Question

When chemists write out reactions, they often place numbers to the left of a chemical formula.

e.g. the first 2 in:

2H+O----> H2O,

What do you call these numbers to the left of chemical formulas?

coefficients,
subscript numbers,
superscript numbers

Answer 1

Answer: The correct answer is coefficients.

Step-by-step explanation:

Coefficients are defined as the numbers which are written in front of the atoms or molecules in a chemical reaction. They represent the number of moles of substance in a chemical reaction.

Subscript numbers are defined as the number of atoms of each element present in a compound.

Superscript numbers are defined as the charges of ions reacting in a chemical reaction.

For Example: Dissociation of sodium carbonate into its ions, the equation follows:

`Na_2CO_3\rightarrow 2Na^++CO_3^(2-)`

The number '2' on the left side written in the subscript of sodium ion represents the number of sodium atoms.

The number '2' on right side written in front of sodium ion represents the number of moles of sodium ions.

The number '(2-)' on right side written in the superscript of carbonate ion represents the charge on carbonate ion.

Hence, the correct answer is coefficients.

Answer 2

The number to the left of a chemical formula is called coefficients

Explanation

Coefficient is the number in front of a chemical formula.

It tell how many molecules of a given formula that are involved in a chemical reaction.

in 2H+O→ H2O the coefficient are 2,1,1

that is, 2 in front of H2

1 in front of O

1 in front of H2O