Multiple Choice
A 4.386 g compound of hydrogen, carbon, and oxygen was burned in 9.389 g of oxygen, producing 6.184 g of carbon dioxide and 3.789 g of water. What is the empirical formula of the original sample?
3. Chemical Reactions
Empirical Formula
Multiple Choice
A compound contains 1.0 g of sulfur (S) and 1.5 g of oxygen (O). What is the empirical formula of the compound?
A
S_2O
B
SO_2
C
SO
D
S_2O_3
Verified step by step guidance1
Determine the number of moles of each element by dividing the given mass by the atomic mass of the element. Use the atomic masses: sulfur (S) = 32.06 g/mol and oxygen (O) = 16.00 g/mol. Calculate moles of sulfur as \(\frac{1.0\ \text{g}}{32.06\ \text{g/mol}}\) and moles of oxygen as \(\frac{1.5\ \text{g}}{16.00\ \text{g/mol}}\).
Find the simplest whole number mole ratio by dividing both mole values by the smaller number of moles calculated in the previous step. This will give the relative number of atoms of each element in the compound.
If the mole ratio is not close to whole numbers, multiply both ratios by the smallest integer that converts them into whole numbers (e.g., 2, 3, 4, etc.). This step ensures the empirical formula has whole number subscripts.
Write the empirical formula by using the whole number mole ratios as subscripts for each element. For example, if the ratio of sulfur to oxygen is 1:2, the empirical formula is \(\mathrm{SO_2}\).
Double-check your mole ratio and empirical formula to ensure it matches the mass data and that the subscripts are the smallest whole numbers possible.
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