CHEMISTRY 11 – STOICHIOMETRY WORKSHEET
1) Consider the unbalanced reaction:
2
7
46
____ C2H6 + ____ O2 → ____ CO2 + ____ H2O
(a) How many oxygen molecules react with 6 molecules of C2H6?
Omdecdes
6 molecules CaH6×
=
02
Qmoleculescatlb
molecules
21
=
molecules
7
(b) How many H2O molecules are produced when 12 molecules of C2H6 react?
Haomoleales
=
12
-
36
molecules
Caltex
6 molecules Hoo
Qmoleculescatlb
molecules
(c) How many moles of oxygen are needed to produce 18 mol of CO2?
7 mol 02
02=18 mol Coax
MOI
4mo1C02
32
=
mol
2) Nitromethane, a fuel occasionally used in some drag racers, burns according to the reaction
4 CH3NO2 (l) + 3 O2 (g) → 4 CO2 (g) + 6 H2O (l) + 2 N2 (g)
(a) What mass of H2O is produced when 0.150 g of CH3NO2 is burned?
6molH2O
gHzO= 0.150g ×lmdCH3N02
×4mdCH3N02
61.0g
×
18 .0g
lmoltbo
0.0664g
=
(b) What volume of O2 (g) at STP is required to produce 0.250 g of CO2?
xjmgmol
02=0.2509
xlmdcsk
L
44.0
02
×
22.4L
lmol 02
02
0.955L
=
(c) What mass of H2O is produced when 0.410 g of CO2 is produced?
gH2O= 0.410g
=
0.252g
6molH20
×4mdCO2
×lmdC02
44.0g
×
18 .0g
lmoltbo
3) Pentane, C5H12, burns according to the reaction:
C5H12 (l) + 8 O2 (g) → 5 CO2 (g) + 6 H2O (l)
(a) What mass of CO2 (g) is produced when 100.0 g of C5H12 (l) is burned?
(b) What mass of O2 (g) is required to produce 60.0 g of H2O (l)?
(c) What mass of C5H12 (l) is required to produce 90.0 L of CO2 (g) at STP?
(d) What volume of O2 (g) at STP is required to produce 70.0 g of CO2 (g)?
(e) What volume of O2 (g) at STP is required to produce 48.0 L of CO2 (g) at STP?
(f) What mass of H2O (l) is made when the burning of C5H12 gives 106 L of CO2 (g) at STP?
4) An organic compound, C14H10O3S (s), undergoes combustion.
(a) Write a balanced equation for this reaction.
+1602
1402+5420+502
CHHIOO }S
(b) What mass of H2O is produced when 0.150 g of C14H10O3S is burned?
×lmdG4Hw3S×
MOICHHIOOD
SMOIHZO
gH2O=
IMOIHZO
0.150g
=
18.0g
×
258.1g
1
0.0523g
(c) What volume of gas will be produced when 0.316 g of C14H10O3S is burned and the products
collected at STP?
includes both C02&SO2
IMOICHHNOB
IMDCHHIOOI
Hmolgas
IMOIGAS
Lgas
=
0.3169
×
zsgtg
22.4L
×
×
×27mol02
2mdPbO
02=100
|mo1O2
=
0.411L
(d) What volume of O2 (g) at STP is required to produce 0.250 g of CO2?
xlbmollk
HMOICOZ
xlmyyl
.Og×lmdPb0
L02
=
=
0.250g
×
.gg02
22.4L
lmol 02
0.145L
(e) What mass of H2O is produced when 0.410 g of CO2 is produced?
IMOIHZO
Smoltz
14mdC02
×lmdC02
gH2O=
0.410g
×
×
18.09
44.0g
=
0.0599g
5) Tetraethyl lead, Pb(C2H5)4, is an “antiknock” ingredient which was added to some gasolines.
Tetraethyl lead burns according to the equation:
2 Pb(C2H5)4 (l) + 27 O2 (g) → 2 PbO (s) + 16 CO2 (g) + 20 H2O (l)
(a) What volume of O2 (g) at STP is consumed when 100.0 g of PbO are formed?
L
=
135L223.2g
×
22.4L
(b) How many molecules of CO2 are formed when 1.00 x 10-6 g of tetraethyl lead is burned?
mdPbk2tH4×16molC02
2mdPbK2Hs)4
lmolcck
02=1.00×105×1
molecules
×
6.02×1023
molecules
323.2g
=
1.49×1016molecules
(c) How many molecules of H2O are formed when 135 molecules of O2 react?
molecules
molecules 420
02=100
H2O=135
molecules
02×20
27 molecules
molecules
(d) What volume of O2 (g) at STP, in milliliters, is required to react with 1.00 x 1015 molecules of
tetraethyl lead?
2mdPb¢2Hs)4
×lmdPbK2tH4
×27mol02
02=1.00
's
L
molecules
6.02×1023molecules
-
=
5.02×10
4
ml
×
22.4L
lmol 02
104
xlml