GCHEM STOICHIOMETRY I LAB CONCEPT PROBLEMS
In chemical reaction (2 H2 + 1 O2 2 H20) the stoichiometric coefficients (2 and 1) represent the moles
of H2 & O2 that will react to produce (2 ) moles of H2O.
2 moles of H2 will react with exactly 1 moles of O2
2 moles H2
1 moles O2
2 moles of H2 will react to yield exactly 2 moles of H2O
2 moles H2
2 moles
H2O
0.17 grams H2 react with excess O2 to produce how many grams of H2O ?
0.17 grams H2
1 moles H2
2 moles H2O
18.02 grams H2O = 1.5 grams H2O
2.016 grams H2
2 moles H2
1 moles H2O
MOLES TO MOLES: 2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g)
1) How many moles of H2 gas will be produced when 5.2 moles of Al completely reacts with HCl ?
5.2 moles Al
2)
3 moles H2 = 7.8000 moles H2 S/F = 2
2 moles Al
7.8 moles H2
How many moles of AlCl3 will be produced when 10.0 milli-moles of Al is comsumed ?
1 x 10 33 mole Al
1 milli-mole Al
10.0 milli-moles Al
1 moles AlCl3 = 10.0 x 10 3
1 mole Al
1.00 x 10 2 mole AlCl3
S/F = 3
MOLES TO GRAMS: Balance equation ___Zn(s) + _2__AgNO3(aq) _2__Ag(s) + ___Zn(NO3)2(aq)
3) How many grams of Ag will be produced when 10.5 moles of Zn completely reacts ? (ans: 2.27 X 103 g Ag )
10.5
moles Zn
2 moles Ag
1 mole Zn
107.9 grams Ag = 2,265.90 grams Ag S/F = 3
1 mole Ag
2,270 grams Ag
4) How many grams of AgNO3 will be required to produce 12.2 milli-moles of Zn(NO3)2 ?
12.2 milli-moles Zn(NO3)2
1 x 10-3 moles Zn(NO3)2
1 milli-mole Zn(NO3)2
2 moles AgNO
169.88 grs AgNO3 = 4.145 S/F = 3 4.14 grs AgNO3
1 mole Zn(NO3)2 1 mole AgNO3
5) How many grams of Ag will be produced when 2.2 x 10- 4 kilo-moles Zn completely reacts ?
2.2 x 10-4 kilo-moles Zn
1 x 103 moles Zn
1 kilo-mole Zn
2 moles Ag
1 mole ZSn
107.87 grams Ag = 47.46
1 mole Ag
S/F = 2
47 grams Ag
GRAMS TO MOLES: Balance equation _2_ZnS(s) + _3_O2(g) _2_ZnO(s) + _2__SO2(g)
6) How many moles ZnO will be produced when 15.0 grs of ZnS reacts ?
15.0 grams ZnS
1 mole ZnS
2 moles ZnO = 0.1539 moles ZnS = 0.1544
97.46 grs ZnS 2 moles ZnS
(ans: .154 moles ZnO)
S/F = 3
0.154 moles ZnO
7) How many moles of O2 gas will be needed to produce 2.0 x 102 milli-grams SO2 gas ?
2.0 x 10 2 milli-grs SO2 1 x 10 -3 grs SO2 1 moles SO2 3 moles O2
1 milli-gr SO2
64.07 grs SO2 2 moles SO2
= 4.7 10 x -3
S/F = 2
4.7 x 10-3 mloes O2
8) How many moles of SO2 gas will be produced when 120.5 kilo-grams of ZnS reacts completely ?
120.5 kilo-grs ZnS
1 x 10-3 grs ZnS moles ZnS
2 mole SO2 = 1.236 x 10-3 S/F = 3
1 kilo-gr ZnS
97.46 grs ZnS 2 moles ZnS
1.24 x 10-3 moles SO2
GRAMS TO GRAMS: See balanced equation Fe3O4(s) + 4CO(g) 3Fe (s) + 4CO2(g)
1) How many grams of solid Fe will be produced when 100.0 grams of Fe3O4 completely reacts ?
100.0 grs Fe3O4
moles Fe3O4
231.52 grs Fe3O4
3 moles Fe
55.84 grs Fe = 72.356 grs Fe
1 mole Fe3O4 1 mole Fe
S/F = 4
72.36 grs Fe
2) How many kilo-grams of Fe will be produced when 1000.0 pounds (454.5 grams/pound) of CO gas
reacts completely ?
1000.0 pounds CO 454.4 grs CO
1 pound CO
1 moles CO 3 moles Fe
28.01 grs CO 4 moles CO
55.85 grs Fe = 217.90 S/F = 4
1 mole Fe
217.9 grs Fe
3) How many grams of Fe3O4 will be needed to produce 1.54 x104 centi-grams of Fe ?
1.54 x 104 centi-grs Fe 1 x 10 -2 grs Fe 1 moles Fe
1 mole Fe3O4 231.52 grs Fe3O4 S/F = 3
centi grs Fe 55.85 grs Fe 3 moles Fe
1 mole Fe3O4
213 grs Fe3O4
4) You completely react 45.1 grams of Fe3O4 and 75.1 grams of CO gas. How many grams of Fe can be
produced by the Fe3O4 reaction ? by the CO2 reaction ?
5) You produced 200.0 grams of solid Fe. How many kilo-grams of CO2 was produced ?
200.0 grs Fe
1 mole Fe
55.85 grs Fe
4 moles CO2 44.01 grs CO2
3 moles Fe moles CO2
kilo-grams CO2 = 0.21013
1 x 103 grs CO2
S/F = 4
0.2101 kilo-grs CO2
6) Methanol (CH3OH) and O2 (g) react to form CO2(g) and H2O(l). If 342.4 milli-grams of methanol
react completely, how many grams of water will be produced ? Balance equation ?
2 CH3OH(l) + 3 O2(g) 2 CO2 + 4 H2O (l)
342.4 milli-grs CH3OH 1 x 10-3 grs CH3OH moles CH3OH
milli-grs CH3OH 32.04 grs CH3OH
2 moles CO2
44.01 grs CO2 = .47031 S/F = 4 .4703 grs CO2
2 moles CH3OH mole CO2
7) Vanadium (V) oxide reacts with hydrogen gas as follows: V2O5(s) + 2H2(g) V2O3(s) + 2H2O(l). If
4.93 grams of hydrogen reacts completely, how many grams of Vanadium (III) oxide are produced ?
8) Dichlorine pentoxide and water react as follows: Cl2O5 + H2O 2 HClO3. If you desire to
produce 81.7 grams of HClO3, how many grams of dichlorine pentoxide ? and water are needed ?
jpechunf06/2004