Chapter 10, Problem 48QAP

Interpretation Introduction

Interpretation:

The enthalpy change for the following reaction should be determined.

$\text{2C}\left(\text{s}\right)+{\text{H}}_2\left(\text{g}\right)\to {\text{C}}_2{\text{H}}_2\left(\text{g}\right)$

Concept Introduction:

Enthalpy of a reaction is a state function thus; change in enthalpy of a reaction does not depend on the path of the reaction.

The change in enthalpy is same if the same reaction takes place in one step or series of steps. This is known as Hess’s law. There are following characteristics of change in enthalpy which are important to calculate the change in enthalpy of a reaction using Hess’s law.

1. For a reversed reaction, the sign of enthalpy changes of the reaction also reversed.
2. If any reactant or product is multiplied by any integer in the chemical reaction, enthalpy change of that reactant or product is also multiplied by the same integer.