Question

consider the following thermochemical equation:
h₂(g) + cl₂(g) → 2 hcl(g) δh = -184.6 kj
what is the enthalpy of reaction (δh) is the reaction is reversed?
-92.3 kj
+92.3 kj
-184.6 kj
+184.6 kj

Explanation:

Step1: Understand the rule of enthalpy sign change

When a reaction is reversed, the sign of the enthalpy change ($\Delta H$) is reversed.

Step2: Apply the rule to the given reaction

Given the original reaction \(H_2(g)+Cl_2(g)\to 2HCl(g)\) with \(\Delta H = - 184.6\space kJ\). When reversed, the new reaction is \(2HCl(g)\to H_2(g)+Cl_2(g)\). So, \(\Delta H\) becomes \(+184.6\space kJ\)

Answer:

+184.6 kJ