Objective questions-atomic and mol physics

Question 1

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Question:   In water, hydrogen and oxygen are present in the ratio of ________.

1.	1:8
2.	2:12
3.	2:3
4.	1:2

Answer:    1

Question 2

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Question:   An example of a triatomic molecule is ___________.

1.	Ozone
2.	Nitrogen
3.	Carbon monoxide
4.	Hydrogen

Answer:    1

Question 3

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Question:   The quantity of matter present in an object is called its _________.

1.	Mass
2.	Volume
3.	Density
4.	Vapour pressure

Answer:    1

Question 4

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Question:   Indivisibility of an atom was proposed by ___________.

1.	Dalton
2.	Rutherford
3.	Thomson
4.	Bohr

Answer:    1

Question 5

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Question:   The value of Avogadro constant is ___________.

1.	6.022 x 1024
2.	6.022 x 1022
3.	60.22 x 1023
4.	6.022 x 1023

Answer:    4

Question 6

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Question:   All samples of carbon dioxide contain carbon and oxygen in the mass ratio of 3:8. This is in agreement with the Law of ___________.

1.	Conservation of Mass
2.	Constant Proportion
3.	Multiple Proportion
4.	Reciprocal Proportion

Answer:    2

Question 7

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Question:   The atomic mass of sodium is 23. The number of moles in 46g of sodium is ________.

1.	2
2.	1
3.	4
4.	0

Answer:    1

Question 8

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Question:   The molecular formula of potassium nitrate is ________.

1.	KNO
2.	KNO3
3.	KNO2
4.	KON

Answer:    2

Question 9

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Question:   Kalium is the Latin name of ________.

1.	Potassium
2.	Krypton
3.	Calcium
4.	Phosphorus

Answer:    1

Question 10

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Question:   The smallest particle of a substance that is capable of independent existence is _________.

1.	Atom
2.	Molecule
3.	Electron
4.	Proton

Answer:    2

Question 11

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Question:   

1.	Atomic number
2.	Atomic mass
3.	Atomic mass scale
4.	Number of electrons

Answer:    2

Question 12

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Question:   

1.	1.25
2.	15
3.	14
4.	12

Answer:    2

Question 13

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Question:   The molecular mass of ammonia is _________.

1.	17 grams
2.	31 grams
3.	20 grams
4.	25 grams

Answer:    1

Question 14

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Question:   Atomic mass of calcium is 40. The mass of 2.5 gram atoms of calcium is _______.

1.	40 g
2.	2.5 g
3.	100 g
4.	80 g

Answer:    3

Question 15

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Question:   The number of atoms in a molecule of the elementary substance is called ________.

1.	Atomic number
2.	Avogadro number
3.	Atomic mass
4.	Atomicity

Answer:    4

Question 16

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Question:   Avogadro number represents the number of atoms in ________.

1.	12 grams of 12C
2.	320 grams of sulphur
3.	32 grams of oxygen
4.	1 gram of 12C

Answer:    1

Question 17

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Question:   The number of moles in 5 grams of calcium is _________.

1.	0.125 mole
2.	5 mole
3.	1.25 mole
4.	12.5 moles

Answer:    1

Question 18

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Question:   2 molecules of nitrogen are represented by ________.

1.	N
2.	2N2
3.	N2
4.	2N

Answer:    2

Question 19

Question:   One mole of H₂O corresponds to

1.	22.4 litre at 1 atm and 250C
2.	6.02 x 1023 atoms of hydrogen and 6.02 x 1023 atoms of oxygen
3.	18 g
4.	1 g

Answer:    3

Question 20

Question:   The number of molecules in 4.25 g of ammonia is approximately

1.	1.0 x 1023
2.	1.5 x 1023
3.	2.0 x 1023
4.	3.5 x 1023