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For C3H8 + 5O2 giving 3CO2 + 4H2O, how many moles of CO2 form when 0.75 mol of propane burns?
A0.25 mol
B0.75 mol
C3.00 mol
D2.25 mol
Answer & Solution
Correct answer: D. 2.25 mol
1. The equation produces carbon dioxide from propane in a 3 to 1 ratio.
2. The stoichiometric factor is 3 mol CO2 per 1 mol C3H8.
3. Multiply the given amount: 0.75 mol times 3, which is 2.25 mol CO2.
4. Dividing by 3 instead would give 0.25 mol, the reversed-factor error.
5. To get the number of molecules you would then multiply by the number of particles per mole.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 4 "Stoichiometry of Chemical Reactions", section 4.3 Reaction Stoichiometry_
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