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Quantitative Information
There are two types of numbers that give us quantitative information about atoms and molecules:
1. COEFFICIENT: A big number in front of the symbol that represents how many molecules there are 3H20: The coefficient is three. This means that there are three molecules of H20.
2. SUBSCRIPT: A small number to the bottom right of the symbol that represents how many atoms there are (within the molecule)
HO3: The subscript is three. This means that there are three O atoms in the molecule.
When the subscript is outside the parentheses, the subscript applies to all the atoms inside the
parentheses.
(CO)2 means C2O2.
2K3 means there are two molecules, each containing three ‘K’s
(‘K’-‘K’-‘K’ and ‘K’-‘K’-‘K’). The coefficient is two and the subscript is three.
UNIT 6: MATH IN CHEMISTRY © 206