Mole Concept — Homi Bhabha Class 9 Chemistry MCQs with Solutions
Free Homi Bhabha Class 9 Chemistry Mole Concept MCQs with step-by-step solutions (9 questions). Part of Atoms, Molecules & Structure. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Mole Concept · medium · theory
One mole of any substance contains a number of particles equal to:
A. 1.6 × 10⁻¹⁹
B. 9.8
C. 6.022 × 10²³ (Avogadro number) ✓ Correct
D. 3.0 × 10⁸
Solution: One mole contains Avogadro's number, $6.022 \times 10^{23}$ particles.
Q2 — Mole Concept · medium · numerical
The number of moles in 36 g of water (molar mass 18 g/mol) is:
A. 36 mol
B. 18 mol
C. 2 mol ✓ Correct
D. 0.5 mol
Solution: Moles $= \dfrac{\text{mass}}{\text{molar mass}} = \dfrac{36}{18} = 2$ mol.
Q3 — Mole Concept · hard · numerical
The mass of 0.5 mole of carbon dioxide (molar mass 44 g/mol) is:
A. 0.5 g
B. 22 g ✓ Correct
C. 88 g
D. 44 g
Solution: Mass $= \text{moles} \times \text{molar mass} = 0.5 \times 44 = 22$ g.
Q4 — Mole Concept · hard · numerical
The number of atoms present in 2 moles of a monatomic gas is:
A. 6.022 × 10²³
B. 1.2044 × 10²⁴ ✓ Correct
C. 2 × 10²³
D. 3.011 × 10²³
Solution: Atoms $= 2 \times 6.022 \times 10^{23} = 1.2044 \times 10^{24}$.
Q5 — Mole Concept · medium · numerical
The number of moles in 44 g of carbon dioxide (molar mass 44 g/mol) is:
A. 1 mol ✓ Correct
B. 0.5 mol
C. 44 mol
D. 2 mol
Solution: Moles $= \dfrac{44}{44} = 1$ mol.
Q6 — Mole Concept · easy · theory
One mole of any substance contains the same number of particles, known as Avogadro's number. This number is:
A. 6.022 x 10²²
B. 6.022 x 10²³ ✓ Correct
C. 3.011 x 10²³
D. 1.66 x 10⁻²⁴
Solution: One mole of any substance contains Avogadro's number of particles, which is 6.022 x 10²³.
Q7 — Mole Concept · medium · numerical
How many moles are present in 36 g of water? (Molar mass of water = 18 g/mol)
A. 0.5 mol
B. 18 mol
C. 1 mol
D. 2 mol ✓ Correct
Solution: Number of moles = mass / molar mass = 36 / 18 = 2 mol.
Q8 — Mole Concept · hard · numerical
How many molecules are present in 8 g of methane, CH4? (Molar mass of CH4 = 16 g/mol)
A. 3.011 x 10²²
B. 6.022 x 10²³
C. 3.011 x 10²³ ✓ Correct
D. 1.204 x 10²⁴
Solution: Moles = 8 / 16 = 0.5 mol. Molecules = 0.5 x 6.022 x 10²³ = 3.011 x 10²³.
Q9 — Mole Concept · hard · numerical
What is the mass of 0.25 mole of carbon dioxide, CO2? (Molar mass of CO2 = 44 g/mol)
A. 176 g
B. 11 g ✓ Correct
C. 44 g
D. 22 g
Solution: Mass = number of moles x molar mass = 0.25 x 44 = 11 g.