In an exothermic reaction, the enthalpy change ΔH is
Answer and explanation
Correct answer: C. negative
- Step 1: Exothermic reactions release heat, so ΔH = E(products) - E(reactants) is negative.
Answer
negative, because the products have less energy than the reactants.
Why not the others: positive, because the products have less energy than the reactants: ΔH is negative when energy is released. positive, because heat is absorbed from the surroundings: that describes an endothermic reaction. zero, because energy is conserved: ΔH is not zero for a reaction that releases heat.\nAnswer: negative.\nWhy not the others: positive: ΔH is positive only when the products have more energy than the reactants, which describes an endothermic reaction. equal to the activation energy: the activation energy is the energy barrier of the reaction, a different quantity from ΔH. zero: ΔH is not zero for a reaction that releases heat to the surroundings.
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