Chemistry Reference
In-Depth Information
2H
2
O + CO
2
methane + oxygen
water + carbon dioxide
x dm
3
CH
4
+ 2O
2
40 dm
3
methane
oxygen
coefficients
1
x
2
40 dm
3
=
# of moles
Cross-multiplying, we get 2x = 40 dm
3
, so the volume of methane is
20 dm
3
.
Before you move on to the practice problems, let me remind you one
more time that this shortcut may only be used for the volume-volume prob-
lems. The reason for this should be clear. All gases have a molar volume of
22.4 dm
3
/mole at STP; however, substances don't all have the same mass at
any temperature or pressure.
Now, on to the practice problems.
Lesson 7-6 Review
Answer questions 1-3 based on the following balanced chemical equa-
tion. Assume all volumes are at STP.
C
3
H
8
+ 5O
2
4H
2
O + 3CO
2
propane + oxygen
water + carbon dioxide
1.
How many dm
3
of oxygen are required to completely react with 5.0
dm
3
of propane?
2.
How many dm
3
of carbon dioxide will be produced if 15 dm
3
of
oxygen react with an excess of propane?
3.
How many dm
3
of water vapor will be produced with 90.0 dm
3
of
carbon dioxide?
Complete all of the required steps to answer the following questions.
Assume STP for all volumes of gases.
4.
How many dm
3
of hydrogen will react with 4.0 dm
3
of nitrogen in the
synthesis reaction that produces ammonia?
5.
How many dm
3
of oxygen are required to react with an excess of
glucose in order to produce 5.0 dm
3
of carbon dioxide through the
process of respiration?
