12.2. Stoichiometric Calculations http://www.ck12.org
and temperature need to be held constant over the course of the reaction for these conversion factors to remain true,
the reaction does not need to be run at STP; Avogadro’s hypothesis is true regardless of the pressure and temperature
being used.
Sample Problem 12.6: Volume-Volume Stoichiometry
The combustion of propane gas produces carbon dioxide and water vapor (Figure12.5).
C 3 H 8 (g) + 5O 2 (g)→3CO 2 (g) + 4H 2 O(g)FIGURE 12.4
Silver oxide is used in button batteries
such as these watch batteries.What volume of oxygen is required to completely combust 0.650 L of propane? What volume of carbon dioxide is
produced in the reaction?
Step 1: List the known quantities and plan the problem.
Known
- given: 0.650 L C 3 H 8
- 1 volume C 3 H 8 = 5 volumes O 2
- 1 volume C 3 H 8 = 3 volumes CO 2
Unknown
- volume O 2 =? L
- volume CO 2 =? L
Step 2: Solve.
0 .650 L C 3 H 8 × 15 L CL O 3 H^28 = 3 .25 L O 2
0 .650 L C 3 H 8 × 13 L CL CO^2
3 H 8
= 1 .95 L CO 2
Step 3: Think about your result.