Answer to Question #18445 in Physical Chemistry for Diana

Question

In respiration, glucose is oxidized by oxygen gas to produce carbon dioxide gas, water, and energy. What is the energy released when 18.0 g of glucose is consumed?

Answer 1

Find H from the balanced reaction C₆H₁₂O₆(s) + 6O₂ —> 6CO₂ + 6H₂O
∆H° = ΣnH° - ΣnH°
∆H° = 6( -393.5 kJ) + 6( -285.8 kJ) +1273.1 kJ = [ -2361 kJ + (-1714.8 kJ) ] - [ -1273.1 kJ ] = -2802.8 kJ (this is the enthalpy of the balanced reaction ∆H)
To find molar enthalpy:
∆H° = -2802.7 kJ/mol
n = 18g / 180g/mol = 0.1 mol
∆H° = -2802.7 kJ/mol * 0.1 mol = -280.27 kJ