Calculate the energy change when 2 moles of water are formed from the reaction of hydrogen and oxygen, given that the bond energies are 432 kJ/mol for O-H bonds and 498 kJ/mol for H-H bonds. Assume the reaction involves breaking 2 H-H bonds and forming 4 O-H bonds.

-264 kJ.

The correct option is endothermic reaction: correct Unit 4.5 answer for Energy transfer during exothermic and endothermic reactions. It directly supports the approved learning objective to explain that the temperature of the surroundings decreases during an endothermic reaction. 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.