- 1(current)
Q. No.An organic compound has the following composition by mass: C = 40.687%, H = 5.085%, O = 54.228%. Given vapour density = 59, find its molecular formula.
1. C4H6O4
2. C4H6O2
3. C4H4O2
4. None of the above
The empirical formula and molecular mass of a compound are and 180 g, respectively. The molecular formula of the compound is:
1. C9H18O9
2. CH2O
3. C6H12O6
4. C2H4O2
The molar mass of naturally occurring Argon isotopes is:
| Isotope | Isotopic molar mass | Abundance |
| 36-Ar | 35.96755 g mol–1 | 0.337% |
| 38-Ar | 37.96272 g mol–1 | 0.063% |
| 40-Ar | 39.9624 g mol–1 | 99.600% |
| 1. | 49.99947 g mol-1 | 2. | 39.99947 g mol-1 |
| 3. | 35.59947 g mol-1 | 4. | 45.59947 g mol-1 |
Which of the following could be the molecular formula of a compound if 44 g of it produces 88 g of CO₂ and 36 g of H₂O on complete combustion?
1.
2.
3.
4.
An organic compound contains carbon, hydrogen, and oxygen. If elemental analysis reveals 38.71% carbon and 9.67% hydrogen, which of the following is its empirical formula?
| 1. | CH3O | 2. | CH2O |
| 3. | CHO | 4. | CH4O |
| Assertion (A): | The empirical mass of ethene is half of its molecular mass. |
| Reason (R): | The empirical formula represents the simplest whole-number ratio of the various atoms present in a compound. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
1. Fe3O2
2. Fe2O3
3. Fe2O2
4. Fe3O4
A 2.74 g sample of vanadium oxide contains 1.53 g of vanadium. Given V = 52, determine the empirical formula of the oxide.
1.
2.
3.
4.
A hydrated sodium sulphate salt, Na₂SO₄·nH₂O, loses 55% of its mass on heating to form anhydrous Na₂SO₄. What is the value of n?
| 1. | Five (5) | 2. | Three (3) |
| 3. | Seven (7) | 4. | Ten (10) |
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