Transcript Gravimetric Stoichiometry Brant

Gravimetric Stoichiometry
Stoichiometry
a measure of the relative proportions of the elements that take part in a
chemical reaction
4 Al (s) + 3 O2 (g) = 2 Al2O3 (s)
6.49 g
? mol
26.98 g/mol
Stoichiometry
a measure of the relative proportions of the elements that take part in a
chemical reaction
4 Al (s) + 3 O2 (g) = 2 Al2O3 (s)
6.49 g
? mol
26.98 g/mol
nAl = m/M = 6.49g/26.98g/mol = 0.2405485 mol
nO2 = nAl x mole ratio
Stoichiometry
a measure of the relative proportions of the elements that take part in a chemical
reaction
4 Al (s) + 3 O2 (g) = 2 Al2O3 (s)
6.49 g
? mol
26.98 g/mol
nAl = m/M = 6.49g/26.98g/mol = 0.2405485 mol
nO2 = nAl x mole ratio
0.2405485 mol Al x 3 mol O2
4 mol Al
0.1804114 mol O2
0.180 mol O2
*example from http://www.cdli.ca/courses/chem2202/unit01_org02_ilo03/b_activity.html
Gravimetric Stoichiometry
Gravimetric stoichiometry is stoichiometry with the answer expressed in mass.
nAl2O3 = nO2 x mole ratio
=0.1804 mole O2 x 2 mol Al2O3
3 mol O2
= 0.1202666 mol Al2O3
Gravimetric Stoichiometry
Gravimetric stoichiometry is stoichiometry with the answer expressed in mass.
nAl2O3 = nO2 x mole ratio
=0.1804 mole O2 x 2 mol Al2O3
3 mol O2
= 0.1202666 mol Al2O3
mAl2O3 = n x M = 0.1202666 mol x 101.96 g/mol
=12.262389g
=12.26g of Al2O3
*example from http://www.cdli.ca/courses/chem2202/unit01_org02_ilo03/b_activity.html
Gravimetric Stoichiometry
1) Which word is most closely associated with meaning of the term gravimetric?
A ) density
B ) mass
C ) mole
D ) volume
2) Which device is best suited to obtaining a specific mass of a chemical species?
A ) balance
B ) beaker
C ) flask
D ) graduated cylinder
Gravimetric Stoichiometry
1) Which word is most closely associated with meaning of the term gravimetric?
A ) density
B ) mass
C ) mole
D ) volume
2) Which device is best suited to obtaining a specific mass of a chemical species?
A ) balance
B ) beaker
C ) flask
D ) graduated cylinder
Gravimetric Stoichiometry
1) Which word is most closely associated with meaning of the term gravimetric?
A ) density
B ) mass
C ) mole
D ) volume
2) Which device is best suited to obtaining a specific mass of a chemical species?
A ) balance
B ) beaker
C ) flask
D ) graduated cylinder
Gravimetric Stoichiometry
3) What mass of aluminum oxide can be produced from the complete reaction of 0.482 mol of
oxygen gas? 4Al(s) + 3O(g) = 2Al3O2
A ) 13.8 g
B ) 32.8 g
C ) 49.1 g
D ) 73.7 g
4) Calculate the number of moles of hydrogen gas that should be produced from the complete
reaction of 3.93g of zinc metal. Zn(s) + 2HCl(aq) = H2(g) + ZnCl2(aq)
A ) 0.0601 mol
B ) 3.93 mol
C ) 16.6 mol
D ) 257 mol
Gravimetric Stoichiometry
3) What mass of aluminum oxide can be produced from the complete reaction of 0.482 mol of
oxygen gas? 4Al(s) + 3O(g) = 2Al3O2
A ) 13.8 g
B ) 32.8 g
C ) 49.1 g
D ) 73.7 g
4) Calculate the number of moles of hydrogen gas that should be produced from the complete
reaction of 3.93g of zinc metal. Zn(s) + 2HCl(aq) = H2(g) + ZnCl2(aq)
A ) 0.0601 mol
B ) 3.93 mol
C ) 16.6 mol
D ) 257 mol
Gravimetric Stoichiometry
3) What mass of aluminum oxide can be produced from the complete reaction of 0.482 mol of
oxygen gas? 4Al(s) + 3O(g) = 2Al3O2
A ) 13.8 g
B ) 32.8 g
C ) 49.1 g
D ) 73.7 g
4) Calculate the number of moles of hydrogen gas that should be produced from the complete
reaction of 3.93g of zinc metal. Zn(s) + 2HCl(aq) = H2(g) + ZnCl2(aq)
A ) 0.0601 mol
B ) 3.93 mol
C ) 16.6 mol
D ) 257 mol
Gravimetric Stoichiometry
Use the following information to answer questions # 5-7:
The Chemistry recipe for S’mores is :
2 graham crackers + 4 marshmallows + 3 pieces of chocolate →1 S’more
You have the following supplies in your pantry: 50 graham crackers, 80 marshmallows, 65 pieces of
chocolate.
5. What is limiting reactant?
A. The graham crackers
B. The marshmallows
C. The pieces of chocolate.
D. Chocolate and the graham crackers both limit the amount of S’mores
6. How many S’mores can you make?
A. 25
B. 21
C. 20
D. 67
7. If you borrowed 10 graham crackers, 20 marshmallows, and 4 pieces of chocolate from your
neighbor, and added these to your original amount, how many total S’mores could you make?
A. 30
B. 25
C. 23
D. 78
Gravimetric Stoichiometry
Use the following information to answer questions # 5-7:
The Chemistry recipe for S’mores is :
2 graham crackers + 4 marshmallows + 3 pieces of chocolate →1 S’more
You have the following supplies in your pantry: 50 graham crackers, 80 marshmallows, 65 pieces of
chocolate.
5. What is limiting reactant?
A. The graham crackers
B. The marshmallows
C. The pieces of chocolate.
D. Chocolate and the graham crackers both limit the amount of S’mores
6. How many S’mores can you make?
A. 25
B. 21
C. 20
D. 67
7. If you borrowed 10 graham crackers, 20 marshmallows, and 4 pieces of chocolate from your
neighbor, and added these to your original amount, how many total S’mores could you make?
A. 30
B. 25
C. 23
D. 78
Gravimetric Stoichiometry
Use the following information to answer questions # 5-7:
The Chemistry recipe for S’mores is :
2 graham crackers + 4 marshmallows + 3 pieces of chocolate →1 S’more
You have the following supplies in your pantry: 50 graham crackers, 80 marshmallows, 65 pieces of
chocolate.
5. What is limiting reactant?
A. The graham crackers
B. The marshmallows
C. The pieces of chocolate.
D. Chocolate and the graham crackers both limit the amount of S’mores
6. How many S’mores can you make?
A. 25
B. 21
C. 20
D. 67
7. If you borrowed 10 graham crackers, 20 marshmallows, and 4 pieces of chocolate from your
neighbor, and added these to your original amount, how many total S’mores could you make?
A. 30
B. 25
C. 23
D. 78
Gravimetric Stoichiometry
Use the following information to answer questions # 5-7:
The Chemistry recipe for S’mores is :
2 graham crackers + 4 marshmallows + 3 pieces of chocolate →1 S’more
You have the following supplies in your pantry: 50 graham crackers, 80 marshmallows, 65 pieces of
chocolate.
5. What is limiting reactant?
A. The graham crackers
B. The marshmallows
C. The pieces of chocolate.
D. Chocolate and the graham crackers both limit the amount of S’mores
6. How many S’mores can you make?
A. 25
B. 21
C. 20
D. 67
7. If you borrowed 10 graham crackers, 20 marshmallows, and 4 pieces of chocolate from your
neighbor, and added these to your original amount, how many total S’mores could you make?
A. 30
B. 25
C. 23
D. 78
*questions from http://k-12.pisd.edu/schools/pshs/science/Chem/LR_Study_Guide.pdf
Resources
For those who need extra help with this subject please see these links or
resources.

http://k-12.pisd.edu/schools/pshs/science/Chem/LR_Study_Guide.pdf

http://www.cdli.ca/courses/chem2202/unit01_org02_ilo03/b_activity.html

Chemistry Alberta 20-30 Pages 286 - 293