Question

Consider respiration, one of the most common chemical reactions on earth.

C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + energy

What mass of carbon dioxide forms in the reaction of 25.00 grams of glucose with 40.00 grams of oxygen? How much of the excess reactant will be left after the limiting reactant is completely used up? (C = 12.01 amu, H = 1.01 amu, O = 16.00 amu)

Mass of carbon dioxide = ___grams CO₂

Mass of excess reactant remaining = ___grams of excess reactant left unreacted

Answer 1

Balanced equation:
C₆H₁₂O₆ + 6 O₂ ====> 6 CO₂ + 6 H₂O
25.00 grams of glucose = 25 /180.15 = 0.1387 Moles

40.00 grams of oxygen = 40 /32 = 1.25 Moles

One equivalent of glucose needs 6 equivalent of oxygen

Limiting reagent is glucoes

0.1387 Moles of glucose needs 0.8326 Moles of oxygen to produce 0.8326 Moles of CO2

0.8326 Moles of oxygen = 0.8326 x 32 = 26.64 gm of O2

Excess reagent =40 -26.64 = 13.36 gm

0.8326 Moles of CO2 = 0.8326 x 44 = 36.64 gm of CO2

Mass of carbon dioxide = 36.64 grams CO2

Mass of excess reactant remaining = 13.36 grams of excess reactant left unreacted