Handout 10 Assignment
1. What volume of oxygen at STP is needed to completely burn 15.0 g of methanol
(CH3OH) in a fondue burner? (CO2 + H2O are products) [15.7 L O2 ]
2CH3OH + 3O2  2CO2 + 4H2O
Volume O2= 15.0 g x 1 mol x 3 mol = 0.702028081 mols
32.05 g 2 mol
PV=nRT  V=nRT/P
V= (0.702028081 mols)(8.314)(273 K)
101.325 kPa
V=15.7 L of O2
2. When sodium chloride is heated to 800°C it can be electrolytically decomposed into Na
metal & chlorine (Cl2) gas. What volume of chlorine gas is produced (at 800°C and 100
kPa) if 105 g of Na is also produced?[204 LCl2 ]
2NaCl  2Na + Cl2
Volume Cl2= 105 g x 1 mol x 1 mol= 2.283601566 mols
22.99 g 2 mols
PV=nRT  V=nRT/PV= (2.283601566 mols)(8.314)(1073 K)
100 kPa
V= 204 L Cl2
3. What mass of propane (C3H8) can be burned using 100 L of air at SATP? Note: 1) air
is 20% O2, so 100 L of air holds 20 L O2, 2) CO2 and H2O are the products of this
reaction. [7.1 g C3H8 ]
C3H8 + 5O2  3CO2 + 4H2O
PV=nRT  n=PV/RT
n=(100 kPa)(20 L)
(8.314)(298 K)
n=0.807241928 mols O2 x 1 mol x (44.11 g) = 7.1 g C3H8
5 mol
1 mol
4. A 5.0 L tank holds 13 atm of propane (C3H8) at 10°C. What volume of O2 at 10°C &
103 kPa will be required to react with all of the propane? [320 L O2 ]
C3H8 + 5O2 3CO2 + 4H2O
PV=nRT  n=PV/RT
n=(1317.225)(5.0 L)
(8.314)(283)
n=2.79919197318 mols x 5 mols =13.99598659 mols of O2
1 mols
PV=nRT  V=nRT/P
V= (13.99598659 mols)(8.314)(283K)
103 kPa
V=320 L O2
5. Nitroglycerin explodes according to:
4 C3H5(NO3)3(l)  12 CO2(g) + 6 N2(g) + 10 H2O(g) + O2(g)
a)
Calculate the volume, at STP, of each product formed by the reaction of 100 g
of C3H5(NO3)3.
[29.6 L CO2; 14.8 L N2; 24.7 L H2O, 2.47 L O2 ]
4C3H5(NO3)3  12CO2 + 6N2 + 10 H2O + O2
a) 100 g x 1 mol x 12 mol = (1.320945797 mols)(8.314)(273 K) = 29.6 L CO2
227.11 g 4 mol
101.325 kPa
100 g x 1 mol x 6 mol = (0.660472898 mols)(8.314)(273 K) = 14.8 L N2
227.11 g 4 mol
101.325 kPa
100 g x 1 mol x 10 mol = (1.100788164 mols)(8.314)(273 K) = 24.7 L H2O
227.11 g 4 mol
101.325 kPa
100 g x 1 mol x 1 mol = (0.110078816 mols)(8.314)(273 K) = 2.47 L O2
227.11 g 4 mol
101.325 kPa
b)
200 g of C3H5(NO3)3 is ignited (and completely decomposes) in an otherwise
empty 50 L gas cylinder. What will the pressure in the cylinder be if the
temperature stabilizes at 220°C? [523 kPa]
b) 2.64 mols CO2
1.32 mols N2
2.20 mols H2O
0.220 mols O2
Total mols= 6.38 mols
PV=nRT  P=nRT/V
P= (6.38 mols)(8.314)(493 K)
50 L
P= 523 kPa