Counting Atoms in a Chemical Formula

How many atoms of Hydrogen are in H₂O

• 1

• 2

• 3

• more than 3

How many different elements are present in H₂COCH₂

• 5

• 4

• 3

• 2

Calculate the number of Oxygen atoms in Al(OH)₃

• 1

• 2

• 3

• 4

The ______ are numbers found on the lower right-hand side of an element symbol.

• Coefficient

• Exponent

• Multiplier

• Subscript

Coefficients in chemical formulas...

• Multiply just the first atom

• Add to the subscripts at the end of the molecule

• Multiply elements without subscripts

• Multiply EVERYTHING!

4CF₂Cl₂

• C = 4, F = 4, Cl = 2

• C = 1, F = 8, Cl = 8

• C = 4, F = 8, Cl = 8

• C = 1, F = 4, Cl = 8

C₃H₅(NO₃)₃

• C = 3, H = 5, N = 3, O = 9

• C = 3, H = 5, N = 1, O = 9

• C = 9, H = 15, N = 3, O = 9

• C = 9, H = 15, N = 1, O = 3

H₂SO₄

• H = 2, S = 4, O = 4

• H = 2, S = 1, O = 4

• H = 8, S = 4, O = 4

• H = 2, SO = 4

How many different elements are present in this molecule?

3 NH₄C₂H₃O₂

• 15

• 36

• 5

• 4

A ______ is a number written in front of a chemical formula.

• Coefficient

• Subscript

• Exponent

• Coordinator