MCAT Chemistry Question — Chemical Reactions
- Feb 12, 2017
- MCAT Question of the Day
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
If a reaction vessel initially contains 360 grams of C6H12O6 (MW = 180 g/mole), and if the reaction produces 440 grams of CO2, what is the limiting reagent?
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360 g C6H12O6 x (1 mol C6H12O6 / 180 g C6H12O6) x (6 mol CO2 / 1 mol C6H12O6) x (44 g CO2 / 1 mol CO2) = 528 g CO2
Since only 440 grams of carbon dioxide are actually produced, not all of the glucose combusts. Thus, the oxygen must be the limiting reagent in this problem, making answer choice B correct. Choices C and D can be eliminated because products are never limiting reagents. Since there will be leftover C6H12O6, it is not the limiting reagent, eliminating answer choice A.
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