Master Class 9 Science – Atoms and Molecules with Our MCQ Mock Test!

Are you confident about the laws of chemical combination, atomic structure, and writing chemical formulas? Test your understanding with this MCQ-based mock test on Atoms and Molecules, designed specially for Class 9 students. This test covers all key concepts — from Dalton’s atomic theory and the law of conservation of mass to mole concept, atomic mass, molecular mass, and numerical problems based on these topics.

With well-curated multiple-choice questions following the latest CBSE syllabus, this mock test gives you a complete exam-like experience. It helps you strengthen your concepts, improve accuracy, and identify weak areas for focused revision. Perfect for both school exams and quick self-assessment!

Attempt now and see how strong your basics are in Atoms and Molecules!

1. The combining capacity of an element is called

 
 
 
 

2. The mass of 18 ml of water (H2O) at 4° C is equal to

 
 
 
 

3. 2 moles of H atoms at STP occupy volume of

 
 
 
 

4. 18 g of water is electrolysed. The weight of oxygen formed will be

 
 
 
 

5. If the density of water is 1 g cm–3, then the volume occupied by one molecule of water is approximately

 
 
 
 

6. Arrange the following in decreasing order of mass

I. 1023 molecules of H2

II. 0.1 mol of H2O

III. 0.01 mole of atoms of Nitrogen

IV. 2.24 L of O2 at STP

 
 
 
 

7. Which of the following statements is not true about an atom?

 
 
 
 

8. The mass of sodium in 5.85 g of NaCl is

 
 
 
 

9. Molecular weight of CuSO4. 5H2O is equal to [Cu = 63.5 u, S = 32 u, O = 16 u, H = 1 u]

 
 
 
 

10. The mass of magnesium oxide formed by burning 1.2 g of Mg in excess of oxygen is

 
 
 
 

11. Which of the following correctly represents 360 g of water?

(i) 2 moles of H2O

(ii) 20 moles of water

(iii) 6.022 × 1023 molecules of water

(iv) 1.2044 × 1025 molecules of water

 
 
 
 

12. If isotopic distribution of C-12 and C-14 are 98% and 2% respectively, then number of C-14 atoms in 12 g of carbon is

 
 
 
 

13. Which of the following illustrates the law of conservation of mass ?

 
 
 
 

14. A sample of AlF3 contains 3.0 × 1024 F– ions. The number of formula units of this sample is

 
 
 
 

15. Identify the correct one from the following statements.

 
 
 
 

16. Arrange the following in increasing order of number of molecules.

I. 0.5 mol of H2
II. 4.0 g of H2
III. 18 g of H2O
IV. 2.2 g of CO2

 
 
 
 

17. Which is not represented by 1 mole of nitrogen gas ?

 
 
 
 

18. The formula of Ammonium phosphate is

 
 
 
 

19. An element has 8% of sulphur. What will be the minimum molecular weight of the compound ?

 
 
 
 

20. The balancing of chemical equation is based on

 
 
 
 

21. How many moles of electrons weigh equal to one kilogram? [Mass of 1 e = 9.1 × 10–31 kg]

 
 
 
 

22. Identify the correct symbol of Gold.

 
 
 
 

23. Which of the following contains maximum number of atoms ?

 
 
 
 

24. NaOH (aq) + HNO3 (aq) → NaNO3 (aq) + H2O (l) In this reaction Nitric acid acts as

 
 
 
 

25. Which of the following is correct statement ?

 
 
 
 

26. The number of atoms present in 0.5 mol of nitrogen atoms is same as in

 
 
 
 

27. Out of 1.0 g oxygen gas, 1.0 g of oxygen atoms and 1.0 g of ozone, the maximum number of atoms are contained in

 
 
 
 

28. 1.5 g of hydrocarbon on combustion in excess of oxygen produces 4.4 g of CO2 and 2.7 g of H2O, the data illustrates

 
 
 
 

29. Which pair of species contains same percentage of carbon?

 
 
 
 

30. How many atoms are present in 52 u of He ?

 
 
 
 

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