Counting Atoms - Molecular Formulas

Front

What is a molecular formula?

Back

A molecular formula shows the number and type of atoms in a molecule, represented by chemical symbols and subscripts.

Front

How do you count the total number of atoms in a molecular formula?

Back

Add the subscripts of all elements in the formula. For example, in C2H6O, there are 2 + 6 + 1 = 9 total atoms.

Front

What does the subscript in a chemical formula indicate?

Back

The subscript indicates the number of atoms of the element present in the molecule. For example, in H2O, the '2' indicates there are 2 hydrogen atoms.

Front

What is the molecular formula for propane?

Back

C3H8.

Front

How many atoms are in the compound C2H8O?

Back

There are 11 total atoms (2 Carbon, 8 Hydrogen, 1 Oxygen).

Front

What is the correct formula for a compound with 1 nickel atom and 2 fluorine atoms?

Back

NiF2.

Front

In the formula H2SO4, how many sulfur atoms are present?

Back

There is 1 sulfur atom.

Front

What is the number of sodium atoms in Na2CO3?

Back

There are 2 sodium atoms.

Front

What does the formula CH4 represent?

Back

Methane, which has 1 carbon atom and 4 hydrogen atoms.

Front

How do you determine the number of oxygen atoms in a compound like H2O?

Back

The subscript '1' is implied for oxygen, so there is 1 oxygen atom in H2O.