1. Chapter 5 Chemical Reactions and Quantities
Mole Relationships in Chemical Equations
LecturePLUS Timberlake 99

2. LecturePLUS Timberlake 99
Mole-Mole Factors
Show the mole-to-mole ratio between two of the substances in a balanced equation
Use the coefficients of two substances in the equation
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3. LecturePLUS Timberlake 99
Writing Mole Factors
4 Fe O Fe2O3
Fe and O mole Fe and 3 mole O2
3 mole O mole Fe
Fe and Fe2O3 4 mole Fe and 2 mole Fe2O3
2 mole Fe2O3 4 mole Fe
O2 and Fe2O3 3 mole O2 and 2 mole Fe2O3
2 mole Fe2O3 3 mole O2
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4. LecturePLUS Timberlake 99
Learning Check S1
3 H2(g) N2(g) NH3(g)
A. A mole factor for H2 and N2 is
1) 3 mole N ) 1 mole N ) 1 mole N2
1 mole H mole H mole H2
B. A mole factor for NH3 and H2 is
1) 1 mole H ) 2 mole NH ) 3 mole N2
2 mole NH mole H mole NH3
LecturePLUS Timberlake 99

5. LecturePLUS Timberlake 99
Solution S1
3 H2(g) N2(g) NH3(g)
A. A mole factor for H2 and N2 is
2) 1 mole N2
3 mole H2
B. A mole factor for NH3 and H2 is
2) 2 mole NH3
LecturePLUS Timberlake 99

6. Chemical Calculations
4 Fe O Fe2O3
How many moles of Fe2O3 are produced when 6.0 moles O2 react?
6.0 mole O2 x 2 mole Fe2O3 = 4.0 mole Fe2O3
3 mole O2
LecturePLUS Timberlake 99

7. LecturePLUS Timberlake 99
Learning Check S2
4 Fe O Fe2O3
How many moles of Fe are needed to react with 12.0 mole of O2?
1) mole Fe
2) mole Fe
3) mole Fe
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8. LecturePLUS Timberlake 99
Solution S2
4 Fe O Fe2O3
12.0 mole O2 x mole Fe = mole Fe
3 mole O2
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9. LecturePLUS Timberlake 99
Learning Check S 3
4 Fe O Fe2O3
How many grams of O2 are needed to produce mole of Fe2O3?
1) g O2
2) g O2
3) g O2
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10. LecturePLUS Timberlake 99
Solution S 3
2) g O2
0.400 mole Fe2O3 x 3 mole O2 x g O2
2 mole Fe2O3 1 mole O2
= g O2
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11. LecturePLUS Timberlake 99
Mass of A Reaction
The reaction between H2 and O2 produces 13.1 g of water. How many grams of O2 reacted?
Write the equation
H2 (g) O2 (g) H2O (g)
Balance the equation
2 H2 (g) O2 (g) 2 H2O (g)
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12. LecturePLUS Timberlake 99
Organize data
mole bridge
2 H2 (g) O2 (g) 2 H2O (g)
? g g
Plan g H2O mole H2O mole O O2
Setup
13.1 g H2O x 1 mole H2O x 1 mole O2 x g O g H2O 2 mole H2O 1 mole O2
= g O2
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13. LecturePLUS Timberlake 99
Points to Remember
1. Read an equation in moles
2. Convert given amount to moles
3. Use mole factor to give desired moles
4. Convert moles to grams
grams (given) grams (desired)
moles (given) moles (desired)
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14. LecturePLUS Timberlake 99
Learning Check S 4
How many grams of O2 are need to react grams of Na in the reaction
4 Na O Na2O
Complete the set up:
50.0 g Na x 1 mole Na x ________ x _______
23.0 g Na
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15. LecturePLUS Timberlake 99
Solution S 4
4 Na O Na2O
50.0 g Na x 1 mole Na x 1 mole O2 x g
23.0 g Na mole Na mole O2
= g O2
LecturePLUS Timberlake 99

16. LecturePLUS Timberlake 99
Learning Check S5
Acetylene gas C2H2 burns in the oxyactylene torch for welding. How many grams of C2H2 are burned if the reaction produces 75.0 g of CO2?
2 C2H O CO H2O
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17. LecturePLUS Timberlake 99
Solution S5
2 C2H O CO H2O
75.0 g CO2 x 1 mole CO2 x 2 mole C2H2 x 26.0 g C2H2
44.0 g CO mole CO mole C2H2
= g C2H2
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18. Pathways for Problems Using Equations
Given (A) Find (B)
grams (A) grams (B)
moles (A) moles (B)
particles (A) particles (B)
LecturePLUS Timberlake 99

19. Pathways for Problems Using Equations
Given (A) Find (B)
grams (A) grams (B)
molar molar
mass (A) mass (B)
coefficients
moles (A) moles (B)
Avogadro's Avogradro’s
number number
particles (A) particles (B)
LecturePLUS Timberlake 99