Final answer:
The formula for caffeine is C8H10N4O2, which includes the exact number of each atom in the molecule, and it also serves as its empirical formula, as the ratio cannot be reduced.
Step-by-step explanation:
The formula for caffeine, which contains 8 atoms of carbon, 10 atoms of hydrogen, 4 atoms of nitrogen, and 2 atoms of oxygen is C8H10N4O2. When writing a chemical formula, the convention is to list the elements in a specific order, generally starting with carbon and hydrogen, followed by other elements in alphabetical order. This is why nitrogen (N) comes before oxygen (O) in the formula for caffeine.
The molecular formula conveys the actual number of atoms of each element in a molecule of a compound, which for caffeine is precisely the composition mentioned. Remember that empirical formulas are the simplest whole number ratios of elements in a compound; however, in this case, the molecular formula itself is also the empirical formula for caffeine since the atomic ratio cannot be simplified further.