Consider the reaction 2 H 2 + O 2 ⟶ 2 H 2 O Δ H rxn = − 484 kJ Which answer best describes the transfer of heat that occurs when 1.60 mol H 2 reacts? 387 kJ absorbed 484 kJ released 387 kJ released 774 kJ absorbed 484 kJ absorbed 774 kJ released

387 kJ energy is released

Explanation:

Endothermic reactions: These are the reactions in which energy is required in the reaction. The energy of the products are more than the energy of the reactants. is positive.

Exothermic reactions: These are the reactions in which energy is released in the reaction. The energy of the products is less than the energy of the reactants. is negative.

The given balanced equation is ;

According to stoichioetry :

2 moles of hydrogen reacts to give = 484 kJ of heat

Thus 1.60 moles of hydrogen reacts to give =

Thus 387 kJ energy is released

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.