Which is not true about chemical formulas? If there is only one atom of a certain type, no 'I' is used. The number of each type of atom in a molecule is indicated with a subscript in a chemical formula. A chemical formula expresses the number and types of atoms in a molecule. All chemical formulas are parentheses

All chemical formulas are parentheses

Explanation:

It is not true that all chemical formulas have parentheses. There are several chemical formulas that do not have parentheses.

A chemical formula is used to represent the atoms present within a compound or molecule.

It also specifies the number of atoms present.

Some chemical formula can have parentheses. Some of formulas lacks parentheses.

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.