Question

Why are numbers placed before the elements and molecules in a
chemical equation?​

Answer 1

Answer:

the are coefficients for the atom. the tell how many there are.

Explanation:

they tell you how many atoms there are of its type.

ex. 4 C²H³. there are 4 of the c² and h³ (couldn't find a way to use subscript so used the power signs to show.)