Question

When ΔH is positive, the reaction is exothermic, and when ΔH is negative, the reaction is endothermic. For an exothermic reaction process, the temperature of the surrounding will increase and the temperature of the system will decrease.

a) True
b) False

Answer 1

The statement is false because an exothermic reaction has a negative ΔH, meaning it releases heat, and an endothermic reaction has a positive ΔH, meaning it absorbs heat from the surroundings. The correct answer is b.

Step-by-step explanation:

The statement 'When ΔH is positive, the reaction is exothermic, and when ΔH is negative, the reaction is endothermic' is incorrect. The correct statement is: when ΔH is negative, the reaction is exothermic, and when ΔH is positive, the reaction is endothermic. For an exothermic reaction, the temperature of the surroundings will indeed increase, as heat is released by the system into the surroundings. Conversely, for an endothermic reaction, the temperature of the surroundings will decrease, as the system absorbs heat from the surroundings.

In an exothermic process, the enthalpy (H) of the system decreases (ΔHrxn is negative), meaning the reaction releases heat and is energetically downhill. Meanwhile, an endothermic process results in an increase in the enthalpy (ΔHrxn is positive) of the system, indicating the reaction absorbs heat and is energetically uphill. Hence the correct answer is b.