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Complete combustion of 8.20 g of a hydrocarbon produced 25.3 g of CO2 and 11.6 g of H2O. What is the empirical formula for the hydrocarbon? Insert subscripts as necessary.

User Hypermiler
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Final answer:

The empirical formula of the hydrocarbon from the given combustion data is approximately CH₂, calculated by determining moles of carbon and hydrogen from the mass of CO₂ and H₂O, and finding their simplest ratio.

Step-by-step explanation:

To determine the empirical formula of a hydrocarbon from its combustion products, we need to find the moles of carbon and hydrogen present in the original compound. Because complete combustion of a hydrocarbon produces CO₂ and H₂O, we can use the masses of these products to find the moles of C and H, and from there calculate the empirical formula.

First, we calculate the moles of carbon in 25.3 g of CO₂ using its molar mass (44.01 g/mol):

25.3 g CO₂ × (1 mol CO₂ / 44.01 g CO₂) = 0.575 moles of C

For hydrogen, we first determine the moles in 11.6 g of H₂O (18.02 g/mol):

11.6 g H₂O × (1 mol H₂O / 18.02 g H₂O) × (2 mol H / 1 mol H₂O) = 1.29 moles of H

Now we divide by the smaller number of moles to get the ratio:

C: 0.575 moles / 0.575 moles = 1

H: 1.29 moles / 0.575 moles = 2.24 ≈ 2

The empirical formula of the hydrocarbon is approximately CH₂.

User Sundowatch
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