JEE Main - Atomic and molecular masses and mole concept Online Test (MCQ Quiz)

1. What is the atomic mass unit (amu) defined as?

A) 1/12th the mass of an atom of carbon-14 B) 1/12th the mass of an atom of carbon-12 C) 1/16th the mass of an atom of oxygen-16 D) The mass of a proton

2. Which element has an atomic mass closest to 1 amu?

A) Helium B) Hydrogen C) Lithium D) Carbon

3. What is the molar mass of water (H₂O), given atomic masses H=1.008 amu, O=15.999 amu?

A) 16.000 g/mol B) 17.007 g/mol C) 18.015 g/mol D) 19.016 g/mol

4. Avogadro's number (N_A) is approximately:

A) 6.022 x 10^20 B) 6.022 x 10^21 C) 6.022 x 10^22 D) 6.022 x 10^23

5. One mole of any substance contains the same number of entities (atoms, molecules, ions, etc.) as there are atoms in:

A) 12 grams of carbon-14 B) 12 grams of carbon-12 C) 16 grams of oxygen-16 D) 1 gram of hydrogen

6. What is the SI unit for the amount of substance?

A) Gram B) Kilogram C) Mole D) Molecule

7. The molar mass of a substance is numerically equal to its:

A) Atomic mass in amu B) Molecular mass in amu C) Equivalent weight D) Vapor density

8. Which of the following represents the molecular mass of methane (CH₄)?

A) 12 amu B) 16 amu C) 18 amu D) 20 amu

9. If 1 mole of NaCl is dissolved in water, how many moles of Na⁺ ions are produced?

A) 0.5 moles B) 1 mole C) 2 moles D) 23 moles

10. What is the mass of 2 moles of carbon dioxide (CO₂)? (Atomic mass C=12, O=16)

A) 22 g B) 44 g C) 88 g D) 176 g

11. How many moles are present in 18 grams of water (H₂O)? (Molar mass of H₂O ≈ 18 g/mol)

A) 0.5 moles B) 1 mole C) 2 moles D) 18 moles

12. What is the mass of 0.5 moles of sulfuric acid (H₂SO₄)? (Atomic masses H=1, S=32, O=16)

A) 49 g B) 98 g C) 0.5 g D) 196 g

13. The number of moles of solute in 1 liter of solution is called:

A) Molality B) Mole fraction C) Normality D) Molarity

14. What is the mole fraction of a solute if the mole fraction of the solvent is 0.7?

A) 0.3 B) 0.7 C) 1.0 D) 1.7

15. If a solution contains 1 mole of solute and 4 moles of solvent, what is the mole fraction of the solute?

A) 0.2 B) 0.25 C) 0.8 D) 1.0

16. What is the total number of moles of atoms in 1 mole of sodium sulfate (Na₂SO₄)?

A) 3 moles B) 4 moles C) 5 moles D) 7 moles

17. How many atoms are present in 1 mole of gold (Au)?

A) 1 atom B) 6.022 x 10^23 atoms C) 197 atoms D) 197 x 6.022 x 10^23 atoms

18. What is the mass of one molecule of water (H₂O)? (Atomic masses H=1, O=16, N_A = 6.022 x 10^23 mol⁻¹)

A) 18 amu B) 18 grams C) 3.0 x 10⁻²³ g D) 18 x 6.022 x 10^23 g

19. Which of the following has the largest mass?

A) 1 mole of Helium B) 1 mole of Oxygen C) 1 mole of Nitrogen D) 1 mole of Hydrogen

20. The number of moles of a substance is calculated as:

A) Mass / Molar mass B) Molar mass / Mass C) Number of particles / Avogadro's number D) Both a and c

21. What is the molar mass of glucose (C₆H₁₂O₆)? (Atomic masses C=12, H=1, O=16)

A) 180 g/mol B) 192 g/mol C) 178 g/mol D) 200 g/mol

22. How many grams of NaCl are there in 0.1 moles of NaCl? (Atomic masses Na=23, Cl=35.5)

A) 5.85 g B) 58.5 g C) 0.585 g D) 585 g

23. What is the number of moles in 1 kg of substance?

A) 1 / Molar mass (in kg/mol) B) 1000 / Molar mass (in g/mol) C) Molar mass (in g/mol) / 1000 D) 1000 x Molar mass (in g/mol)

24. The term 'gram molecular mass' is synonymous with:

A) Atomic mass B) Molecular mass in amu C) Molar mass D) Equivalent mass

25. What is the concentration of ions in a 0.1 M solution of CaCl₂?

A) 0.1 M B) 0.2 M C) 0.3 M D) 0.4 M

26. If the empirical formula of a compound is CH₂O and its molar mass is 180 g/mol, what is its molecular formula?

A) CH₂O B) C₂H₄O₂ C) C₆H₁₂O₆ D) C₃H₆O₃

27. What is the number of moles of oxygen atoms in 2 moles of carbon dioxide (CO₂)?

A) 1 mole B) 2 moles C) 3 moles D) 4 moles

28. Which of the following has the largest number of molecules?

A) 18 g of H₂O B) 16 g of O₂ C) 14 g of N₂ D) 2 g of H₂

29. What is the molar mass of ozone (O₃)? (Atomic mass O=16)

A) 16 g/mol B) 32 g/mol C) 48 g/mol D) 96 g/mol

30. The mass of a substance containing N_A entities is equal to its:

A) Atomic mass B) Molecular mass C) Molar mass D) Equivalent mass

31. How many moles are present in 44 grams of carbon dioxide (CO₂)? (Molar mass of CO₂ ≈ 44 g/mol)

A) 0.5 moles B) 1 mole C) 2 moles D) 44 moles

32. What is the mass of 0.1 moles of sodium hydroxide (NaOH)? (Atomic masses Na=23, O=16, H=1)

A) 4 g B) 40 g C) 0.4 g D) 400 g

33. The number of moles of solute in 1 kg of solvent is called:

A) Molarity B) Mole fraction C) Molality D) Normality

34. What is the mole fraction of water in a solution prepared by dissolving 18 g of glucose (C₆H₁₂O₆) in 180 g of water?

A) 0.5 B) 0.8 C) 0.9 D) 1.0

35. What is the total number of moles of atoms in 1 mole of calcium phosphate (Ca₃(PO₄)₂)?

A) 7 moles B) 8 moles C) 9 moles D) 13 moles

36. How many molecules are present in 36 grams of water (H₂O)? (Molar mass of H₂O ≈ 18 g/mol, N_A = 6.022 x 10^23 mol⁻¹)

A) 6.022 x 10^23 molecules B) 1.2044 x 10^24 molecules C) 0.5 x 6.022 x 10^23 molecules D) 36 x 6.022 x 10^23 molecules

37. Which of the following has the smallest mass?

A) 1 mole of electrons B) 1 mole of protons C) 1 mole of neutrons D) 1 mole of hydrogen atoms

38. The relative atomic mass of an element is the ratio of the average mass of atoms of an element to:

A) The mass of an atom of carbon-14 B) The mass of an atom of carbon-12 C) 1/12th the mass of an atom of carbon-12 D) 1/16th the mass of an atom of oxygen-16

39. What is the molar mass of ammonia (NH₃)? (Atomic masses N=14, H=1)

A) 15 g/mol B) 16 g/mol C) 17 g/mol D) 18 g/mol

40. How many grams of oxygen gas (O₂) are there in 2 moles of O₂? (Atomic mass O=16)

A) 16 g B) 32 g C) 64 g D) 96 g

41. What is the number of moles in 100 grams of calcium carbonate (CaCO₃)? (Atomic masses Ca=40, C=12, O=16)

A) 1 mole B) 2 moles C) 0.5 moles D) 100 moles

42. The term 'gram atomic mass' is synonymous with:

A) Atomic mass in amu B) Molecular mass C) Molar mass of an element D) Equivalent mass

43. What is the number of moles of hydrogen atoms in 1 mole of methane (CH₄)?

A) 1 mole B) 2 moles C) 3 moles D) 4 moles

44. If a solution has a molarity of 0.5 M and a volume of 2 liters, how many moles of solute are present?

A) 0.25 moles B) 0.5 moles C) 1 mole D) 2 moles

45. Which of the following has the largest number of atoms?

A) 1 mole of H₂ B) 1 mole of O₂ C) 1 mole of N₂ D) 1 mole of He

46. What is the mass of 0.2 moles of sulfuric acid (H₂SO₄)? (Atomic masses H=1, S=32, O=16)

A) 9.8 g B) 19.6 g C) 49 g D) 98 g

47. The number of moles of solute per kilogram of solvent is:

A) Molarity B) Molality C) Mole fraction D) Normality

48. What is the mole fraction of solute if 2 moles of solute are dissolved in 8 moles of solvent?

A) 0.2 B) 0.25 C) 0.5 D) 0.8

49. The molar mass of a compound is numerically equal to its relative molecular mass multiplied by:

A) 1 g/mol B) 1 amu C) 1 kg/mol D) Avogadro's number

50. What is the number of moles in 10 grams of hydrogen gas (H₂)? (Atomic mass H=1)

A) 5 moles B) 10 moles C) 20 moles D) 0.5 moles

Atomic and molecular masses and mole concept - Online Test

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