human
What sign is ΔH if the reaction is endothermic, and what sign if it is exothermic?
gpt
It is negative if the reaction is exothermic (energy is released); it is positive if the reaction is endothermic (energy is gained).
Explanation: The sign of ΔH (enthalpy change) indicates whether a reaction is endothermic or exothermic. A negative ΔH indicates an exothermic reaction, where energy is released, while a positive ΔH indicates an endothermic reaction, where energy is gained.