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molecular formula and empirical formula of the hydrocarbon

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Complete combustion of a 0.0100 mol sample of a hydrocarbon, CxHy, gives 1.792 L of CO2 at STP and 1.261 g of H2O (a) What is the molecular formula of the hydrocarbon? (b) What is the empirical formula of the hydrocarbon?

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Complete combustion of a 0.0100 mol sample of a hydrocarbon, CxHy, gives 1.792 L of CO2 at STP and 1.261 g of H2O (a) What is the molecular formula of the hydrocarbon? (b) What is the empirical formula of the hydrocarbon?

First find the moles of CO2 by the ideal gas law:
STP = 100 kPa and 273.15 K
V = 1.792 L
By ideal gas law,
PV = nRT
(100 kPa)(1.792 L) = n (8.31 L·kPa·K-1·mol-1)(273.15 K)
So
n = 0.0789 ...

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It determines the molecular formula and empirical formula of certain hydrocarbon. The solution is detailed and received a '5/5' rating from the student who originally posted the question.

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