Calculate The Delta G Using The Following Information 4hno3

What is delta G?

The Gibbs free energy change (delta G) is a thermodynamic property that measures the energy available to do work in a chemical reaction. It combines enthalpy (delta H) and entropy (delta S) according to the equation:

Where:

• ΔG = Gibbs free energy change (kJ/mol)
• ΔH = Enthalpy change (kJ/mol)
• T = Absolute temperature (K)
• ΔS = Entropy change (J/mol·K)

A negative delta G indicates a spontaneous reaction, while a positive delta G means the reaction is non-spontaneous under standard conditions.

How to calculate delta G

To calculate delta G for reactions involving 4HNO3, you need:

1. The standard free energy change (ΔG°) for the reaction
2. The temperature at which the reaction occurs
3. The change in entropy (ΔS) for the reaction

The standard free energy change (ΔG°) can be calculated using the standard enthalpy change (ΔH°) and standard entropy change (ΔS°):

For non-standard conditions, you can use the equation:

Where Q is the reaction quotient.

Standard conditions

Standard conditions for Gibbs free energy calculations are:

• Temperature: 298 K (25°C)
• Pressure: 1 atm (101.325 kPa)
• Concentration: 1 M for solutes

Standard free energy values (ΔG°) are typically reported under these conditions.

Example calculation

Let's calculate delta G for the reaction:

Given:

• ΔH° = -1200 kJ/mol
• ΔS° = -50 J/mol·K
• Temperature = 298 K

First, calculate ΔG°:

For non-standard conditions with Q = 0.5:

This negative value indicates the reaction is spontaneous under these conditions.

Interpretation of results

The delta G value tells you:

• If ΔG < 0: Reaction is spontaneous
• If ΔG = 0: Reaction is at equilibrium
• If ΔG > 0: Reaction is non-spontaneous

For reactions involving 4HNO3, a negative delta G typically indicates the formation of stable aluminum nitrate and hydrogen gas is favorable.