1. Determine the Gram Formula Mass of a compound 2. Convert between Grams and Moles 3. Convert between Moles and Grams
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1. Determine the Gram Formula Mass of a compound
2. Convert between Grams and Moles
3. Convert between Moles and Grams
Every element has a different atomic mass
12.011g = 1 mole
12.011g/mole
Molar Mass = 207.2 g/mol
1 mole of Lead = 207.2 g
Atomic Mass has a unit of grams/mole
Mass of Magnesium = 24.305 g/mol
1 mole of Magnesium is 24.305 grams
Mass of Mg
24.305 g/mol
Solve the following problem:How many moles are present in 55 g of Magnesium?
Convert 55g of Mg to Moles
55 g Mg
24.305 g Mg
1 mol Mg = 2.26 moles Mg
If 1 mole is 24 g, I predict 55 g is more than 1 mole
1. Cu(NO3)2#1 How many of each
atom are present
#2 What are the masses of each atom?
#3 Multiply the # of atoms by the mass
#4 Add up the amounts and this is the
Gram Formula Mass
Cu = 1
N = 2
O = 6
63.546 g/mol
14.007 g/mol
15.999 g/mol
X
X
X+
187.554 g/mol1 mole of Cu(NO3)2 is 187.554 g
2. KMnO4#1 How many of each
atom are present
K = 1
Mn = 1
O = 4
#2 What are the masses of each atom?
39.098 g/mol
54.938 g/mol
15.999 g/mol #3 Multiply the #
of atoms by the mass
X
X
X
#4 Add up the amounts and this is the
Gram Formula Mass
+
158.032 g/mol1 mole of KMnO4 is 158.032 g
Do the rest as Homework!
Now, take out “Moles and Mass”
Convert 25g of NaCl to Moles
#1 Name the Compound1. NaCl = Sodium Chloride#2 Find the GFMNa = 1 x 22.990 g/mol
Cl = 1 x 35.453 g/mol+
58.443 g/mol#3 Convert grams to moles (Use dimensional
analysis)
25 g NaCl
58.443 g NaCl
1 mol NaCl
Conversion Factor!
= 0.43 moles NaCl
If 1 mole is 58 g, I predict 25 g is less than 1 mole
Convert 405 g of Ag2SO4 to Moles
#1 Name the Compound2.Ag2SO4= Silver (I) Sulfate
#2 Find the GFMAg = 2 x 107.87 g/mol
S = 1 x 32.06 g/mol
O = 4 x 15.999 g/mol+
311.796 g/mol
#3 Convert grams to moles (Use dimensional
analysis)
405 g Ag2SO4
311.796 g Ag2SO4
1 mol Ag2SO4
Conversion Factor!
= 1.30 moles Ag2SO4
If 1 mole is 311 g, I predict 405g is more than 1 mole
Do Not Forget Units
Predictions Help
Section 2 (on back): Converting from Moles to Grams
Simply flip the conversion factor around!
Convert 0.250 moles of NaCl to grams
#1 Name the Compound1. NaCl = Sodium Chloride#2 Find the GFMNa = 1 x 22.990 g/mol
Cl = 1 x 35.453 g/mol+
58.443 g/mol#3 Convert moles to grams(Use dimensional
analysis)
0.250 mol NaCl 58.443 g NaCl
1 mol NaCl
Conversion Factor!
= 14.6 grams NaCl
If 1 mole is 58 g, and I have 0.250 moles, the answer should be less than 58 g of NaCl
Notice moles on bottom!
Convert 1.70 moles of SiO2 to grams
#1 Name the Compound2. SiO2 = Silicon Dioxide#2 Find the GFMSi = 1 x 28.086 g/mol
O = 2 x 15.999 g/mol+
60.084 g/mol#3 Convert moles to grams(Use dimensional
analysis)
1.70 mol SiO2 60.084 g SiO2
1 mol SiO2
Conversion Factor!
= 102.1428 g SiO2
If 1 mole is 60 g, and I have 1.70 moles, the answer should be more than60 g of SiO2
Notice moles on bottom!
1. Determine the GFM of a compound
2. Convert between Grams and Moles
Try the rest as Homework
3. Convert between Moles and Grams
Gram Formula Mass # 3,4,5,6,7
3. Fe2SO4#1 How many of each
atom are present
Fe = 2
S = 1
O = 4
#2 What are the masses of each atom?
55.847 g/mol
32.066 g/mol
15.999 g/mol #3 Multiply the #
of atoms by the mass
X
X
X
#4 Add up the amounts and this is the
Gram Formula Mass
+
207.7576 g/mol1 mole of Fe2SO4 is 207.7576 g
C6H12O6C = 6 x 12.011g/mol
H = 12 x 1.0079g/mol
O = 6 x 15.999g/mol+
180.1548 g/molThis bag is 1 mole or 6.02 x 1023 molecules
of Sucrose
Mass to Moles
Side #1 = 3,4,5
Convert 105.5 g of P2O5 to Moles
#1 Name the Compound3. P2O5= Phosphorus Pentoxide
#2 Find the GFMP= 2 x 30.974 g/mol
O = 5 x 15.999 g/mol
+
141.945g/mol
#3 Convert grams to moles (Use dimensional
analysis)
100.5 g P2O5
141.945 g P2O5
1 mol P2O5
Conversion Factor!
= .70 moles P2O5
If 1 mole is 142 g, I predict 100.5g is less than 1 mole
Convert 538.2 g of (NH4)2CrO4 to Moles
#1 Name the Compound4. (NH4)2CrO4= Ammonium Chromate
#2 Find the GFMN = 2 x 14.0067 g/mol
H = 8 x 1.0079 g/mol
S = 1 x 32.066 g/mol
O = 4 x 15.999 g/mol+
132.14 g/mol
#3 Convert grams to moles (Use dimensional
analysis)
538.2 g (NH4)2CrO4
132.14 g (NH4)2CrO4
1 mol (NH4)2CrO4
Conversion Factor!
= 4.07 moles (NH4)2CrO4
If 1 mole is 132 g, I predict 538.2g is more than 1 mole
Convert 75 g of TiO4 to Moles
#1 Name the Compound5. TiPO4= Titanium Phosphate
#2 Find the GFMTi= 1 x 47.88 g/mol
O = 4 x 15.999 g/mol+
111.878 g/mol
#3 Convert grams to moles (Use dimensional
analysis)
75 g TiO4
111.878 g TiO4
1 mol TiO4
Conversion Factor!
= .67 moles TiO4
If 1 mole is 112 g, I predict 75g is less than 1 mole
Moles to Grams
Side #2 = 3,4,5
Convert .0078 moles of CrPO4 to grams
#1 Name the Compound3. CrPO4 = Chromium Phosphate
#2 Find the GFMCr = 1 x 51.9961 g/mol
P = 1 x 30.9738 g/mol
O = 4 x 15.999 g/mol+
146.968g/mol
#3 Convert moles to grams(Use dimensional
analysis)
.0078 mol CrPO4 146.968 g CrPO4
1 mol CrPO4
Conversion Factor!
= 102.1428 g SiO2
If 1 mole is 145 g, and I have.0078 moles, the answer should be less than 145 g of CrPO4
Notice moles on bottom!
Convert .31 moles of N2O to grams
#1 Name the Compound4. N2O = Dinitrogen Monoxide
#2 Find the GFMN = 2 x 14.00674g/mol
O = 1 x 15.999 g/mol+
44.0129 g/mol#3 Convert moles to grams(Use dimensional
analysis)
.31 mol N2O 44.0129g N2O
1 mol SiO2
Conversion Factor!
= 102.1428 g SiO2
If 1 mole is 44 g, and I have .31 moles, the answer should be less than 44 g of N2O
Notice moles on bottom!
Convert 83.1 moles of I2 to grams
#1 Name the Compound5. I2 = Iodine Gas#2 Find the GFM
I = 2 x 126.904+
253.808 g/mol#3 Convert moles to grams(Use dimensional
analysis)
83.1 mol I2 253.808 g I2
1 mol I2
Conversion Factor!
= 102.1428 g SiO2
If 1 mole is 254 g, and I have 83.1 moles, the answer should be more than 254 g of I2
Notice moles on bottom!
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