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COMPOUNDS
A. Matter is made up of (from smallest to largest)
1) atom – smallest part of an element that has that element’s
characteristics.
2) element – a pure substance made up of only one type of atom
3) molecule – two or more elements (same or different) bonded
together
4) compound – two or more different elements combined
B. Compounds are represented with chemical formulas
1) formulas are made up of element symbols and numbers
2) the numbers are subscript. This tells you the number of atoms
needed to make this compound.
3) If there is a (large) number in front of the compound, that tells
you how many molecules of that compound there is
4) Examples:
a) H2O
hydrogen = 2
oxygen = 1
b) C6H12O6
carbon = 6
hydrogen = 12
oxygen = 6
c) Na(OH)2
sodium = 1
oxygen = 2
hydrogen = 2
d) Na(NH4)3
sodium = 1
nitrogen = 3
hydrogen = 12
e) 3CO2
carbon = 3
oxygen = 6
f) 3Na(OH)2
sodium = 3
oxygen = 6
hydrogen = 6
* If there is a # in front of the compound, multiply everything by that
number
** If there is a parenthesis, multiply only what is in the parenthesis by the
subscript # right after the parenthesis