Chemistry - Thermochemistry Question with Solution | TestHub
In biological cells that have a plentiful supply of O2, glucose is oxidized completely to CO2 and H2O by a process called aerobic oxidation. Muscle cells may be deprived of O2 during vigorous exercise and, in that case, one molecule of glucose is converted to two molecules of lactic acid, CH3CH(OH)COOH, by a process called anaerobic glycolysis.
C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(l); ΔH° = -2880 kJ/mol
C6H12O6(s) → 2CH3CH(OH)COOH(s); ΔH° = +2530 kJ/mol
Which of the following statements is true regarding aerobic oxidation and anaerobic glycolysis with respect to energy change as heat?
Options:
Answer:
Solution:
The advantage of aerobic oxidation can be calculated as the difference in enthalpy change between glycolysis and aerobic respiration.
Δ Hadvantage = Δ Hglycolysis - Δ Haerobic
Given the values:
Δ Hglycolysis = +2530 kJ/mol
Δ Haerobic = -2880 kJ/mol
Substituting these values into the equation:
Δ Hadvantage = +2530 - (-2880) = 2530 + 2880 = 5410 kJ/mol
Therefore, aerobic oxidation provides an advantage of 5410 kJ/mol of extra energy released per mole of glucose. This corresponds to option (a).
