1. Gram to moles to moles to Grams pg 8
(Use molar mass—mole ratio—molar mass)
23 g CO
?g Fe
1. For this reaction: Fe3O4 + 4 CO  3 Fe + 4 CO2
a. How many grams of Fe are produced from 23 grams of CO?
23 g CO
1 mol CO
28.0 g CO
= 0.82 mol CO
0.82 mol CO
3 mol Fe
4 mol CO
= 0.62 mol Fe
55.8 g Fe
1 mol Fe
= 34.6 g Fe
0.62 mol Fe

2. = = Fe3O4 + 4 CO  3 Fe + 4 CO2 3 mol Fe 4 mol CO 167.4 g Fe 112 g CO
3 x 55.8 = g Fe
4 x 28 = 112 g CO
167.4 g Fe
112 g CO =
? g Fe
23 g CO
= 34.6 g Fe

3. 0.95 g Fe3O4 1 mol Fe3O4 231.4 g Fe3O4 = 0.0041 mol Fe3O4
? g CO2
For this reaction: Fe3O4 + 4 CO  3 Fe + 4 CO2
b. How many grams of CO2 are produced from 0.95 grams of Fe3O4?
0.95 g Fe3O4
1 mol Fe3O4
231.4 g Fe3O4
= mol Fe3O4
mol Fe3O4
4 mol CO2
1 mol Fe3O4
= mol CO2
mol CO2
44.0 g CO2
1 mol CO2
= 0.72 g CO2

4. = = 1 mol Fe3O4 4 mol CO2 231.4 g Fe3 O4 176 g CO2
For this reaction: Fe3O4 + 4 CO  3 Fe + 4 CO2
b. How many grams of CO2 are produced from 0.95 grams of Fe3O4?
1 mol Fe3O4
4 mol CO2 =
231.4 g Fe3 O4
176 g CO2
1 x [3 x x 16]
4 x [1 x x 16]
231.4 g Fe3O4
176 g CO2 =
0.95 g Fe3O4
? g CO2
= 0.72 g CO2

5. 7.85 g PbO 1 mol PbO 223.2 g PbO = 0.0352 mol PbO 0.0352 mol PbO
2. For this reaction: 6 PbO + O2  2 Pb3O4
a. How many grams of Pb3O4 are produced from 7.85 grams of PbO?
7.85 g PbO
1 mol PbO
223.2 g PbO
= mol PbO
mol PbO
2 mol Pb3O4
6 mol PbO
= mol Pb3O4
mol Pb3O4
685.6 g Pb3O4
1 mol Pb3O4
= 8.0 g Pb3O4

6. = = 6 mol PbO 2 mol Pb3O4 1339.2 g PbO 1371.2 g Pb3O4 6 x [207.2 + 16]
2. For this reaction: 6 PbO + O2  2 Pb3O4
a. How many grams of Pb3O4 are produced from 7.85 grams of PbO?
6 mol PbO
2 mol Pb3O4 =
g PbO
g Pb3O4
6 x [ ]
2 x [3 x x 16]
g PbO g Pb3O4 =
7.85 g PbO
? g Pb3O4
= 8.0 g Pb3O4

7. 1.75 g O2 1 mol O2 32.0 g O2 = 0.0547 mol O2 0.0547 mol O2 6 mol PbO
2. For this reaction: 6 PbO + O2  2 Pb3O4
b. How many grams of PbO must react with 1.75 grams of O2?
1.75 g O2
1 mol O2
32.0 g O2
= mol O2
mol O2
6 mol PbO
1 mol O2
= mol PbO
0.328 mol PbO
223.2 g PbO
1 mol PbO
= 73.2 g PbO

8. = = 6 mol PbO 1 mol O2 1339.2 g PbO 32.0 g O2 6 x [207.2 + 16]
2. For this reaction: 6 PbO + O2  2 Pb3O4
b. How many grams of PbO must react with 1.75 grams of O2?
6 mol PbO
1 mol O2 =
g PbO
32.0 g O2
6 x [ ]
[2 x 16]
g PbO 32.0 g O2 =
? g PbO
1.75 g O2
= 73.2 g PbO

9. 17 g Al 1 mol Al 27.0 g Al = 0.63 mol Al 0.63 mol Al 2 mol Al2O3
3. For this reaction: 4 Al + 3 O2  2 Al2O3
a. How many grams of Al2O3 will be formed from 17 grams of Al reacting?
17 g Al
1 mol Al
27.0 g Al
= 0.63 mol Al
0.63 mol Al
2 mol Al2O3
4 mol Al
= 0.31 mol Al2O3
0.31 mol Al2O3
102.0 g Al2O3
1 mol Al2O3
= 31.6 g Al2O3

10. = = 4 mol Al 2 mol Al2O3 108.0 Al 204.0g Al2O3 4 x [27.0]
3. For this reaction: 4 Al + 3 O2  2 Al2O3
a. How many grams of Al2O3 will be formed from 17 grams of Al reacting?
4 mol Al
2 mol Al2O3 =
108.0 Al
204.0g Al2O3
4 x [27.0]
2 x [2 x x 16]
108.0 g Al
204.0 g Al2O3 =
17 g Al
? g Al2O3
= 32.1 g Al2O3

11. 12 g Al 1 mol Al 27.0 g Al = 0.44 mol Al 0.44 mol Al 3 mol O2 4 mol Al
3. For this reaction: 4 Al + 3 O2  2 Al2O3
b. How many grams of O2 are needed to react with 12 grams of Al?
12 g Al
1 mol Al
27.0 g Al
= 0.44 mol Al
0.44 mol Al
3 mol O2
4 mol Al
= 0.33 mol O2
0.33 mol O2
32.0 g O2
1 mol O2
= 10.6 g O2

12. = = 4 mol Al 3 mol O2 108.0 g Al 96.0 g O2 4 x [27.0] 3 x [2 x 16]
3. For this reaction: 4 Al + 3 O2  2 Al2O3
b. How many grams of O2 are needed to react with 12 grams of Al?
4 mol Al
3 mol O2 =
108.0 g Al
96.0 g O2
4 x [27.0]
3 x [2 x 16]
108.0 g Al
96.0 g O2 =
12 g Al
? g O2
= 10.7 g O2

13. 1.25 g NH3 1 mol NH3 17.0 g NH3 = 0.0735 mol NH3 0.0735 mol NH3
4. For this reaction: 4 NH O2  4 NO + 6 H2O
a. How many grams of O2 are needed to react with 1.25 grams of NH3?
1.25 g NH3
1 mol NH3
17.0 g NH3
= mol NH3
mol NH3
5 mol O2
4 mol NH3
= mol O2
0.092 mol O2
32.0 g O2
1 mol O2
= 2.9 g O2

14. = = 4 mol NH3 5 mol O2 68.0 g NH3 160.0 g O2 4 x [1 x 14 + 3 x 1]
4. For this reaction: 4 NH3 + 5 O2  4 NO + 6 H2O
a. How many grams of O2 are needed to react with 1.25 grams of NH3?
4 mol NH3
5 mol O2 =
68.0 g NH3
160.0 g O2
4 x [1 x x 1]
5 x [2 x 16]
68.0 g NH3
160.0 g O2 =
1.25 g NH3
? g O2
= 2.9 g O2

15. 7.65 g O2 1 mol O2 32.0 g O2 = 0.239 mol O2 0.239 mol O2 6 mol H2O
4. For this reaction: 4 NH3 + 5 O2  4 NO + 6 H2O
b. How many grams of H2O are produced from 7.65 grams of O2?
7.65 g O2
1 mol O2
32.0 g O2
= mol O2
0.239 mol O2
6 mol H2O
5 mol O2
= mol H2O
0.287 mol H2O
18.0 g H2O
1 mol H2O
= 5.2 g H2O

16. = = 6 mol H2O 5 mol O2 108.0 g H2O 160.0 g O2 6 x [2 x 1 + 1 x 16]
4. For this reaction: 4 NH3 + 5 O2  4 NO + 6 H2O
b. How many grams of H2O are produced from 7.65 grams of O2?
6 mol H2O
5 mol O2 =
108.0 g H2O
160.0 g O2
6 x [2 x x 16]
5 x [2 x 16]
108.0 g H2O
160.0 g O2 =
? g H2O
7.65 g O2
= 5.2 g H2O