Atoms And Molecules (Solved)
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Q. 65. State the chemical name, chemical formula for the following compounds :
Baking soda, Washing soda, Blue vitriol, Green vitriol, Lime water, Marble chips, Soda ash, White vitriol or Oil of vitriol, Gypsum.
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Q. 66. Define molecular formula. What is significance of a formula ?
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Q. 67. The chemical formula of calcium oxide is CaO and not Ca2O2. Why ?
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Q.68. Write down the formula of :
(i) Aluminium nitride
(ii) Aluminium phosphate
(iii) Calcium carbonate
(iv) Barium sulphate.
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Q. 69. Write down the formula of :
(i) Sodium carbonate
(ii) Aluminium oxide
(iii) Aluminium chloride
(iv) Hydrogen sulphide
(v) Calcium hydroxide
(vi) Ammonium sulphate
(vii) Calcium bicarbonate
(viii) Ammonium phosphate
(ix) Silver nitrate.
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Q. 70. Write down the name of the compounds given by the following formulae
(i) CaCO3
(ii) (NH4)2CO3
(iii) H2CO3
(iv) SO2 (v) Al2(SO4)3
(vi) MgCl2
(vii) K2SO4
(viii) KNO3
(ix) CaCl2
(x) PbNO3.
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Q. 71. Write down the formula of :
(i) Sodium oxide
(ii) Aluminium chloride
(iii) Sodium sulphide
(iv) Magnesium hydroxide.
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Q. 72. Write down the names of the compounds represented by the following formulae :
(i) Al2(SO4)3
(ii) CaCl2
(iii) K2SO4
(iv) KNO3
(v) CaCO3.
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Q. 73. What is meant by the term chemical formula ?
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Q. 74. How many atoms are present in a
(i) H2S molecule and
(ii) PO43- ion ?
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Q. 75. What is ‘Molecular Mass’ ?
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Q.76. What is formula unit mass ?
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Q. 77. Atomic masses of some elements are given as under :
Hydrogen (H) = 1u; Carbon (C) = 12u; Oxygen (O) = 16u; Nitrogen (N) = 14u;
Sodium (Na)= 23u; Magnesium (Mg) = 24u; Fluorine (F) = 19u;
Chlorine (Cl) = 35.5u; Calcium (Ca) = 40u.
Find the molecular mass of the following :
CH4, C2H2, CH3OH, CO2, H2O, Na2O, MgCl2, NaF, CaCO3, Mg(NO3)2,
NaNO3, Na2CO3, H2, O2, Cl2.
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Q.78. Explain the term ‘mloe concept’.
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Q.79. What is the use of mole concept ?
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Q.80. State Avogadro number.
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Q. 81. What is gram atom ? How is it related to the mole and Avogadro number ?
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Q. 82. State the term ‘gram molecular mass’. How is it related to the mole and Avogadro number ?
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Q. 83.How will you explain that gram atomic mass or gram molecular mass of any substance contains the same number of particles ?
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Q. 84. Atomic mass of C-12 is 12u. On the basis of mole concept, express 1u into grams.
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Q. 85. Is the weight of 1 mole of sodium and 1 mole of oxygen the same ?
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Q. 86. What is number of grams in 0.2 moles of water ?
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Q. 87. Calculate the mass of the following in grams :
(i) 0.5 mole of sulphuric acid
(ii) 0.5 mole of aluminium sulphate
(iii) 0.5 mole of ammonia
(iv) 2 moles of hydrogen chloride.
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Q. 88. Calculate the ratio of moles of 3.6 g of water and 4.4 g of carbon dioxide.[Atomic mass of C = 12u, H = 1u, O = 16u].
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Q. 89. How many mole atoms of oxygen are present in one mole each of potassium chlorate, sodium sulphate, nitric acid and aluminium sulphate ?
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