Counting Atoms in Chemical Formulas

Front

What is a chemical formula?

Back

A chemical formula is a way of expressing the composition of a substance using symbols for its constituent elements and numerical subscripts to indicate the number of atoms of each element.

Front

What does a subscript in a chemical formula indicate?

Back

A subscript indicates the number of atoms of the element that it follows in a chemical formula.

Front

How many atoms of Sodium (Na) are in the formula 3NaCl?

Back

3

Front

How many atoms of Chlorine (Cl) are in the formula 3NaCl?

Back

3

Front

In the formula 10MgCl2, how many Magnesium (Mg) atoms are present?

Back

10

Front

In the formula 10MgCl2, how many Chlorine (Cl) atoms are present?

Back

20 (since there are 2 Cl atoms for each Mg atom, and there are 10 Mg atoms).

Front

How many total atoms are in the formula CH4COOH2?

Back

10 total atoms (2 Carbon, 6 Hydrogen, 2 Oxygen).

Front

What is the correct chemical formula for one carbon atom and two oxygen atoms?

Back

CO2.

Front

What is the significance of the coefficients in a chemical formula?

Back

Coefficients indicate the number of molecules or moles of the compound present.

Front

How do you determine the total number of atoms in a compound?

Back

Add the number of atoms of each element, taking into account the subscripts and coefficients.