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SAI International School
Subject-Chemistry

Ch-Atoms and Molecules
Topic-Atomicity& molecular mass of the compounds

HOME ASSIGNMENT
OBJECTIVE QUESTIONS
Q.1 Assertion: 16g of oxygen gas is one mole.
Reason: The gram atomic mass of oxygen is 16g

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Q.2 Assertion: 12g of carbon atoms contain 6.022 x 10 atoms.
Reason: Avogadro’s No represents the number of particles present in one
mole of a substance.

Q.3 Assertion: Atomicity of oxygen is 2.
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Reason: 1 mole of an element contains 6.022 X10 atoms.
Q.4 Assertion: The atomic mass of an element is equal to one mole of it.
Reason: One mole represents Avogadro’s number of particles.
Q.5 The number of atoms present in 32 grams of sulphur atoms is:
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a) 6.022 X10
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b) 60.22 X10
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c) 6.022X10
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d) 6.022 X10
Q.6 The molecular mass of Calcium carbonate is 100 so, 6.022 X10
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molecules of it will weigh
a) 100 u
b) 100 g
c) 200 u
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d) 6.022 X10 g
Q.7 The atomic mass of calcium (Ca) is 40 g. The number of moles in 60 g of
calcium ar
a) 0.5 mol b) 2.0 mol
c) 1.5 mol d) 0.75 mol
Q.8 What mass of carbon-di-oxide CO2 will contain 3.011 X10 molecules?
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a) 11.0 g b) 22.0 g
c) 4.4 g d) 44.0 g

Subjective:

S.LNo. Questions Mark Skill
Q.1 What is Avogadro’s constant? 1 R/E

Q.2 Find the number of atoms in the 0.5 mole of C atom? 1 A/Av

Q.3 Calculate the following in 5.6 g of Nitrogen: 3 A/D

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