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Class 9 Science — Chapter 3: Atoms and Molecules
90 practice questions · 30 Easy · 30 Medium · 30 Hard
Free NCERT-aligned multiple-choice practice for Class 9 Science, Chapter 3 (Atoms and Molecules). Practise timed Easy, Medium and Hard quizzes with instant explanations — built for CBSE Board exams, JEE Main and NEET UG. Here are a few sample questions; sign in free to practise all 90.
Sample questions
Q1Easy
The atomic theory was proposed by:
A.Niels Bohr
B.John Dalton✓ correct
C.Rutherford
D.Thomson
Why
John Dalton proposed the atomic theory in 1808.
Q2Medium
Molecular mass of CO₂ (C = 12, O = 16) is:
A.28 u
B.44 u✓ correct
C.32 u
D.48 u
Why
12 + 2(16) = 12 + 32 = 44 u.
Q3Hard
Number of atoms in 0.5 mole of carbon is:
A.3.011 × 10²³✓ correct
B.6.022 × 10²³
C.1.2044 × 10²⁴
D.6.022 × 10²²
Why
0.5 × 6.022 × 10²³ = 3.011 × 10²³ atoms.
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