a sample of a compound that contains only the elements C, H and N is completely burned in O2 to produce 44g of CO2, 45g of H2O, and some NO2. A possible empirical formula of the compound is A. CH2N B. CH5N C. C2H5N D. C3H3N2

B. CH₅N

Explanation:

The combustion reaction of a compound CₐHₓNₙ with O₂ is:

CₐHₓNₙ + O₂ → a CO₂ + X/2 H₂O + n NO₂

Where 1 mole of CₐHₓNₙ with an excess of O₂ produce a moles of CO₂, X/2 moles of H₂O and n moles of NO₂

Thus, you need to convert the mass of CO₂ and H₂O to moles to find the C:H ratio and determine a possible empirical formula thus:

Moles CO₂ (Molar mass 44g/mol):

44g ₓ (1mol / 44g) = 1 mole CO₂ = 1 mole C

Mole of H₂O (Molar mass 18g/mol):

45g ₓ (1 mol / 18g) = 2.5 moles H₂O = 5 moles H

Thus, in the compound you have 5 moles of H per mole of C, and a possible empirical formula is:

The only structure that meet this C:H ratio