Question

Give the number of atoms of the specified elements in a formula unit of each of the following compounds


Hydrogen in ammonium benzoate - C6H5COONH4

Would the answer be
9 Hydrogen x 6.022*10^23 =
5.42*10^24 hydrogen atoms ??

Answer 1

No, but that is a great way to be thinking like a chemist. A chemical formula is a way to express what atoms are in a chemical compound at its simplest form. In ammonium benzoate there are (6+1) 7 atoms of carbon, (5+4) 9 atoms of hydrogen, 2 atoms of oxygen, 1 atom of nitrogen.
As Wiki states "The chemical formula identifies each constituent element by its chemical symbol and indicates the number of atoms of each element found in each discrete molecule of that compound. If a molecule contains more than one atom of a particular element, this quantity is indicated using a subscript after the chemical symbol and also can be combined by more chemical elements. For example, methane, a small molecule consisting of one carbon atom and four hydrogen atoms, has the chemical formula CH4. The sugar molecule glucose has six carbon atoms, twelve hydrogen atoms and six oxygen atoms, so its chemical formula is C6H12O6."

Answer 2

Your answer would be correct if the question had asked, "How many hydrogen atoms in a MOLE of the substance?"