Question

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

Answer 1

Answer: 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.$\Delta H$ 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.$\Delta H$ is negative.

The given balanced equation is ;

$2H_2+O_2\rightarrow 2H_2O$  $\Delta H=-484kJ$

According to stoichioetry :

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

Thus 1.60 moles of hydrogen reacts to give =$\frac{484}{2}\times 1.60=387kJ$

Thus 387 kJ energy is released