Answer:
Step 1: Converting the percentages to grams
Assuming we have 100 grams of the compound, we can calculate the mass of each element as follows:
Carbon: 40.0 grams (40.0% of 100 grams)
Hydrogen: 6.67 grams (6.67% of 100 grams)
Oxygen: 53.33 grams (53.33% of 100 grams)
Step 2: Finding the moles of each element
To find the number of moles of each element, we need to divide the mass of each element by its molar mass.
Carbon: molar mass of carbon = 12.01 g/mol
moles of carbon = 40.0 g / 12.01 g/mol = 3.33 mol
Hydrogen: molar mass of hydrogen = 1.01 g/mol
moles of hydrogen = 6.67 g / 1.01 g/mol = 6.61 mol
Oxygen: molar mass of oxygen = 16.00 g/mol
moles of oxygen = 53.33 g / 16.00 g/mol = 3.33 mol
Step 3: Finding the ratio of the moles in whole numbers to construct the empirical formula
The empirical formula gives the simplest whole-number ratio of atoms in a compound. To find it, we need to divide each of the mole values by the smallest one, and then round to the nearest whole number:
Carbon: 3.33 mol / 3.33 mol = 1.00 (rounded to nearest whole number)
Hydrogen: 6.61 mol / 3.33 mol = 1.98 (rounded to nearest whole number)
Oxygen: 3.33 mol / 3.33 mol = 1.00 (rounded to nearest whole number)
The empirical formula is therefore CH2O.}