Counting Atoms and Molar Mass (II)
Directions: Fill in the data table with the correct data.
Consider the compound ammonium chloride: NH4Cl
Atoms
N=1
H=4
Cl = 1
Mass
x
x
x
Total
14
1
35
Molar Mass
=
=
=
=
14
4
35
53 g/mol
How many molecules of ammonium chloride are in 22 grams?
22 g
mol
1
53 g
6.02 x 1023
molecules
2.50 x 1023 molecules
1 mol
Consider the compound barium ferrite: BaFe2O4
Atoms
Ba = 1
Fe = 2
O=4
Mass
137
56
16
Molar Mass
x
x
x
=
=
=
=
Total
137
112
64
313 g/mol
How many molecules of barium ferrite are in 2.2 grams?
2.2 g
1
mol
313 g
6.02 x 1023
molecules
1 mol
4.23 x 1021 molecules
Consider the compound lithium perchlorate: LiClO4
Atoms
Li = 1
Cl = 1
O=4
Mass
7
35
16
Molar Mass
x
x
x
=
=
=
=
Total
7
35
64
106 g/mol
How many molecules of lithium perchlorate are in 2.5 grams?
2.5 g
mol
1
106 g
6.02 x 1023
molecules
1.42 x 1022 molecules
1 mol
Consider the compound iron (III) nitrate: Fe(NO3)3(H2O)9
Atoms
Fe = 1
N=3
H = 18
O = 18
x
x
x
x
Mass
56
14
1
16
Molar Mass
=
=
=
=
=
Total
56
42
18
288
404 g/mol
How many molecules of iron (III) nitrate are in 10.5 grams?
10.5 g
1
1 mol
404 g
6.02 x 1023
molecules
1 mol
4.23 x 1021 molecules
Symbol
Atomic #
Mass #
# Protons
# Electrons
# Neutrons
Hg
80
200
80
80
120
Mo
42
96
42
42
54
N
7
14
7
7
7
Pb
82
207
82
82
125
Ignore
Atomic # is the # of protons in the nucleus
Mass # is the number of protons + neutrons
The number of neutrons is the mass # - the # of protons
If the atom has no charge, then the #protons = the #electrons