Mole Concept Level # 1

MOLE CONCEPT Q.1 Mass of 1 atom of Hydrogen is (A) 1.66 × 10–24 g (B) 10–22 g –23 (C) 10 g (D) 10–25 g Q.2 Which of the following contains the largest number of atoms (A) 11g of CO2 (B) 4g of H2 (C) 5g of NH3 (D) 8g of SO2 Q.3 Four containers of 2L capacity contains dinitrogen as described below. Which one contains maximum number of molecules under similar conditions. (A) 2.5 gm-molecules of N2 (B) 4 gm-atom of nitrogen (C) 3.01 × 1024 N atoms (D) 84 gm of dinitrogen Q.4 What is correct for 10 g of CaCO3 (A) It contains 1g-atom of carbon (B) It contains 0.3 g-atoms of oxygen (C) It contains 12 g of calcium (D) None of these Q.5 The total number of electrons present in 18 mL water (density 1 g/mL) is (A) 6.023 × 1023 (B) 6.023 × 1024 25 (C) 6.023 × 10 (D) 6.023 × 1021 Q.6 4.0 g of caustic soda (mol mass 40) contains same number of sodium ions as are present in(A) 10.6 g of Na2CO3 (mol. mass 106) (B) 58.5 g of NaCl (Formula mass 58.5) (C) 100 ml of 0.5 M Na2SO4 (Formula mass 142) (D) 1mol of NaNO3 (mol. mass 85) Q.7 Q.8 Q.9 No. of oxalic acid molecules in 100 ml of 0.02 N oxalic acid is (A) 6.023 × 1020 (B) 6.023 × 1021 (C) 6.023 × 1022 (D) 6.023 × 1023 One atom of an element ‘X’ weighs 6.664 × 10–23 gm. The number of gram atoms in 40 kg of it is (A) 10 (B) 100 (C) 10000 (D) 1000 The number of oxygen atoms present in 14.6 g of magnesium bicarbonate [Mg(HCO3)2] is (A) 6NA (B) 0.6NA (C) NA (D) 0.5 NA Q.10 One mole of P4 molecules contains - (A) (B) (C) (D) 1 molecule 4 molecules 1/4 × 6.022 × 1023 atoms 24.088 × 1023 atoms Q.11 The total number of protons , electrons and neutrons in 12gm of 6C12 is (A) 1.084 × 1025 (B) 6.022 × 1023 22 (C) 6.022 × 10 (D) 18 Q.12 The number of sodium atoms in 2 moles of sodium ferrocyanide Na4[Fe(CN)6], is(A) 2 (B) 6.023 × 1023 (C) 8 × 6.02 × 1023 (D) 4 × 6.02 × 1023 Q.13 Out of 1.0 g dioxygen, 1.0 g (atomic) oxygen and 1.0 g of ozone, the maximum number of oxygen atoms are contained in (A) 1.0 g of atomic oxygen. (B) 1.0 g of ozone. (C) 1.0 g of oxygen gas. (D) All contain same number of atoms. Q.14 Number of Ca+2 and anhydrous CaCl 2 are (A) NA, 2NA (C) NA, NA Q.15 2 moles of H2 at NTP (A) 11.2 litre (C) 2 litre Cl – ion in 111 g of (B) 2NA, NA (D) None occupy a volume of (B) 44.8 litre (D) 22.4 litre Q.16 4.48 litres of methane at N.T.P. correspond to(A) 1.2 x 1022 molecules of methane (B) 0.5 mole of methane (C) 3.2 gm of methane (D) 0.1 mole of methane Q.17 The weight of a substance that displaces 22.4 litre air at NTP is (A) Mol. wt. (B) At. wt. (C) Eq. wt. (D) all Q.18 Mol. wt. = vapour density × 2, is valid for (A) metals (B) non metals (C) solids (D) gases Q.19 5.6 litre of a gas at N.T.P. weighs equal to 8 gm the vapour density of gas is (A) 32 (B) 16 (C) 8 (D) 40. Q.20 The maximum volume at N.T.P. is occupied by- MOLE CONCEPT (A) (B) (C) (D) 12.8 gm of SO2 6.02 x 1022 molecules of CH4 0.5 mol of NO2 1 gm-molecule of CO2 Q.21 Equal masses of O2 , H2 and CH4 are taken in a container. The respective mole ratio of these gases in container is (A) 1 : 16 : 2 (B) 16 : 1 : 2 (C) 1 : 2 : 16 (D) 16 : 2 : 1 Q.22 Number of moles of water in 488 gm of BaCl 2.2H2O are - (Ba = 137) (A) 2 moles (B) 4 moles (C) 3 moles (D) 5 moles Q.23 16 gm of SOx occupies 5.6 litre at STP. Assuming ideal gas nature, the value of x is (A) 1 (B) 2 (C) 3 (D) None of these Q.24 The density of air is 0.001293 gm/ml at S.T.P. It’s vapour density is (A) 143 (B) 14.3 (C) 1.43 (D) 0.143 Q.25 The percentage of nitrogen in urea is about(A) 38.4 (B) 46.6 (C) 59.1 (D) 61.3 Q.26 The mass of carbon present in 0.5 mole of K4[Fe(CN)6] is (A) 1.8 gm (B) 18 gm (C) 3.6 gm (D) 36 gm Q.27 1.2 gm of Mg (At. mass 24) will produce MgO equal to (A) 0.05 mol (B) 40 gm (C) 40 mg (D) 4 gm Q.28 Insulin contains 3.4% sulphur by mass. What will be the minimum molecular weight of insulin (A) 94.117 (B) 1884 (C) 941 (D) 976 Q.29 The percent of N in 66% pure (NH4)2 SO4 sample is (A) 32 (B) 28 (C) 14 (D) None of these Q.30 The chloride of a metal contains 71% chlorine by weight and the vapour density of it is 50. The atomic weight of the metal will be (A) 29 (B) 58 (C) 35.5 (D) 71 Q.31 The haemoglobin of most mammals contains approximately 0.33% of iron by mass. The molecular mass of haemoglobin is 67200. The number of iron atoms in each molecule of haemoglobin is(A) 3 (B) 4 (C) 2 (D) 6 Q.32 A compound was found to contain 5.37% nitrogen by mass. What is the minimum molecular weight of compound(A) 26.07 (B) 2.607 (C) 260.7 (D) None Q.33 An element (A) (at wt = 75) and another element (B) (at. wt. = 25) combine to form a compound. The compound contains 75% (A) by weight. The formula of the compound will be (A) A2B (B) A3B (C) AB3 (D) AB Q.34 The empirical formula of a compound is CH. Its molecular weight is 78. The molecular formula of the compound will be (A) C2H2 (B) C3H3 (C) C4H4 (D) C6H6 Q.35 An oxide of a metal (M) contains 40% by mass of oxygen. Metal (M) has atomic mass of 24. The empirical formula of the oxide is(A) M2O (B) MO (C) M2O3 (D) M3O4 Q.36 Two oxides of Metal contain 27.6% and 30% oxygen respectively. If the formula of first oxide is M3O4 then formula of second oxide is (A) MO (B) M2O (C) M2O3 (D) MO2 Q.37 The formula which represents the simple ratio of atoms in a compound is called (A) molecular formula (B) structural formula (C) empirical formula (D) rational formula Q.38 On analysis, a certain compound was found to contain 254 gm of iodine (at. mass 127) and 80 gm oxygen (at. mass 16). What is the formula of the compound (A) IO (B) I2O (C) I5O3 (D) I2O5 MOLE CONCEPT Q.39 14g of element X combine with 16g of oxygen. On the basis of this information, which of the following is a correct statement : (A) The element X could have an atomic weight of 7 and its oxide formula XO (B) The element X could have an atomic weight of 14 and its oxide the formula X2O (C) The element X could have an atomic weight of 7 and its oxide is X2O (D) The element X could have an atomic weight of 14 and its oxide is XO2 Q.40 A mixture containing 100 gm H2 and 100 gm O2 is ignited so that water is formed according to the reaction, 2H2 + O2  2H2O; How much water will be formed (A) 113 gm (B) 50 gm (C) 25 gm (D) 200 gm Q.41 0.5 mole of H2SO4 is mixed with 0.2 mole of Ca (OH)2. The maximum number of moles of CaSO4 formed is (A) 0.2 (B) 0.5 (C) 0.4 (D) 1.5 Q.42 How many mol Fe2+ ions are formed, when excess of iron is treated with 50mL of 4.0M HCl under inert atmosphere ? Assume no change in volume (A) 0.4 (B) 0.1 (C) 0.2 (D) 0.8 Q.43 12 litre of H2 and 11.2 litre of Cl2 are mixed and exploded. The composition by volume of mixture is (A) 24 litre of HCl (B) 0.8 litre Cl2 and 20.8 lit HCl. (C) 0.8 litre H2 & 22.4 litre HCl (D) 22.4 litre HCl Q.44 For the reaction : A + 2B  C 5 mole of A and 8 mole of B will produce (A) 5 mole of C (B) 4 mole of C (C) 8 mole of C (D) 13 mole of C Q.45 Hydrogen and oxygen combine to form H2O2 and H 2 O containing 5.93% and 11.2% Hydrogen respectively. The data illustrates(A) Law of conservation of mass (B) Law of constant proportions (C) Law of reciprocal proportions (D) Law of multiple proportions Q.46 If water samples are taken from sea, rivers, clouds, lake or snow, they will be found to contain H2 and O2 in the fixed ratio of 1 : 8. This indicates the law of (A) Multiple proportion (B) Definite proportion (C) Reciprocal proportion (D) None of these. Q.47 One of the following combinations illustrate law of reciprocal proportions(A) N2O3, N2O4, N2O5 (B) NaCl, NaBr, NaI (C) CS2, CO2, SO2 (D) PH3, P2O3, P2O5 Q.48 The law of multiple proportions is illustrated by (A) Carbon monoxide and carbon dioxide (B) Potassium bromide and potassium chloride (C) Water and heavy water (D) Calcium hydroxide and barium hydroxide. Q.49 The law of conservation of mass holds good for all of the following except (A) All chemical reactions (B) Nuclear reactions (C) Endothermic reactions. (D) Exothermic reactions. Q.50 If law of conservation of mass was to hold true, then 20.8 gm of BaCl2 on reaction with 9.8 gm of H2SO4 will produce 7.3 gm of HCl and BaSO4 equal to (A) 11.65 gm (B) 23.3 gm (C) 25.5 gm (D) 30.6 gm MOLE CONCEPT ANSWER KEY LEVEL # 1 Q.No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Ans. A B D B B C A D B D A C D A B C A D B D Q.No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Ans. A B B B B D A C C A B C D D B C C D C A Q.No. 41 42 43 44 45 46 47 48 49 50 Ans. A B C B D B C A B B