Question

Which reaction is endothermic?

H2(g) + ½ O2(g) → H2O(g), ΔH = -57.82 kcal
½N2(g) + O2(g) + 8.1 kcal → NO2(g)
½N2(g) + 3/2H2(g) → NH3(g) + 11.0 kcal
C(diamond) + O2(g) → CO2, ΔH = -94.50 kcal

Answer 1

the second equation is endothermic. the energy is listed in the reactants side. if it was a product it is exothermic. also the H value is negative exothermic positive endothermic

Answer 2

The endothermic reaction is:

`(1)/(2)N_2(g) + O_2(g) + 8.1 kcal \rightarrow NO_2(g)`

Step-by-step explanation:

Endothermic reaction is a type of of chemical reaction in which energy is absorbed from the surrounding. The temperature of the surrounding decreases. Energy absorbed is used during the chemical reaction.

So from the given reactions the endothermic reaction is;

`(1)/(2)N_2(g) + O_2(g) + 8.1 kcal \rightarrow NO_2(g)`

In this reaction 8.1 kcal of enrgy is used by the reactants to give product.

Where as chemical reaction in which energy is released during the reaction is termed as exothermic reaction.