Mole Concept Level # 2

MOLE CONCEPT Q.1 Q.2 Q.3 Which one of the following properties of an element is not variable ? (A) Valency (B) Equivalent mass (C) Atomic mass (D) All the three An element A is tetravalent and another element B is divalent. The formula of the compound formed from these elements will be(A) A2B (B) AB (C) AB2 (D) A2B3 The vapour density of gas A is four times that of B. If molecular mass of B is M, then molecular mass of A is (A) M (B) 4M (C) Q.4 Q.5 Q.6 Q.7 M 4 Q.8 isobutane, then the amount of oxygen that would be required for combustion of 1kg of it will be(A) 1.8 kg (B) 2.7 kg (C) 4.5 kg (D) 3.58 kg Q.9 1 gm - atom of nitrogen represents (A) 6.02 x 1023 N2 molecules (B) 22.4 lit. of N2 at N.T.P. (C) 11.2 lit. of N2 at N.T.P. (D) 28 gm of nitrogen. Q.10 The moles of O2 required for reacting with 6.8 gm of ammonia. (..... NH3 +..... O2  ..... NO + ..... H2O) is (A) 5 (B) 2.5 (C) 1 (D) 0.5 Q.11 If isotopic distribution of C–12 and C–14 is 98% (D) 2M Percentage of copper and oxygen in sample of CuO obtained by different methods were found to be same. This proves the law of (A) Constant proportion (B) Multiple proportion (C) Reciprocal proportion (D) None of these 6 gm of carbon combines with 32 gm of sulphur to form CS2. 12 gm of C also combine with 32 gm of oxygen to form carbondioxide. 10 gm of sulphur combines with 10 gm of oxygen to form sulphur dioxide. Which law is illustrated by them (A) Law of multiple proportions (B) Law of constant composition (C) Law of Reciprocal proportions (D) Gay Lussac's law. Two elements X (at mass 16) and Y (at mass 14) combine to form compounds A, B and C. The ratio of different masses of Y which combine with a fixed mass of X in A, B and C is 1 : 3 : 5. If 32 parts by mass of X combines with 84 parts by mass of Y in B, then in C, 16 parts by mass of X will combine with(A) 14 parts by mass of Y (B) 42 parts by mass of Y (C) 70 parts by mass of Y (D) 84 parts by mass of Y If one mole of ethanol (C2H5OH) completely burns to form carbon dioxide and water, the weight of carbon dioxide formed is about (A) 22 gm (B) 45 gm (C) 66 gm (D) 88 gm If LPG cylinder contains mixture of butane and and 2% respectively, then the number of C–14 atoms in 12 gm of carbon is (A) 1.032 × 1022 (B) 3.01 × 1022 23 (C) 5.88 × 10 (D) 6.02 × 1023 Q.12 If 3.01 x 10 20 molecules are removed from 98 mg of H2SO4, then the number of moles of H2SO4 left are(A) 0.1 × 10–3 (B) 0.5 × 10–3 (C) 1.66 × 10–3 (D) 9.95 × 10–2 Q.13 Total number of atoms of all elements present in 1 mole of ammonium dichromate [(NH4)2Cr2O7] is (A) 14 (B) 19 (C) 6 × 1023 (D) 114 × 1023 Q.14 Q.15 X gm of Ag was dissolved in HNO3 and the solution was treated with excess of NaCl. When 2.87 gm of AgCl was precipitated the value of x is (A) 1.08 gm (B) 2.16 gm (C) 2.70 gm (D) 1.62 gm What mass of calcium chloride in grams would be enough to produce 14.35 gm of AgCl. (At. mass Ca = 40, Ag = 108) (A) 5.55 gm (B) 8.295 gm (C) 16.59 gm (D) 11.19 gm MOLE CONCEPT Q.16 Total no. of atoms in 44 gm of CO2 is (A) 6.02 × 1023 (B) 6.02 × 1024 (C) 1.806 × 1024 (D) 18.06 × 1022 Q.17 If the density of water is 1 gm/cm3, then the volume occupied by one molecule of water is approximately(A) 18 cm 3 (B) 22400 cm 3 –23 3 (C) 6.02 × 10 cm (D) 3.0 × 10–23 cm 3 Q.18 Q.19 Q.20 How many grams are contained in 1gm-atom of Na (A) 13 gm (B) 23 gm (C) 1 gm (D) 1/23 gm 1.35 gm of pure Ca metal was quantitatively converted into 1.88 gm of pure CaO. What is atomic weight of Ca (A) 40.75 (B) 50 (C) 60 (D) 70 The % loss in weight after heating a pure sample of potassium chlorate (M. wt. 122.5) will be (A) 12.25 (B) 24.50 (C) 39.17 (D) 49.00 Q.21 The minimum quantity in gram of H2S needed to precipitate 63.5 gm of Cu+2 will be nearly (A) 63.5 gm (B) 31.75 gm (C) 34 gm (D) 20 gm Q.22 Mass of H2O in 1000 kg CuSO4.5H2O is - (Cu = 63.5) (A) 360.5 kg (B) 36.05 kg (C) 3605 kg (D) 3.605 kg Phosphine (PH3) decomposes to produce vapours of phosphorus and H2 gas. What will be the change in volume when 100 mL of phosphine is decomposed ? (A) + 50 mL (B) 500 mL Q.23 (C) + 75 mL Q.24 Q.25 4.4 gm of CO2 and 2.24 litre of H2 at STP are mixed in a container. The total number of molecules present in the container will be (A) 6.022 × 1023 (B) 1.2044 × 1023 (C) 2 moles (D) 6.023 × 1024 Q.27 Find the volume of CO2 obtained at S.T.P. on heating 200 gm of 50% pure CaCO3 (A) 11.2 litre (B) 22.4 litre (C) 44.8 litre (D) None of these Q.28 2.76 gm of silver carbonate on being strongly heated yields a residue weighing (A) 2.16 gm (B) 2.48 gm (C) 2.32 gm (D) 2.64 gm Q.29 A sample of AlF3 contains 3.0 × 1024 F– ions. The number of formula units in this sample are (A) 9.0 × 1024 (B) 3.0 × 1024 (C) 0.75 × 1024 (D) 1.0 × 1024 Q.30 Calculate the gm quantity of Na2CO3 which has same No. of atoms as the No. of protons present in 10 gm CaCO3 (A) 20 gm (B) 88.33 gm (C) 44 gm (D) 60 gm The mass of CaCO3 produced when carbon dioxide is passed in excess through 500 ml of 0.5 M Ca(OH)2 will be- Q.31 Q.32 (D) – 500 mL In the reaction 4A + 2B + 3C  A4B2C3 , what will be the number of moles of product formed, starting from one mole of A, 0.6 mole of B and 0.72 mole of C ? (A) 0.25 (B) 0.3 (C) 0.24 Q.26 Q.33 (D) 2.32 8 gm of O2 has the same number of molecules as(A) 7 gm of CO (B) 14 gm of CO (C) 14 gm of CO2 (D) 12 gm of CO2 1 Q.34 (A) 10 gm (B) 20 gm (C) 50 gm (D) 25 gm. The mass of 70% pure H 2 SO 4 required for neutralisation of 1 mol of NaOH (A) 49 gm (B) 98 gm (C) 70 gm (D) 34.3 gm A sample of hard water is found to contain 40 mg of Ca+2 ion per litre. The amount of washing soda (Na2CO3) required to soften five litres of the sample would be (A) 1.06 gm (B) 5.3 gm (C) 53 mg (D) 530 mg The mass of oxygen that would be required to produce enough CO, which completely reduces 1.6 MOLE CONCEPT kg Fe2O3 (at. mass Fe = 56) is- Q.35 Q.36 (A) 240 gm (B) 480 gm (C) 720 gm (D) 960 gm 1.5 gm of divalent metal displaced 4 gm of copper (at. wt. = 64) from a solution of copper sulphate. The atomic weight of the metal is(A) 12 (B) 24 (C) 48 (D) 6 Avogadro's number of Rupees can be spent in ..........years if 10 lac rupees per second are spent (A) 1.91 × 1010 year (B) 2.91 × 1010 year 3.91 × 1010 year (D) 4.91 × 1010 year (C) Q.37 The amount of sulphur required to produce 100 moles of H2SO4 is (A) 3.2 × 103 gm (B) 32.65 gm (C) 32 gm Q.38 Q.39 Q.40 (D) 3.2 gm The vapour density of a mixture containing NO2 and N2O4 is 38.3 at 27º C. The moles of NO2 in 100 mole mixture is (A) 33.48 (B) 53.52 (C) 28.3 (D) 76.6 Assuming that petrol is iso-octane (C8H18) and has density 0.8 gm/ml, 1.425 litre of petrol on complete combustion will consume oxygen (A) 50 L (B) 125 L (C) 125 mol (D) 50 mol The conversion of oxygen to ozone occurs to the extent of 15% only. The mass of ozone that can be prepared from 67.2 L of oxygen at S.T.P. will be (A) 14.4 gm (B) 96 gm (C) 640 gm (D) 64 gm ANSWER KEY LEVEL # 2 Q .No . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 An s. C C B A C C D D C D A B D B A C D B A C Q .No . 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 An s. C A C C A B B A D B D C D B B B A A C A 1