IIT FOUNDATION
(IX_Ass-5)

1) (a) Calculate the mass of 1.6 gram of atoms of oxygen. [ a) 25.6g ]
(b) Calculate the mass of 5.6 gram atoms of sulphur. [ b) 179.2g ]
(c) Calculate the mass of 2.5 gram atoms of iodine. [ c) 304.8g ]
2) (a) Calculate the mass of 2.5 gram molecules of H2S.
(b) Calculate the mass of 3.6 molecules of glucose (C6H12O6 ) [a) 85g b) 648g]
3) (a) Calculate the number of gram atoms in 669.6 g of iron (at.mass = 55.8)
(b) Calculate the number of gram molecules in 73.6 g of C2H5OH. [ a) 12 b) 1.6]
4) Which of the following has maximum mass?
(a) 2.6 g atoms of sulphur b) 2.6 g molecules of sucrose c) 260 g of iodine
5) Calculate the mass of (a) atom of C14 (b) 1 molecule of N2 (c) 1 molecule of water
(d) 100 molecules of sucrose.
[ a) 2.32 x 10-23g b) 4.65 x 10-23g c) 2.99 x 10-23g d) 5.6 x 10-21g ]
6) Calculate the number of molecules and the number of atoms present in 11.2 litres of oxygen at N.T.P. [ 6.02 x 1023atoms ]
7) Calculate the number of moles in the following:
(a) 7.85 g of iron (b) 4.68 mg of silicon [ a) 0.141 mol b) 1.66 x 10-4mole ]
8) The mass of 94.5 ml of a gas at STP is found to be 0.2231 g. Calculate its mass.[ 52.9 ]
9) (a) Calculate the actual volume of one molecule of water. ( density of water = 1g ml-1 )
(b) Calculate the radius of water molecule assuming to be spherical. [ 2.99 x 10-23 ml ]
10) Calculate the number of molecules in a drop of water weighing 0.05 g (H = 1 ; O = 16)
[1.672 x 1021 ]
11) Calculate the number of atoms in each of the following:
(a) 52 mol of air (b) 52 u of He (c) 52 g of He [a) 3.13 x 1025 b)13 atoms c)7.83 x 1024]
12) Calculate the number of moles in the following masses:
(a) 1.46 metric ton of Aluminium. (b) 7.9 mg of Ca [ a) 5.41 x 104 b) 1.97 x 10-4 mol ]
13) Suppose the chemists had chosen 1020 as the number of particles in a mole. What would be the molecular mass of oxygen gas? [ 5.32 x 10-3 g ]
14) Calculate the number of atoms of each type in 5.3g of Na2 CO3. [ 9.03x1022 atoms ]
15) Calculate the number of molecules present in (a) 1 kg oxygen (b) 1 dm3 of hydrogen at S.T.P. [ a) 1.88 x 1025 b) 2.69 x 1022 ]
16) Calculate the volume occupied by 5.6gm of nitrogen gas at S.T.P. (4.48dm3)
17) Calculate the volume occupied by 0.23gm nitrogen dioxide at S.T.P. (0.112dm3)
18) Calculate the volume occupied by 2.9gm of butane at S.T.P. (1.12dm3)
19) Calculate the weight of 3.36 lit of chlorine gas at S.T.P. (10.65)
20) Calculate the weight of 5.6dm3 of CO2 at S.T.P. (11gm)
21) What is the weight of 7.84 lit of butane at S.T.P (20.3 gm)
22) Calculate (i) number moles (ii) number of molecules in 0.80gm of CUSO4 (i.)0.005 moles ii)3x1021molecules
23) Calculate the number of molecules (i) number of molecules in 6.62gm of lead nitrate. (1.2x1022molecules )
24) Solid of molecule mass 100amu weighs 2g calculate (i) number of moles (ii) number of molecules in the solid.
25) Calculate (i) the weight in grams, (ii) number of moles (iii) number of
molecules in 280cm3 of hydrogen gas at S.T.P.
[ (I) 0.025gm (ii)0.0125 molecules (iii) 7.51x1021 ]
26) Calculate (I) weight in grams (ii) number of moles (iii) number of molecules in 280cm3 of hydrogen gas at stp. [ (I).0.025g ii)0.0125moles iii) 7.5x1021]
27) Calculate (I) weight in grams (ii) number of moles (iii) number of molecules in
1120cm3 of nitrogen gas at S.T.P. [(I) 1.4gm (ii) 0.05 molecules (iii) 0.3x1023 ]
28) Calculate (I) weight in grams (ii) number of moles (iii) number of molecules in
44.8 lit for Carbon dioxide gas at S.T.P. [ (i) 88gm (ii) 2 molecules (iii)1.2x104 ]