Mole Concept MCQs | Mole Concept Multiple Choice Questions and Answers

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Questions
1 How many gm moles oxygen are there in 88 gms carbon di oxide?
A 1
B 2
C 3
D 4

Answer: 4
2 What is the average molecular weight of a gas containing 20% N2 (molecular wt. = 28) and 80% SO2 (molecular wt. = 64)?
A 28.4
B 56.8
C 24.4
D 48.8

Answer: 56.8
3 Two statements are given as

(1) When a percentage of fractions is given for gas, it is assumed that it refers to a mole fraction

(2) When a percentage of fractions is given for liquid or solid, it is assumed that it refers to the weight fraction

True statements are

A 1
B 2
C Both 1 and 2
D Neither 1 nor 2

Answer: 2
4 What is the formula for a solid compound that contains 42.11% C, 51.46% O, and 6.43% H and having molecular weight about 341.
A C10 O12H29
B C11O13 H
C C12O11H22
D C12O10H37

Answer: C12O11H22
5 Select the correct statement
A 1 mole of SO2 and 64 g of Ethyl Chloride have same number of moles
B 1 mole of SO2 and 64 g of Ethyl Chloride don`t have same molecular weights
C Both a and b
D Neither a nor b

Answer: 1 mole of SO2 and 64 g of Ethyl Chloride have same number of moles
6 What will be the molecular weight of a chemical, consisting 2 moles of H2SO4, 3 moles of SO2 and 1 mole of NaOH?
A 128
B 228
C 328
D 428

Answer: 428
7 If Avogadro number NA, is changed from 6.022 x 1023 mol-1 to 6.022 x 1020 mol-1 this would change
A the definition of mass in units of grams
B the mass of one mole of carbon
C the ratio of chemical species to each other in a balanced equation
D None of the above

Answer: the mass of one mole of carbon
8 20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (Atomic weight of Mg = 24)
A 75
B 96
C 60
D 84

Answer: 84
9 The number of water molecules is maximum in
A 18 molecules of water
B 1.8 g of water
C 18 g of water
D 18 moles of water

Answer: 18 moles of water
10 1.0 g of magnesium is burnt with 0.56 g O2 in a closed vessel. Which reactant is left in excess and how much? (At. wt: Mg=24; O=16)
A Mg, 0.16 g
B O2, 0.16 g
C Mg, 0.44 g
D O2, 0.28 g

Answer: Mg, 0.16 g
11 How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0M HNO3? The concentrated acid is 70% HNO3.
A 45.0 g conc.HNO3
B 90.0 g conc.HNO3
C 70.0 g conc.HNO3
D 54.0 g conc.HNO3

Answer: 45.0 g conc.HNO3
12 25.3 g of Sodium carbonate Na2CO3 is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, Na+ and carbonate ion CO2−3 are respectively (Molar mass of Na2CO3 = 106 g mol-1)
A 0.955 M and 1.910 M
B 1.910 M and 0.955 M
C 1.90 M and 1.910 M
D 0.477 M and 0.477 M

Answer: 1.910 M and 0.955 M
13 What is the [OH-] in the final solution prepared by mixing 20.0 mL of 0.050 M HCl with 30.0 mL of 0.10 M Ba(OH)2?
A 0.10 M
B 0.40 M
C 0.0050 M
D 0.12 M

Answer: 0.10 M
14 10 g of hydroen and 64g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be
A 2 mol
B 3 mol
C 4 mol
D 1 mol

Answer: 4 mol
15 Volume occupied by one molecule of water (density = 1g cm-3) is
A 9.0 x 10-23 cm3
B 6.023 x 10-23 cm3
C 3.0 x10-23 cm3
D None of these

Answer: 3.0 x10-23 cm3
16 Concentrated aqueous sulphuric acid is 98% H2SO4 by mass and has a density of 1.80 g mL-1. Volume of acid required to make one litre of 0.1 M H2S04 solution is :
A 11.10 mL
B 16.65 mL
C 22.20 mL
D 5.55 mL

Answer: 5.55 mL
17 An organic compound contains carbon, hydrogen, and oxygen. Its elemental analysis gave C, 38.7% and H, 9.67%. The empirical formula of the compound would be
A CH3O
B CH2O
C CHO
D CH4O

Answer: CH3O
18 What is the percent water in CuSO4.5H2O?
A 12
B 14
C 16
D 18

Answer: 16
19 A bucket contains 10 kg of water and 10 kg of NaOH. The respective mass fraction of water and the mole fraction of NaOH are
A 0.5 and 0.31
B 1.0 and 0.62
C 0.5 and 0.69
D 1.0 and 0.50

Answer: 0.5 and 0.31
20 If in a compound the moles of consisting atoms are doubled then the mole fraction of a particular atom will be
A Double
B Half
C Remain same
D None of the mentioned

Answer: Double
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