A carbon compound containing carbon and oxygen has an approximate molar mass equal to 290. On analysis, it is found to contain 50% by mass of each element. Therefore molecular formula of the compound is:
Correct answer: A. C12O9
- A. C12O9
- B. C4O3
- C. C3O4
- D. C9O12
Explanation
Let the mass of the compound = 100g mass of oxygen = 50g moles of oxygen= 50/16 mass of carbon = 50 g moles of carbon= 50/12 mole ratio of carbon to oxygen= 50/12:50/16=4:3 ∴empirical formula =C4O3 Empirical mass =96 And let molecular formula is (C4O3)n ∴96n=290 or n=290/96≈3 ∴ molecular formula is C12O9
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Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.
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