Mole Concept questions with answers:
Ques. The ratio of weights of hydrogen and helium is 1 : 2. Find the ratio of number of gram atoms.
(a) 2 : 1
(b) 1 : 1
(c) 1 : 4
(d) 4 : 1
Ques. How many gram atoms of the lightest element weigh same as 1 gram atom of the heaviest element?
Ques. Which one of the following pairs of gases contains the same number of molecules
(a) 16 g of O2 and 14 g of N2
(b) 8 g of O2 and 22 g of CO2
(c) 28 g of N2 and 22 g of CO2
(d) 32 g of O2 and 32 g of N2
Ques. Atoms of which of the following elements exist independently.
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Ques. Among all the naturally occurring elements, which one can generate the maximum number of gram atoms from a given amount?
Ques. Among all the naturally occuring elements, one gram atom of which element contains the maximum amount of it?
Ques. Number of gm of oxygen in 32.2 g Na2SO4 . 10H2O is
Ques. Which property of an element is always a whole number?
(a) Atomic weight
(b) Equivalent weight
(c) Atomic number
(d) Atomic volume
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Ques. 250 ml of a sodium carbonate solution contains 2.65 grams of Na2CO3. If 10 ml of this solution is diluted to one litre, what is the concentration of the resultant solution (mol. wt. of Na2CO3 = 106)
(a) 0.1 M
(b) 0.001 M
(c) 0.01 M
(d) 10–4 M
Ques. Identify the element whose 2 gram atoms weigh 8g.
Ques. Which of the following exist independently?
Ques. A molar solution is one that contains one mole of a solute in
(a) 1000 g of the solvent
(b) One litre of the solvent
(c) One litre of the solution
(d) 22.4 litres of the solution
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Ques. Which one of the following properties of an element is not variable?
(b) Atomic weight
(c) Equivalent weight
(d) All of these
Ques. The number of water molecules in 1 litre of water is
(b) 18 x 1000
(d) 55.55 NA
Ques. Find the number of gram molecules of hydrogen present in 1 gram molecule of methane gas.
Ques. The types of forces that holds the atoms together in a molecule is
(a) Covalent bonds
(b) Ionic bonds
(c) Gravitational force
(d) Magnetic forces
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Ques. The numbers of moles of BaCO3 which contain 1.5 moles of oxygen atoms is
(d) 6.02 x 1023
Ques. The modern atomic weight scale is based on
Ques. The weight of 1 gram atom of sulphur is
(a) 32 amu
(b) 32 grams
(c) 16 amu
(d) 16 grams
Ques. Number of molecules in 100 ml of each of O2, NH3 and CO2 at STP are
(a) In the order CO2 < O2 < NH3
(b) In the order NH3 < O2 < CO2
(c) The same
(d) NH3 = CO2 < O2
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Ques. The number of atoms present in a molecule is called its atomicity. Then, the atomicity of phosphorus and sulphur is _____ and _____ respectively.
(a) 1, 2
(b) 3, 6
(c) 2, 4
(d) 4, 8
Ques. The total number of protons in 10 g of calcium carbonate is (N0 = 6.023 x 1023)
(a) 1.5057 x 1024
(b) 2.0478 x 1024
(c) 3.0115 x 1024
(d) 4.0956 x 1024
Ques. The weight of 1/4 mole of calcium atom =
(a) 40 grams
(b) 20 grams
(c) 10 grams
(d) 5 grams
Ques. The total number of gm-molecules of SO2Cl2 in 13.5 g of sulphuryl chloride is
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Ques. The symbol of carbon is C. It means that
(a) ‘C’ represents one atom of carbon.
(b) ‘C’ also represents 1 mole of carbon atoms.
(c) ‘C’ also represents 12g of C.
Ques. The largest number of molecules is in
(a) 34 g of water
(b) 28 g of CO2
(c) 46 g of CH3OH
(d) 54 g of N2O5
Ques. The weight of 1/4 mole of atom of an element is 5 grams. Identify the substance
Ques. Which of the following exists in mono-atomic form?
Ques. 2g of oxygen contains number of atoms equal to that in
(a) 0.5 g of hydrogen
(b) 4g of sulphur
(c) 7g of nitrogen
(d) 2.3 g of sodium
Ques. The mass of one atom of an unknown element is 4 x 1.66 × 10–24g. The element is
Ques. The weight of 1 molecule of a substance is 98 amu. The substance is
(a) Calcium carbonate
(b) Sulphuric acid
(c) Sodium chloride
(d) Phosphoric acid
Ques. One mole of calcium phosphide on reaction with excess of water gives
(a) One mole of phosphine
(b) Two moles of phosphoric acid
(c) Two moles of phosphine
(d) One mole of phosphorus pentoxide
Ques. The gram atomic weight of oxygen is
(a) 16 amu
(b) 16 g
(c) 32 amu
(d) 32 g
Ques. Molarity of liquid HCl with density equal to 1.17 g / cc is
Ques. Which of the following contains same number of molecules as in 1 mole of any substance?
(a) 32 g of sulphur
(b) 18 g of H2O
(c) 17 g of ammonia
(d) 16 g of methane
Ques. The number of oxygen atoms in 4.4 g of CO2 is approx.
(a) 1.2 x 1023
(b) 6 x 1022
(c) 6.2 x 1022
(d) 12 x 1023
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Ques. The ratio of number of molecules present in 1 gram mole of O2 to one gram mole of SO2 is
(a) 1 : 4
(b) 1 : 2
(c) 1 : 8
(d) 1 : 1
Ques. 12 g of Carbon contains equal number of atoms as
(a) 12 grams of Mg
(b) 40 grams of Calcium
(c) 32 grams of Oxygen
(d) 7 grams of nitrogen
Ques. The number of moles of sodium oxide in 620 g of it is
(a) 1 mole
(b) 10 moles
(c) 18 moles
(d) 100 moles