Question

which quantity will always have a negative value? (1 point)

the change in energy in a system during an exothermic reaction
the total bond energy of the reactants in an endothermic reaction
the change in energy in a system during an endothermic reaction
the total bond energy of the products during an exothermic reaction

Explanation:

• For exothermic reactions, the system releases energy to the surroundings, so the change in system energy ($\Delta E$) is negative.
• Endothermic reactions absorb energy, so system energy change is positive.
• Bond energies of reactants/products are positive values (energy required to break bonds), and in exothermic reactions, product bond energy is higher than reactants, but still positive; in endothermic reactions, reactant bond energy is higher, also positive.

Answer:

the change in energy in a system during an exothermic reaction