A hand‑warmer contains 0.30 g of a mixture that reacts with air to produce heat. The reaction can be represented as: C₆H₁₂O₆(s) + 6 O₂(g) → 6 CO₂(g) + 6 H₂O(l). Using the following average bond energies (kJ mol⁻¹): C–C 347, C–H 413, O–H 463, C=O 799, O=O 498, C–O 358, O–H (in water) 463, C–O (in CO₂) 799, calculate the total energy released (in kJ) when 0.30 g of glucose reacts completely. (Assume the hand‑warmer contains pure glucose.)

The reaction releases about 1.8 × 10² kJ of energy. Breaking the bonds in glucose and oxygen requires 1.3 × 10² kJ, while forming the bonds in CO₂ and water releases 3.1 × 10² kJ, giving a net release of 1.8 × 10² kJ.

The correct option is exothermic reaction: correct Unit 4.5 answer for Energy transfer during exothermic and endothermic reactions. It directly supports the approved learning objective to describe everyday uses of exothermic reactions, including self-heating cans and hand warmers. This keeps the answer anchored to Energy transfer during exothermic and endothermic reactions within Exothermic and endothermic reactions, and avoids mixing energy transfer, reaction profiles, activation energy, chemical cells, fuel cells, exothermic reactions and endothermic reactions unless the objective names them.