Counting Atoms in Chemical Formulas

Front

What is a chemical formula?

Back

A chemical formula is a way of expressing the number and type of atoms in a molecule using symbols and numbers.

Front

How do you count atoms in a chemical formula?

Back

To count atoms, look at the subscripts in the formula. The subscript indicates the number of atoms of that element in the molecule.

Front

What does a subscript of '2' next to an element symbol mean?

Back

It means there are two atoms of that element in the molecule.

Front

In the formula H2O, how many total atoms are there?

Back

There are 3 total atoms: 2 Hydrogen atoms and 1 Oxygen atom.

Front

What is the significance of parentheses in chemical formulas?

Back

Parentheses indicate that the atoms inside them are grouped together and may be multiplied by a subscript outside the parentheses.

Front

In Al(OH)3, how many Oxygen atoms are there?

Back

There are 3 Oxygen atoms, as the OH group is multiplied by 3.

Front

What elements are present in H2COCH2?

Back

The elements present are Hydrogen (H), Carbon (C), and Oxygen (O).

Front

How many Hydrogen atoms are in 4H2O?

Back

There are 8 Hydrogen atoms in 4H2O.

Front

What is the formula for sulfuric acid?

Back

The formula for sulfuric acid is H2SO4.

Front

In H2SO4, how many Sulfur atoms are there?

Back

There is 1 Sulfur atom in H2SO4.