A compound has an empirical formula, C2H2O. If the experimental molecular weight is found to be in the range of 160-170, the molecular formula of this compound is: (Atomic weight: C = 12.1, H = 1, O = 16).
Correct answer: C. C8H8O4
- A. C3H6O3
- B. C4H4O2
- C. C8H8O4
- D. C6H6O3
Explanation
The molecular mass of the empirical formula is 2(12.1) + 2(1) + 16 = 42.2Now, we need to find 'n' Experimental molecular weight = 165 (average of the given range of 160-170)We can find n byn= (experimental molecular weight) / (empirical formula mass) = 165/42.2 = 3.9 Hence, 'n' is approximately 4 Now, 4C2* 4H2* O4 = C8H8O4 Hence, option C is the correct option.
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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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