Question

For the following example, identify the following. 2N2O(g) → 2N2(g) + O2(g) _____ . It is not possible to determine without more information. (A) a positive ΔH and a negative ΔS(B) a negative ΔH and a negative ΔS (C) a negative ΔH and a positive ΔS (D) a positive ΔH and a positive ΔS

Answer 1

Answer:  (D) a positive ΔH and a positive ΔS

Explanation:

Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.

Decomposition reactions are those in which one reactant converts to two or more products by absorption of energy and thus is a endothermic reaction.

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

In the given reaction:  

$2N_2O(g)\rightarrow 2N_2(g)+O_2(g)$

The energy is absorbed by the reactants and thus it is endothermic and $\Delta H=+ve$ and the number of moles of gaseous substances are increasing as we proceed towards products and thus the entropy increases, and $\Delta S=+ve$.