# Number of Oxygen Atoms?

The proteins in our bodies are composed of molecules called amino acids. One amino acid is methionine; its molecular formula is C5H11NO2S

The formula mass of Methionine is 149.23g/mol

Question: what is the number of oxygen atoms in a mol of this compound. (Scientific notation)

And can you please show me how to do this?

Relevance
• 8 years ago

1 mol C5H11NO2S * (2 mol O / 1 mol C5H11NO2S) * (6.022*10^23 atoms O / 1 mol O) = 1.2044*10^24 atoms of Oxygen

6.022*10^23 is Avogadro's number, this is the amount of atoms in one mole of anything

Source(s): AP Chemistry
• 8 years ago

It is actually a simple process to find the number of oxygen atoms. Using Avogadro's number will give us the amount of Methionine molecules.

1 mol * (6.02 * 10^23 mol^-1) = 6.02 * 10^23 molecules of Methionine

Methionine is C5H11NO2S, so in 1 molecule we have 2 Oxygen atoms. Simply multiply the molecules of Methionine by 2 to get your final answer:

(6.02 * 10^23) * 2 = 1.20 * 10^24 atoms of Oxygen

Source(s): AP Chemistry student