Counting Atoms

Front

What is an atom?

Back

An atom is the smallest unit of matter that retains the properties of an element.

Front

What is a coefficient in a chemical equation?

Back

A coefficient is a number placed in front of a chemical formula to indicate how many molecules or atoms of that substance are present.

Front

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

Back

Count the subscripts next to each element. If there is no subscript, it means there is one atom of that element.

Front

What does a subscript indicate in a chemical formula?

Back

A subscript indicates the number of atoms of the element in the molecule.

Front

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

Back

There are 2 hydrogen atoms.

Front

In the formula C₆H₁₂O₆, how many total atoms are there?

Back

There are 24 total atoms (6 Carbon + 12 Hydrogen + 6 Oxygen).

Front

What is the significance of parentheses in a chemical formula?

Back

Parentheses indicate that the atoms inside are grouped together and the subscript outside applies to all atoms within the parentheses.

Front

How many atoms of Calcium are in the equation H₃O₅CaCl₇?

Back

1

Front

How many atoms of Carbon are in the equation HʒC₅O₄?

Back

5

Front

How many atoms of Iron are in the equation C₂HAu₅?

Back

0