CBSE Class 9 - Science - CH3 - Atoms and Molecules (MCQs)

Atoms and Molecules 

(MCQs)


Q1: Name the Indian Philospher who "the smallest indivisible particles of matter" as Parmanu

(a) Pakudha Katyayama
(b) Maharishi Kanad
(c) Aryabhatt
(d) Democritus





Q2: Who laid the foundation of laws of Chemical Combination:

(a) Democritus
(b) Lavoisier
(c) Dalton
(d) Proust




Q3: Law of Definite Proportions was proposed by:



(a) Joseph Proust
(b) John Dalton
(c) A Lavosier
(d) Wilhelm Ostwald





Q4: Who introduced the term 'mole' in chemistry?

(a) John Dalton
(b) Amedeo Avagadro
(c) A Lavosier
(d) Wilhelm Ostwald




Q5: The number value 6.022 × 10²³ is also called

(a) Dalton Number
(b) Avagadro's number
(c) Atomic Number
(d) Mass Number




Q6: The number of moles for 52g of He is:
(Atomic Mass of He: 4u)

(a) 6.022 × 10²³
(b) 13
(c) 52
(d) 1







Q7: 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






Q8: Formula for Magnesium Chloride is:

(a) MgCl
(b) Mg₂Cl
(c) MgCl₂
(d) MgCl₄






Q9: Formula for Aluminium Oxide is:

(a) AlO
(b) AlO₂
(c) Al₃O₂
(d) Al₂O₃





Q10: The percentage of Hydrogen in H₂O molecule is

(a) 5.55
(b) 11.11
(c) 44.45
(d) 88.89





Q11: A sample of ammonia molecule irrespective of source, contains 82.35% of Nitrogen and
17.65% of Hydrogen by mass. This data supports:

(a) Law of Conservation of Mass
(b) Law of Definite Proportions
(c) Las of Multiple Proportions
(d) Avagadro's Law





Q12: Which of the following is not correctly matched?

(a) Calcium - Ca
(b) Silver - Ag
(c) Gold - Au
(d) Copper - Co





Q13: Which of the following will have maximum mass?

(a) 0.1 mole of NH₃
(b) 1022 atoms of Carbon
(c) 1022 molecules of CO₂
(d) 1 gm of Fe






Q14: An element X is tetravalent and another element Y is divalent.
The compound formed by these two elements will be:

(a) XY
(b) XY₂
(c) X₂Y
(d) XY₄