potassium sulphate
(ix) Potassium fluoride.
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Q. 63. The calcium salt of a hypothetical anion Z has the molecular formula Ca3Z2. Find the valency of Z and write the molecular formula of the aluminium salt of Z.
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Q. 64. The formula of sulphuric acid is H2SO4 and the formula of a metal chloride is MCl3. What is the formula of metal sulphate ?
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Paper By Mr. M. P. Keshari [ For Further Enquiry 09434150289]
