JEE Main - Molar mass percentage composition empirical and molecular formulae One Line Questions & Answers

1. If the empirical formula mass of a compound is 29 g/mol and its molar mass is 58 g/mol, what is the value of 'n' in the relation Molecular Formula = (Empirical Formula)n? — 2

2. The empirical formula of a carbohydrate is CH2O. If the molar mass of the carbohydrate is 180 g/mol, how many carbon atoms are there in one molecule of the carbohydrate? — 6

3. What is the molar mass of methane (CH4)? (Atomic masses: C = 12, H = 1) — 16 g/mol

4. What is the molar mass of potassium carbonate (K2CO3)? (Atomic masses: K = 39, C = 12, O = 16) — 100 g/mol

5. What is the molar mass of a compound if its empirical formula is CH and its molar mass is twice the molar mass of its empirical formula? — 26 g/mol

6. What is the percentage by mass of nitrogen in ammonia (NH3)? (Atomic masses: N = 14, H = 1) — 82%

7. What is the percentage by mass of oxygen in pure sulfuric acid (H2SO4)? — 51.0%

8. Which of the following is the molar mass of water (H2O)? (Atomic masses: H = 1, O = 16) — 18 g/mol

9. What is the percentage by mass of carbon in glucose (C6H12O6)? (Atomic masses: C = 12, H = 1, O = 16) — 40.0%

10. What is the molar mass of carbon dioxide (CO2)? (Atomic masses: C = 12, O = 16) — 44 g/mol

11. The empirical formula of glucose is CH2O. What is the molar mass of glucose if its molecular formula is C6H12O6? — 180 g/mol

12. What is the molar mass of ethanol (C2H5OH)? (Atomic masses: C = 12, H = 1, O = 16) — 46 g/mol

13. What is the percentage by mass of sulfur in sulfur dioxide (SO2)? (Atomic masses: S = 32, O = 16) — 66.7%

14. What is the percentage by mass of iron in iron(III) oxide (Fe2O3)? (Atomic masses: Fe = 56, O = 16) — 60.0%

15. What is the molar mass of the empirical formula CH2Cl2? — 84.5 g/mol

16. What is the percentage by mass of hydrogen in methane (CH4)? (Atomic masses: C = 12, H = 1) — 6.25%

17. What is the molar mass of calcium carbonate (CaCO3)? (Atomic masses: Ca = 40, C = 12, O = 16) — 100 g/mol

18. If 10 grams of a compound contain 4 grams of element A and 6 grams of element B, and the atomic mass of A is 10 amu and B is 15 amu, what is the empirical formula? — A2B3

19. A compound contains 5.88% hydrogen, 70.59% carbon, and 23.53% oxygen by mass. What is its empirical formula? — C3H4O

20. If the empirical formula of a compound is C2H5 and its molar mass is 58 g/mol, what is its molecular formula? — C4H10

21. If a compound has the molecular formula C2H6, what is its empirical formula? — CH3

22. The empirical formula of a compound is C2H6O. If its molar mass is 46 g/mol, what is its molecular formula? — C2H6O

23. If the empirical formula of a compound is C3H4 and its molar mass is 80 g/mol, what is its molecular formula? — C3H4

24. A compound contains 60% carbon, 8% hydrogen, and 32% oxygen by mass. What is its empirical formula? — C3H4O

25. If the empirical formula of a compound is C3H6O2 and its molar mass is 118 g/mol, what is its molecular formula? — C3H6O2

26. If a compound has an empirical formula of C3H7 and a molar mass of 86 g/mol, what is its molecular formula? — C6H14

27. A compound has the molecular formula C3H8. What is its empirical formula? — C3H8

28. The empirical formula of a compound is C4H8O2. If its molar mass is 88 g/mol, what is its molecular formula? — C4H8O2

29. If the empirical formula of a compound is C5H10O and its molar mass is 100 g/mol, what is its molecular formula? — C5H10O

30. The molar mass of a compound is 78 g/mol. Its empirical formula is CH. What is its molecular formula? — C6H6

31. If the percentage composition of a compound is 10% Hydrogen and 90% Carbon by mass, what is its empirical formula? — CH

32. A compound contains 75% carbon and 25% hydrogen by mass. If its molar mass is 16 g/mol, what is its molecular formula? — CH4

33. A compound contains 85.7% carbon and 14.3% hydrogen by mass. What is its empirical formula? — CH2

34. The empirical formula of a compound is CH2. If its molar mass is 42 g/mol, what is its molecular formula? — C3H6

35. The molar mass of a compound is 128 g/mol. Its empirical formula is CH2. What is its molecular formula? — C8H16

36. A compound has 24.24% carbon, 4.04% hydrogen, and 71.72% chlorine by mass. What is its empirical formula? — CHCl

37. A compound has an empirical formula of CH2Cl. If its molar mass is 99 g/mol, what is its molecular formula? — C3H6Cl3

38. If the empirical formula of a compound is CH2O and its molar mass is 180 g/mol, what is its molecular formula? — C6H12O6

39. A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. If its molar mass is 180 g/mol, what is its molecular formula? — C6H12O6

40. A sample of a compound contains 8.33 g of carbon, 1.39 g of hydrogen, and 11.08 g of oxygen. What is the empirical formula of this compound? — CH2O

41. The percentage composition of a compound is determined by: — Dividing the mass of the element by the total mass of the compound and multiplying by 100.

42. Which of the following compounds has the same empirical formula as its molecular formula? — Water (H2O)

43. A compound is found to contain 47.06% potassium, 14.47% carbon, and 38.47% oxygen by mass. What is its empirical formula? — K2CO3

44. Which of the following represents the simplest whole-number ratio of atoms of each element in a compound? — Empirical formula

45. A compound has an empirical formula of N2O4. What is its simplest whole-number ratio of atoms? — NO2

46. The percentage composition of an oxide of nitrogen is 30.4% nitrogen. What is its empirical formula? — NO2

47. A compound has an empirical formula of P2O5. If its molar mass is 284 g/mol, what is its molecular formula? — P4O10

48. What information does the molecular formula provide that the empirical formula does not? — The exact number of atoms of each element in a molecule.

49. Which of the following statements about empirical and molecular formulas is INCORRECT? — The empirical formula represents the actual number of atoms in a molecule.

50. What is the definition of molar mass percentage composition of a compound? — The ratio of the molar mass of an element to the molar mass of the compound, multiplied by 100.

Molar mass percentage composition empirical and molecular formulae - One Line Questions