Question

g Use the References to access important values if needed for this question. A researcher took 2.592 g of a certain compound containing only carbon and hydrogen and burned it completely in pure oxygen. All the carbon was changed to 7.851 g of CO2, and all the hydrogen was changed to 4.018 g of H2O . What is the empirical formula of the original compound

Answer 1

Empirical formula is: C₂H₅

Step-by-step explanation:

The chemical equation of burning of a compound that conatins only Carbon and Hydrogen is:

CₓHₙ + O₂ → XCO₂ + n/2H₂O

That means the moles of CO₂ produced are the moles of Carbon in the compound and moles of hydrogen are twice moles of water. Empirical formula is the simplest ratio between moles of each element in the compound. Thus, finding molse of C and moles of H we can find empirical formula:

Moles C and H:

Moles C = Moles CO₂:

7.851g CO₂ ₓ (1mol / 44g) = 0.1784 moles CO₂ = Moles C

Moles H = 2 Moles H₂O

4.018g H₂O ₓ (1mol / 18.01g) = 0.2231 * 2 = 0.4417 moles H

Ratio C:H

The ratio between moles of hydrogen and moles of Carbon are:

0.4417 moles H / 0.1784 moles C = 2.5

That means there are 2.5 moles of H per mole of Carbon. As empirical formula must be given only in whole numbers,

Empirical formula is: C₂H₅