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SAI International School
Class-IX
Subject-Chemistry
Topic-Atoms and molecules
Sub topic-Atomic and Relative atomic masses
HOME ASSIGNMENT

OBJECTIVE QUESTIONS
Q.1 Assertion: Mass of Magnesium atom is 24g.
th
Reason: Masses of atoms are compared with 1/12 of the mass of one
atom of C-12
Q.2 2 Assertion: Atomic mass of oxygen is 16 u.
th
Reason: One atom of oxygen is 16 times heavier than 1/12 of the mass
of 1 atom of C-12.
Q.3 Assertion: Atomic mass of Sulphur is 32
th
Reason: 1 amu is equal to 1/12 of the mass of one atom of C-12
Q.4 Assertion : Atomic mass of aluminium is 27.
Reason : An atom of aluminium is 27 times heavier than 1/12th of the
mass of carbon-12 atom.
Q.5 What is the atomic mass of Sulphur?

a) 32g
b) 16g
c) 32 u
d) 16 u
Q.6 The relative atomic mass of Na is

a) 1.008 amu
b) 22.9898 amu
c) 26.9815 amu
d) 15.9994 amu

Q.7 The mass of an atom relative to C-12 is

a) atomic mass
b) atomic number

c) nucleon number
d) relative atomic mass
Q.8 1 u or 1 amu means
a) 1/12th mass of C-12 atoms
b) Mass of C-12 atom
c) Mass of O-16 atom
d) Mass of Hydrogen molecule

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