Stoichiometry Test Review
Concept of Mole/Molar Ratio
1) 1.56 X 1021 atoms Na X 1 mol Na
= 0.00259 mol Na
6.02 X 1023
2) 1.58 mol O2 X 4 mol Al = 2.1 mol Al
3 mol O2
3) 2.16 mol Al2O3 X
4 mol Al
= 4.32 mol Al
2 mol Al2O3
4) a) 2 mol Al
3 mol S
3 mol S
b)
2 mol Al
3 mol S
1 mol Al2(SO4)3
1 mol Al2(SO4)3
3 mol S
c) 0.900 mol S X 2 mol Al = 0.600 mol Al
3 mol S
d) 1.16 mol Al2(SO4)3 X
3 mol S
= 3.48 mol S
1 mol Al2(SO4)3
5) 2 NH3  3 H2 + N2
0.145 mol NH3 X 3 mol H2 = 0.218 mol H2
2 mol NH3
0.145 mol NH3 X 1 mol N2 = 0.0725 mol N2
2 mol NH3
6) 0.260 mol C6H12O6 X 6.02 X 1023 molecules C6H12O6 X
1 mol C6H12O6
7) a) 22.99 amu (read from periodic table)
b) 32.07 amu
c) 35.45 amu
8) a) 1.35 mol Fe X 55.85 g Fe = 75.4 g Fe
1 mol
b) 24.5 mol O X 16.00 g O = 392 g O
1 mol O
24 atoms
1 mol C6H12O6
=
3.76 X 1024 atoms
c) 0.876 mol Ca X 40.08 g Ca = 35.1 g Ca
1 mol Ca
d) 1.25 mol Ca3(PO4)2 X 270.1 g Ca3(PO4)2 = 337.6 g Ca3(PO4)2
1 mol Ca3(PO4)2
e) 0.625 mol Fe(NO3)2 X 241.88 g Fe(NO3)3 = 151.2 g Fe(NO3)3
1 mol Fe(NO3)3
f) 0.600 mol C4H10 X 58.14 g C4H10 = 34.9 g C4H10
1 mol C4H10
g) 1.45 mol (NH4)2CO3 X 96.11 g (NH4)2CO3 = 139.4 g (NH4)2CO3
1 mol (NH4)2CO3
9) a) 21.5 g CaCO3 X 1 mol CaCO3 = 0.19 mol CaCO3
111 g CaCO3
b) 1.56 g NH3 X 1 mol NH3 = 0.918 mol NH3
17 mol NH3
c) 16.8 g Sr(NO3)2 X 1 mol Sr(NO3)2 = 0.0792 mol Sr(NO3)2
212 g Sr(NO3)2
d) 6.98 g Na2CrO4 X 1 g Na2CrO4 X 1 mol Na2CrO4 = 4.3 X 10-8 mol Na2CrO4
106 g
162 g Na2CrO4
18) a) 0.12 mol Cl2 X 1 mol Na2S2O3 = 0.03 mol Na2S2O3
4 mol Cl2
b) 0.12 mol Cl2 X 8 mol HCl = 0.24 mol HCl
4 mol Cl2
c) 0.12 mol Cl2 X 5 mol H2O = 0.15 mol H2O
4 mol Cl2
d) 0.24 mol HCl X 5 mol H2O = 0.15 mol H2O
8 mol HCl
19) a) 4 P + 5 O2 P4O10
b) 6.85 g P X 1 mol P X 5 mol O2 X 32 g O2
31 g P
4 mol P
1 mol P4O10
= 8.85 g O2
c) 8 g O2 X 1 mol O2 X 1 mol P4O10 X 283.88 g P4O10 = 14.2 g P4O10
32 g O2
5 mol O2
1 mol P4O10
d) 7.46 g P4O10 X 1 mol P4O10 X
284 g P4O10
4 mol P
X 31 g P
1 mol P4O10
= 3.25 g P
1 mol P
20) 11.45 g Cu X 1 mol Cu X 8 mol HNO3 X 63 g HNO3 = 11.4 g HNO3
63.55 g Cu
3 mol Cu
1 mol HNO3
21) a) 4.20 mol Al X 1 mol Fe2O3 = 2.1 mol Fe2O3
2 mol Al
1.75 mol Fe2O3 X
2 mol Al
= 3.5 mol Al
1 mol Fe2O3
4.20 mol Al – 3.5 mol Al = 0.7 mol Al
1.75 mol Fe2O3 – 2.1 mol Fe2O3 = -0.35 mol Fe2O3
Fe2O3 is the limiting reactant.
b) 1.75 mol Fe2O3 X
2 mol Fe
1 mol Fe2O3
X 55.85 g Fe = 195.5 g Fe
1 mol Fe
22) 3 AgNO3 + FeCl3  Fe(NO3)3 + 3 AgCl
32.4 g FeCl3 X 1 mol FeCl3 = 0.200 mol FeCl3 X 3 mol AgNO3 = 0.600 mol AgNO3
162.2 g FeCl3
1 mol FeCl3
18.0 g X 1 mol AgNO3 = 0.106 mol AgNO3 X 1 mol FeCl3 = 0.035 mol FeCl3
170 g AgNO3
3 mol AgNO3
0.200 mol FeCl3 – 0.035 mol FeCl3 = 0.165 mol FeCl3
0.106 mol AgNO3 – 0.600 mol AgNO3 = -0.494 mol AgNO3
0.165 mol FeCl3 X 162.2 g FeCl3 = 26.8 g FeCl3
1 mol FeCl3
23) 75.00 g Ba(NO3)2 X 1 mol Ba(NO3)2 X 1 mol BaSO4 X 233 g BaSO4 = 84.8 g BaSO4
261 g Ba(NO3)2 1 mol Ba(NO3)2 1 mol BaSO4
63.45 g X 100% = 74.8 %
84.8 g
24) 25.0 g X 1 mol AlCl3 = 0.187 mol AlCl3 X 3 mol H2SO4 = 0.281 mol H2SO4
133.35 g AlCl3
2 mol AlCl3
30.0 g H2SO4 X 1 mol H2SO4 = 0.306 mol H2SO4 X 2 mol AlCl3 = 0.204 mol AlCl3
98 g H2SO4
3 mol H2SO4
0.187 mol AlCl3 – 0.204 mol AlCl3 = -0.017 mol AlCl3
0.306 mol H2SO4 – 0.281 mol H2SO4 = 0.025 mol H2SO4
0.187 mol AlCl3 X 1 mol Al2(SO4)3 X 342 g Al2(SO4)3 = 32.0 g Al2(SO4)3
2 mol AlCl3
28.46 g X 100 = 88.9%
32.0 g
1 mol Al2(SO4)3