Question

what information does the coefficient tell us in a chemical formula? amount of elements amount of molecules amount of atoms

Explanation:

In chemical formulas, coefficients are numerical values placed before entire chemical formulas (e.g., the 2 in $2H_2O$). They indicate the number of discrete molecules (or formula units for ionic compounds) of that substance. Subscripts, not coefficients, tell the number of atoms, and the count of elements is determined by unique symbols in the formula.

Answer:

B. Amount of molecules