Calculate The Standard Free Energy Change for The Following 3mg

Introduction

The standard free energy change (ΔG°) is a fundamental concept in chemical thermodynamics that quantifies the energy available to do work in a system at standard conditions. It is calculated using the standard Gibbs free energy of formation (ΔG°f) of the products and reactants.

Understanding ΔG° helps chemists predict whether a reaction will occur spontaneously. A negative ΔG° indicates a spontaneous reaction, while a positive ΔG° suggests a non-spontaneous reaction.

Formula

The standard free energy change for a reaction is calculated using the following formula:

Where:

• ΔG° is the standard free energy change
• ΔG°f(products) is the sum of the standard Gibbs free energies of formation of the products
• ΔG°f(reactants) is the sum of the standard Gibbs free energies of formation of the reactants

Calculation

To calculate the standard free energy change, you need the standard Gibbs free energies of formation for all the products and reactants involved in the reaction. These values can be found in thermodynamic tables or databases.

For example, consider the reaction:

The standard Gibbs free energies of formation for the reactants and products are:

Using the formula:

This indicates that the reaction is spontaneous under standard conditions.

Interpretation

The standard free energy change provides valuable insights into the spontaneity of a reaction. A negative ΔG° means the reaction will proceed spontaneously to form products, while a positive ΔG° suggests that energy must be supplied for the reaction to occur.

For the example reaction:

The calculated ΔG° of -474.2 kJ indicates that the reaction will occur spontaneously, releasing energy in the process.