Atoms/Molecules/Moles/Mass/Volume
Method 1 - Cancel method
Method 2 - Formula
Method 3 - Ratio
I.
Atoms
moles
When dealing with something that is NOT a molecule
i.e.,
Ni - 1 atom (not a molecule)
2 Ni - 2 atoms
go directly from atoms
moles using Avagadro's number
Example 1 Change 7.5 x 1012 atoms C to moles
Example 2 Change 8.0 x 10-6 moles of Boron to atoms
II.
moles
mass
Example 1 Change 4.35 g of H2 SO4 to moles
Example 2 Change 3.8 moles of Ca3(P04)2 to mass.
III.
molecules
moles
Example 1 Change 1.73 moles of Al2O3 to molecules
Example 2 Change 4.7 molecules of CH3COOH to moles.
IV.
Atoms
molecules
moles
mass
Example 1 Change 67.0 g of oxygen gas (O2) to atoms
Example 2 Change 4.5 x 1015 atoms of nitrogen (N2) to mass in grams
V.
moles
volume
Example 1 Change 7.3 x 106 moles CO2(g) to a volume in liters at STP.
Example 2 Change 40.5 L of HBr(g) to moles at STP.
VI.
mass
moles
volume
Example 1 Change 2.46 x 10-4 kg HCl(g) to a volume in liters at STP.
Example 2 Change 1.2 x 105 L of CH3(g) to a mass in grams.
EXERCISES
I.
Change the following from atoms to moles.
5.50 x 103
1.
Fe(s)
atoms
2.
3.
7.3 atoms
9.98 x 1024
Cu(s)
atoms
II.
Xe(s)
Change from moles to atoms
1.
2.
3.
1.87 x 10-5 mol
4.5 mol
7.7 x 10-24 mol
Li(s)
Pb(s)
N2(g)
III.
Change from moles to mass in grams
1.
2.
3.
H2SO4(aq)
0.534 mol
4.15 x 108 mol
Na2CrO4(s)
2.46 x 1024 mol
Ba(SCN)2(aq)
IV.
Change from mass to moles
1.
2.
3.
71g
0.049 g
2.35 x 10-2 kg
PCl5
phosphorous
A12(C03)3
V.
Change from molecules to moles
1.
2.
3.
VI.
1.04 x 1024
molecules
5.5 x 1026
molecules
6.15 molecules
CCl4
SO3
NI3
Change from moles to molecules
1.
2.
8.8 x 10-2 mol
HBr
2.3 mol
3.
3.024 mol
SrH2
NaOH
VII.
VIII.
Change from volume to moles
1. 0.120 L SO2(g) at STP
2.
1.6 x 10-18 mL HBr(g) at STP
3. 3.125 kL Ar(g) at STP
Change from moles to volume in litres at STP
1.
2.
0.523 mol
1.05 x 10-8
mol
3.
CO2(g)
HCl(g)
63.7 mmol
O2(g)
IX.
Make the following changes
1.
3.16 x 107 g of CuSO4 to molecules
2.
9.57 x 1015 atoms sulphur to mass in grams
3.
8.48 x 10-4 molecules of BF3(g) to volume in litres at STP
4.
7.25 L of NH3(g) at STP to atoms
5.
4.0 atoms of He to mass in grams.