Given the following thermochemical equation detailing the combustion of glucose C₆H₁₂O₆(s) 6O₂(g) CO₂(g) 6H₂O(g) $\Delta$H_rxn= -2803 kJ/mol C_6-H₁₂O₆ Determine the amount of glucose needed to release 30 kJ of energy.

Question

Quizplus · Accepted Answer

First, calculate the amount of energy released per mole of glucose:
ΔH = -2803 kJ/mol

Then, use stoichiometry to convert from moles of glucose to energy released:
1 mole glucose -> -2803 kJ
x moles glucose -> -30 kJ

x = (1 mol glucose * -30 kJ) / -2803 kJ/mol
x = 0.3219 mol glucose

Finally, convert from moles of glucose to grams using the molar mass:
0.3219 mol glucose * 180.16 g/mol = 58.0 g glucose

Therefore, the amount of glucose needed to release 30 kJ of energy is approximately 1.93 g (choice B).

Given the Following Thermochemical Equation Detailing the Combustion of Glucose Δ\DeltaΔ

Given the Following Thermochemical Equation Detailing the Combustion of Glucose $\Delta$