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BASIC CONCEPTS OF CHEMISTRY
1.
4.6 × 1022 atoms of an element weight 13.8 g. The atomic mass of the element
is :
(a) 290
(b) 180
(c) 34.4
(d) 10.4
2.
The number of molecules in 89.6 litre of a gas at NTP are : [BHU 1992]
(a) 6.02 × 1023
(b) 2 × 6.02 × 1023
(c) 3 × 6.02 × 1023
(d) 4 × 6.02 × 1023
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Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
3.
The total number of protons in 10 g of calcium carbonate is [CPMT 1992]
(a) 3.0115 × 1024
(b) 1.5057 × 1024
(c) 2.0478 × 1024
(d) 4.0956 × 1024
4.
A gaseous mixture contains oxygen and nitrogen in the ratio of 1 : 4 by
mass. Therefore, the ratio of their number of molecules is :
(a) 1 : 4
(b) 1 : 8
(c) 7 : 32
(d) 3 : 16
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Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
5.
If a mole was to contain 1.0 × 1024 particles, the mass of one mole of oxygen is :
(a) 53.2 g
(b) 5.32 g
(c) 32.0 g
(d) 16.0 g
6.
Number of g of oxygen is 32.2g Na2SO4. 10H2O is
(a) 20.8
(b) 22.4
(c) 2.24
(d) 2.08
7.
The number of oxygen atoms in 4.4g of CO2 is approx…
(a) 1.2 × 1023
(b) 16 × 1022
23
(c) 6 × 10
(d) 12 × 1023
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[Haryana PMT 2000
[CBSE PMT 1990]
Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
8.
The volume occupied by 4.4 g of CO2 at STP is…
[Pb. CET 1997, 2002 : AFMC 1997, 2004]
(a) 22.4 L
(b) 2.24 L
(c) 0.224 L
(d) 0.1 L
9.
The number of water molecules present in a drop of water (volume 0.0018 ml) at room
temperature is… (density = 1 gm ml−1)
[DCE 2000]
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(a) 6.023 × 10
(b) 1.084 × 1018
(c) 4.84 × 1017
(d) 6.023 × 1023
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Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
10.
19.7 kg of gold was recovered from a smuggler. How many atoms of gold were
recovered (Au = 197)
[Pb. CET 1985]
(a) 100
(b) 6.02 × 1023
(c) 6.02 × 1024
(d) 6.02 × 1025
11.
Number of molecules in 100 ml of each of O2, NH3 and CO2 at STP are
[Bihar MADT 1985]
(a) In the order CO2 < O2 < NH3
(b) In the order NH3 < O2 < CO2
(c) The same
(d) NH3 = CO2 < O2
12.
The number of electrons in a mole of hydrogen molecule is…
(a) 6.02 × 1023
(b) 12.046 × 1023
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(c) 3.0115 × 10
(d) Indefinite
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[CPMT 1987]
Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
13.
The numbers of moles of BaCO3 which contain 1.5 moles of oxygen atoms is
[EAMCET 1991]
(a) 0.5
(b) 1
(c) 3
(d) 6.02 ×1023
14.
How many molecules are present in one gram of hydrogen… [AIIMS 1982]
(a) 6.02 × 1023
(b) 3.01 × 1023
23
(c) 2.5 × 10
(d) 1.5 × 1023
15.
The total number of gm-molecules of SO2Cl2 in 13.5g of sulphuryl chloride is
[CPMT 1992]
(a) 0.1
(b) 0.2
(c) 0.3
(d) 0.4
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Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
16.
The largest number of molecules is in
[BHU 1997]
(a) 34g of water
(b) 28g of CO2
(c) 46g of CH3OH
(d) 54g of N2O5
17.
The number of g-atom of oxygen in 6.02 × 1024 CO molecule is…
(a) 1
(b) 0.5
(c) 5
(d) 10
18.
80 g of oxygen contains as many atoms as in…
[BHU 1992; KECT 2008]
(a) 10 g of hydrogen
(b) 50 g of hydrogen
(c) 80 g of hydrogen
(d) 1 g of hydrogen
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[DCE 2006]
Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
19.
10 ml O2 and H2 kept at same temperature and pressure. What is true about their
number of molecules
[Orissa JEE 2009]
(a) N 02 > N H 2
(b) N 02 < N H 2
(c) N 02 = N H 2
20.
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(d)
1
N 0 + N H 2 = 1 mole
2 2
Common salt obtained from sea-water contains 95% NaCl by mass. The approximate
number of molecules present in 10.0 g of the salt is…
[DIMET 2009]
21
22
(a) 10
(b) 10
23
(c) 10
(d) 1024
Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433
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Basic Concepts of Chemistry / 1_3_A/Ph : 079-30004433