ATOMS & MOLECULES

1. for monoatomic elements
a molecule= an atom

2. diatomic elements:
a molecule an atom
Cl2 Cl

Molecules of compounds:
2 hydrogen atoms}
1 oxygen atom } 1 molecule

EXAMPLE:
write the formula for ammonium carbonate:
(NH4)2 CO3
2-N
8-H
1-C
3-O
= 14 atoms

moles<--->molecules
6.02x10^23 molecules
---------------------
1 mol

**HOW MANY MOLECULES ARE IN A 0.25MOL SAMPLE OF CO2?
0.25<----> molecules
0.25molx 6.02x10^23molecules= 1.51x 10^23 molecules
----------
1 mol

1.51x10^23 carbon atoms
3.02x10^23 oxygen atoms

**5.1772x10^24 molecules of water= ??? moles
5.1772x10^24 x1mol}
------------------}= 8.6mol
6.02x10^23}