Atoms and Molecules Class 9 MCQs Set 5 | Molecular Mass & Mole Concept | NCERT JKBOSE CBSE

 Introduction

This set comprises 50 MCQs covering molecular mass, formula unit mass, the mole concept, Avogadro's number, and molar mass calculations. The questions test understanding of the relationship between mass, moles, and number of particles. These concepts are fundamental for stoichiometric calculations in chemistry.

⏳ Time Left: 20:00

Progress: 0%

📌 Quiz: SCIENCE

📚 Subject: CHEMISTRY

🏫 Class: CLASS 9

📖 Chapter: Atoms & Molecules-E

📝 Questions: 50

📘 SCIENCE

CHEMISTRY | Atoms & Molecules-E

👤 Your Full Name

🏫 Your Class

📝 Questions: 50 ⏱️ Timer: 20 min

🔊 Enable Correct/Wrong Sound

⏱️ Timer minutes

Q1. A chemical formula represents the:

Colour of a compound

State of a compound

Composition of a compound

Density of a compound

---

Q2. How many hydrogen atoms are present in an H₂S molecule?

One

Two

Three

Four

---

Q3. How many sulphur atoms are present in an H₂S molecule?

One

Two

Three

Zero

---

Q4. The PO₄³⁻ ion contains how many oxygen atoms?

One

Two

Three

Four

---

Q5. The charge on the phosphate (PO₄³⁻) ion is:

+1

-1

-2

-3

---

Q6. Molecular mass is defined as the sum of the:

Atomic numbers

Valencies

Atomic masses

Charges

---

Q7. Molecular mass is expressed in the unit:

g

kg

u

mol

---

Q8. Molecular mass represents the relative mass of a:

Atom

Ion

Molecule

Electron

---

Q9. The molecular mass of water (H₂O) is:

16 u

17 u

18 u

19 u

---

Q10. The atomic mass of hydrogen used in calculations is:

0.5 u

1 u

2 u

16 u

---

Q11. The atomic mass of oxygen used in calculations is:

12 u

14 u

15 u

16 u

---

Q12. The molecular mass of nitric acid (HNO₃) is:

61 u

62 u

63 u

64 u

---

Q13. The atomic mass of nitrogen is taken as:

12 u

13 u

14 u

15 u

---

Q14. Formula unit mass is used for substances made of:

Molecules

Atoms

Ions

Electrons

---

Q15. Formula unit mass is calculated in the same way as:

Atomic number

Molecular mass

Valency

Density

---

Q16. Sodium chloride exists as:

Molecules

Atoms

Ions

Electrons

---

Q17. The formula unit mass of NaCl is:

35.5 u

46 u

58.5 u

60 u

---

Q18. The atomic mass of sodium is:

22 u

23 u

24 u

35.5 u

---

Q19. The atomic mass of chlorine is:

34 u

35 u

35.5 u

36 u

---

Q20. The formula unit mass of CaCl₂ is:

71 u

100 u

111 u

120 u

---

Q21. CaCl₂ contains how many chlorine atoms?

One

Two

Three

Four

---

Q22. The reaction 2H₂ + O₂ → 2H₂O shows the law of:

Definite proportions

Conservation of mass

Multiple proportions

Reciprocal proportions

---

Q23. In the reaction 2H₂ + O₂ → 2H₂O, two molecules of hydrogen combine with:

Two molecules of oxygen

One molecule of oxygen

Three molecules of oxygen

Four molecules of oxygen

---

Q24. 4 u of hydrogen combine with how many units of oxygen?

16 u

24 u

32 u

36 u

---

Q25. The total mass of water formed in the reaction 2H₂ + O₂ → 2H₂O is:

32 u

34 u

36 u

38 u

---

Q26. A chemical equation directly indicates the number of:

Grams

Kilograms

Atoms or molecules

Litres

---

Q27. The SI unit of amount of substance is:

Gram

Kilogram

Mole

Litre

---

Q28. The symbol for mole is:

m

mol

n

g

---

Q29. One mole contains exactly:

6.02 × 10²² entities

6.022 × 10²³ entities

6.22 × 10²³ entities

6.022 × 10²² entities

---

Q30. The number 6.022 × 10²³ is called the:

Atomic number

Molecular number

Avogadro number

Mass number

---

Q31. The Avogadro constant is represented by:

N

n

NA

A

---

Q32. One mole of any substance contains the same number of:

Grams

Atoms or molecules

Electrons

Protons

---

Q33. One dozen represents:

6 items

10 items

12 items

144 items

---

Q34. One gross represents:

12 items

24 items

100 items

144 items

---

Q35. The mass of one mole of a substance is equal to its:

Atomic number

Molecular number

Relative atomic or molecular mass in grams

Valency

---

Q36. Molar mass is expressed in the unit:

u

kg

g

g mol⁻¹

---

Q37. The gram atomic mass of hydrogen is:

0.5 g

1 g

2 g

16 g

---

Q38. 1 g of hydrogen contains:

1 atom

1 molecule

1 mole of atoms

1 mole of molecules

---

Q39. One mole of hydrogen atoms contains:

6.022 × 10²² atoms

6.022 × 10²³ atoms

3.011 × 10²³ atoms

12 × 10²³ atoms

---

Q40. 16 g of oxygen contains:

One oxygen atom

One oxygen molecule

One mole of oxygen atoms

Two moles of oxygen atoms

---

Q41. 16 u of oxygen corresponds to:

One mole of oxygen

One atom of oxygen

One molecule of oxygen

Two atoms of oxygen

---

Q42. The molecular mass of water in grams is:

16 g

17 g

18 g

19 g

---

Q43. Changing the unit from u to g while keeping the number same gives:

Atomic number

Valency

Molar mass

Density

---

Q44. The molar mass of a molecule is also called:

Gram molecular mass

Atomic mass

Formula unit mass

Relative mass

---

Q45. Molecular mass is applicable to substances that exist as:

Ions

Molecules

Electrons

Nuclei

---

Q46. Formula unit mass is applicable to substances that exist as:

Molecules

Atoms

Ions

Neutrons

---

Q47. The quantity of a substance can be expressed in terms of:

Mass only

Volume only

Mass or number of particles

Density only

---

Q48. The symbol used for amount of substance is:

m

n

N

A

---

Q49. The concept of mole makes it easier to count particles by:

Measuring volume

Measuring temperature

Using mass

Using pressure

---

Q50. The molecular mass of carbon dioxide (CO₂) is:

12 u

28 u

44 u

56 u

---

📤 Share

Share this question with your friends

💾 Save

Save this question to your collection

Save to Collection

Download as Image

Save as Text