Multiple Choice
A sample of an unknown compound was decomposed and found to be composed of 1.36 mol of oxygen, 4.10 mol of hydrogen, and 2.05 mol of carbon. What is the empirical formula of the unknown compound?
3. Chemical Reactions
Empirical Formula
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Determine the empirical formula of a compound that is 49.48% carbon, 5.19% hydrogen, 28.85% nitrogen, and 16.48% oxygen.
A
C2H3NO
B
C3H5N2O2
C
C4H6N2O
D
CH2NO
Verified step by step guidance1
Convert the percentage of each element to grams. Assume you have 100 grams of the compound, so the percentages directly translate to grams: 49.48 g of carbon, 5.19 g of hydrogen, 28.85 g of nitrogen, and 16.48 g of oxygen.
Convert the mass of each element to moles by dividing by their respective molar masses: Carbon (C) has a molar mass of approximately 12.01 g/mol, Hydrogen (H) is about 1.01 g/mol, Nitrogen (N) is about 14.01 g/mol, and Oxygen (O) is about 16.00 g/mol.
Determine the mole ratio of the elements by dividing each element's mole value by the smallest number of moles calculated in the previous step. This will give you a ratio that can be used to determine the empirical formula.
If necessary, multiply the ratios by a whole number to get whole numbers for each element in the empirical formula. This step ensures that the subscripts in the empirical formula are whole numbers.
Write the empirical formula using the whole number ratios as subscripts for each element. The empirical formula represents the simplest whole-number ratio of atoms in the compound.
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