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Determine the simplest formula for a hydrocarbon if the complete combustion of a sample produces 5.28 g of CO₂ and 1.62 g of H₂O?

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Final answer:

The simplest empirical formula for the hydrocarbon is C₂H₃, which is determined by finding the mole ratio of carbon and hydrogen from the combustion products and adjusting to the simplest whole number ratio.

Step-by-step explanation:

To determine the simplest formula for a hydrocarbon given the products of its complete combustion, we will first find the number of moles of carbon and hydrogen in the CO₂ and H₂O produced, respectively. Each mole of CO₂ contains 1 mole of carbon, and each mole of H₂O contains 2 moles of hydrogen.

We calculate the moles of carbon in 5.28 g of CO₂ as follows:
5.28 g CO₂ × (1 mol CO₂ / 44.01 g CO₂) = 0.12 mol of carbon.

We calculate the moles of hydrogen in 1.62 g of H₂O as follows:
1.62 g H₂O × (1 mol H₂O / 18.02 g H₂O) × (2 mol H / 1 mol H₂O) = 0.18 mol of hydrogen.

To determine the simplest whole number ratio, we divide each by the smallest number of moles, which is 0.12 mol:

  • C: 0.12 mol / 0.12 mol = 1
  • H: 0.18 mol / 0.12 mol = 1.5

However, we cannot have a half-atom in a chemical formula, so we multiply each subscript by 2 to get whole numbers:

  • C: 1 × 2 = 2
  • H: 1.5 × 2 = 3

The simplest empirical formula for the hydrocarbon is therefore C₂H₃.

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