A coefficient is a number listed before a compound or atom, telling how many of the compounds are needed so that the Law of Conservation of Mass is obeyed. Given the information provided, how many iron (III) sulfide atoms are there? 4 Fe2S3

See explanation

Explanation:

The law of conservation of mass states that mass can neither be created nor destroyed. This implies that in a chemical reaction, we can only have the same number of atoms of each element on both sides of the reaction equation.

If we write  4Fe2S3 it means that we have;

4 * 2 = 8 atoms of Fe

4 * 3 = 12 atoms of S

8 + 12 = 20 atoms in all

a corroding iron, if that's one of your choices

you need to have a picture of the atom that way we can answer it