Question

explain your answer, how do I know if it rises or falls?

Hypothetical elements A2 and B2 react according to the following equation, forming the compound AB. Az(aq) + B2(aq) 2AB(aq); AH = +271 kJ/mol If solutions Az(aq) and B2(aq), starting at the same temperature, are mixed in a coffee-cup calorimeter, the reaction that occurs is a exothermic, and the temperature of the resulting solution rises. b endothermic, and the temperature of the resulting solution rises. c endothermic, and the temperature of the resulting solution falls. d exothermic, and the temperature of the resulting solution falls. e exothermic or endothermic, depending on the original and final temperatures.

Answer 1

Delta H is positive.
This means heat is absorbed by the reaction.
So, solution must be providing this heat. So, temperature of solution will decrease.

Delta H is positive which means reaction is endothermic.

Answer: c