Question

What is the formula of the following compound names? Hydrochloric acid, Copper (ll) choride, Dinitrogen pentoxide, Aluminum sulfide, and Iron (ll) nitride

Answer 1

There are 3 nomenclature types, so you have to be attentive of which one it is:

Hydrochloric acid: It is a hydracid, it is composed only of the elements present in the name (hydrogen and chloride).

`HCl\text{ }\rightarrow\text{ The oxidation number of the halogen is always -1}`

Copper (II) chloride: It's a salt composed of a metal and a halogen. The oxidation number of the halogen is -1 also in this case. This type of nomenclature tells us which is the oxidation number of the copper also, and it is the number between the parenthesis (+2).

`Cu^(+2)Cl^-\text{ }\rightarrow\text{ CuCl}_2`

Dinitrogen pentoxide: This type of nomenclature shows the number of atoms of each element present in the formula (di is 2, and penta is 5):

`N_2O_5`

Aluminum sulfide: In the sulfides, there's the element named plus sulfur (with an oxidation number of -2). The aluminum only has +3 in its oxidation number:

`Al^(+3)S^(-2)\text{ }\rightarrow\text{ Al}_2S_3`

Iron (II) nitride: In this case, the nitride means it's going to be nitrogen (with an oxidation number of -3) and the other element, in this case, iron (with an oxidation number of +2, as it says in the name):

`Fe^(+2)N^(-3)\text{ }\rightarrow\text{ Fe}_3N_2`