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Free download in PDF Mole Concept Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams IIT-JEE, AIIMS, NEET etc. These short solved questions or quizzes are provided by Gkseries.
(1)
How many gm moles oxygen are there in 88 gms carbon di oxide?
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(18)
What is the percent water in CuSO4.5H2O?
[A]
12
[B]
14
[C]
16
[D]
18
(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
(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
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