Standard Reaction Free Energy Calculator

Standard Reaction Free Energy (ΔG°) is a thermodynamic parameter that measures the energy change for a chemical reaction under standard conditions (typically 25°C, 1 atm pressure, and 1 M concentration for solutions). It indicates whether a reaction is spontaneous (ΔG° < 0) or non-spontaneous (ΔG° > 0) at these conditions, providing insights into the direction and feasibility of the reaction.

Standard Reaction Free Energy Calculator

Here’s a table summarizing key information about Standard Reaction Free Energy (ΔG°):

Term	Definition
ΔG°	Standard Reaction Free Energy, a measure of energy change in a chemical reaction under standard conditions.
Standard Conditions	Typically 25°C, 1 atm pressure, and 1 M concentration for solutions.
Sign of ΔG°	ΔG° < 0 indicates a spontaneous reaction (favoring products).
	ΔG° > 0 indicates a non-spontaneous reaction (favoring reactants).
Equilibrium	ΔG° = 0 at equilibrium; forward and reverse reactions occur at the same rate.
Calculation	ΔG° = -RT ln(K), where R is the gas constant, T is temperature (in Kelvin), and K is the equilibrium constant.
Units	Typically measured in joules per mole (J/mol) or kilojoules per mole (kJ/mol).
Applications	Predicts the spontaneity and direction of chemical reactions.
	Used to determine the feasibility of processes under standard conditions.
Thermodynamic Principle	Related to the first and second laws of thermodynamics.
Basis for Chemical Equilibrium	ΔG° helps determine if a reaction will reach equilibrium and at what position.

This table provides a concise overview of Standard Reaction Free Energy and its significance in thermodynamics and chemical kinetics.

FAQs

How do you calculate the standard reaction free energy?

The standard reaction free energy (ΔG°) can be calculated using the equation:

ΔG° = -RT ln(K)

Where:

• ΔG° is the standard reaction free energy change.
• R is the universal gas constant (8.314 J/(mol·K) or 0.008314 kJ/(mol·K)).
• T is the absolute temperature in Kelvin.
• K is the equilibrium constant of the reaction.

What is the standard free energy of a reaction?

The standard free energy of a reaction (ΔG°) is a measure of the change in Gibbs free energy that occurs when a chemical reaction reaches equilibrium under standard conditions (usually 25°C or 298 K, 1 atmosphere pressure, and 1 molar concentration for solutions). It indicates whether a reaction is spontaneous (ΔG° < 0) or non-spontaneous (ΔG° > 0) under these conditions.

What is the standard Gibbs free energy formula nFE?

The formula nFE is related to the Gibbs free energy change (ΔG) for electrochemical reactions involving the transfer of electrons. It’s given by:

ΔG = -nFE

Where:

• ΔG is the Gibbs free energy change.
• n is the number of moles of electrons transferred in the reaction.
• F is the Faraday constant (approximately 96,485 C/mol or 96,485 J/V·mol).
• E is the cell potential or electromotive force (EMF) of the electrochemical cell.

Is Delta G equal to nFE?

Yes, ΔG = -nFE is a specific form of the Gibbs free energy equation for electrochemical reactions. It relates the change in Gibbs free energy to the number of moles of electrons transferred and the cell potential.

What is the standard free energy of H2O?

The standard free energy change (ΔG°) for the formation of water (H2O) from its elements under standard conditions is approximately -237.2 kJ/mol.

What is the difference between free energy and standard free energy?

Free energy (G) is a thermodynamic potential that represents the maximum reversible work that can be done by a system at constant temperature and pressure. Standard free energy (ΔG°) is the free energy change for a reaction under standard conditions. Standard conditions include a temperature of 25°C (298 K), 1 atmosphere pressure, and 1 molar concentration for solutions.

What is standard free energy measured in?

Standard free energy (ΔG°) is typically measured in joules per mole (J/mol) or kilojoules per mole (kJ/mol).

How to calculate standard Gibbs free energy from the equilibrium constant?

You can calculate ΔG° from the equilibrium constant (K) using the equation mentioned earlier:

ΔG° = -RT ln(K)

Where R is the gas constant (8.314 J/(mol·K)), T is the temperature in Kelvin, and ln denotes the natural logarithm.

How to calculate Gibbs free energy from standard cell potential?

You can calculate the Gibbs free energy change (ΔG) for an electrochemical cell using the formula:

ΔG = -nFE

Where n is the number of moles of electrons transferred, F is the Faraday constant, and E is the cell potential. To calculate ΔG under standard conditions (ΔG°), you would use the standard cell potential (E°) and plug it into the equation.

How do you calculate Gibbs free energy change to determine the direction a reaction will go?

The direction a reaction will go depends on the sign of ΔG:

• If ΔG < 0 (negative), the reaction is spontaneous in the forward direction (products favored).
• If ΔG > 0 (positive), the reaction is non-spontaneous in the forward direction (reactants favored).
• If ΔG = 0, the reaction is at equilibrium.

What is the difference between Delta G and Gibbs free energy?

There is no difference between ΔG and Gibbs free energy (G). ΔG represents the change in Gibbs free energy during a process or reaction.

Is free energy the same as Delta G?

Yes, free energy (G) and ΔG (change in free energy) are the same concepts. ΔG represents the change in Gibbs free energy during a process.

Why is Delta G called free energy?

The term “free energy” in ΔG refers to the energy available to do work in a system. It’s called “free” because it can be used to perform useful work, such as driving chemical reactions or doing mechanical work, under the given conditions.

Can standard free energy be zero?

Yes, the standard free energy change (ΔG°) can be zero, particularly for reactions that are at equilibrium under standard conditions.

What is standard Gibbs free energy at equilibrium?

At equilibrium, the standard Gibbs free energy change (ΔG°) for a reaction is equal to zero. This means that the forward and reverse reactions occur at the same rate, and there is no net change in the concentrations of reactants and products.

What is the Gibbs free energy of CO2?

The Gibbs free energy of carbon dioxide (CO2) depends on the specific conditions and the phase (solid, liquid, or gas) of CO2. Under standard conditions, the ΔG° for the formation of gaseous CO2 from its elements (carbon and oxygen) is approximately -394.36 kJ/mol.

Why free energy is not possible?

Free energy is a concept in thermodynamics that is entirely possible and widely used to describe the energy available for doing work in a system. It’s a fundamental concept in understanding chemical reactions, phase changes, and many other processes in the physical and biological sciences.

Is free energy the same as entropy?

No, free energy (G) and entropy (S) are different thermodynamic properties. Free energy represents the energy available to do work in a system, while entropy is a measure of the disorder or randomness of a system. They are related in the context of Gibbs free energy through the equation:

ΔG = ΔH – TΔS

Where ΔH is the change in enthalpy, T is the temperature, and ΔS is the change in entropy.

Is standard free energy always positive?

No, standard free energy (ΔG°) can be negative, positive, or zero, depending on the nature of the reaction. A negative ΔG° indicates that the reaction is spontaneous under standard conditions, while a positive ΔG° indicates a non-spontaneous reaction. ΔG° can be zero at equilibrium.

What is enthalpy and standard free energy?

Enthalpy (H) is another thermodynamic property that represents the total heat content of a system. Standard free energy (ΔG°) is a measure of the change in Gibbs free energy for a reaction under standard conditions. They are related through the equation:

ΔG° = ΔH° – TΔS°

Where ΔH° is the change in enthalpy under standard conditions, T is the absolute temperature, and ΔS° is the change in entropy under standard conditions.

Why do we calculate free energy?

We calculate free energy to understand and predict the direction and spontaneity of chemical reactions and physical processes. Free energy helps determine whether a process can occur spontaneously and how much work can be extracted from it.

How do you find the standard Gibbs free energy of formation?

The standard Gibbs free energy of formation (ΔG°f) for a compound can be found using tabulated values or calculated using the equation:

ΔG°f = ΔH°f – TΔS°f

Where ΔH°f is the standard enthalpy of formation and ΔS°f is the standard entropy of formation for the compound. The temperature (T) should be in Kelvin.

What is the relationship between standard Gibbs free energy and equilibrium constant?

The relationship between standard Gibbs free energy (ΔG°) and the equilibrium constant (K) is given by the equation:

ΔG° = -RT ln(K)

Where R is the gas constant, T is the temperature in Kelvin, and ln denotes the natural logarithm. This equation relates the spontaneity of a reaction (ΔG°) to its equilibrium constant.

What is the difference between entropy and enthalpy?

Entropy (S) is a measure of the disorder or randomness of a system, while enthalpy (H) is a measure of the total heat content of a system. Entropy is related to the dispersal of energy and the number of possible microscopic configurations, while enthalpy includes both internal energy and pressure-volume work.

What is the formula for Gibbs free energy of a cell?

The formula for the Gibbs free energy change (ΔG) of an electrochemical cell is:

ΔG = -nFE

Where n is the number of moles of electrons transferred, F is the Faraday constant, and E is the cell potential (EMF).

How can we calculate free energy reactions and free energy of formation?

You can calculate the free energy change (ΔG) for a reaction using the equation ΔG = ΔG° + RT ln(Q), where ΔG° is the standard free energy change, R is the gas constant, T is the temperature, and Q is the reaction quotient.

To calculate the standard free energy of formation (ΔG°f) of a compound, you can use tabulated values or calculate it as ΔH°f – TΔS°f, where ΔH°f is the standard enthalpy of formation, and ΔS°f is the standard entropy of formation.

What is Gibbs free energy for a reversible reaction at equilibrium?

For a reversible reaction at equilibrium, the Gibbs free energy change (ΔG) is equal to zero, indicating that there is no net change in the concentrations of reactants and products.

What is the change in Gibbs free energy for a reaction to be spontaneous?

For a reaction to be spontaneous, the change in Gibbs free energy (ΔG) must be negative (ΔG < 0) under the given conditions. This indicates that the reaction can proceed in the forward direction.

What is the difference between reaction Gibbs energy and standard reaction Gibbs energy?

The reaction Gibbs energy (ΔG) represents the actual Gibbs free energy change for a specific reaction under given conditions. Standard reaction Gibbs energy (ΔG°) represents the Gibbs free energy change for the same reaction but under standard conditions (e.g., 25°C, 1 atm pressure, and 1 M concentrations for solutions).

What is the difference between standard and non-standard Gibbs free energy?

Standard Gibbs free energy (ΔG°) is the Gibbs free energy change for a reaction under standard conditions, while non-standard Gibbs free energy (ΔG) is the Gibbs free energy change for the same reaction under non-standard conditions.

What is the relationship between chemical potential and Gibbs free energy?

The chemical potential (μ) is related to the Gibbs free energy (G) through the equation:

μ = G/n

Where μ is the chemical potential, G is the Gibbs free energy, and n is the number of moles of the substance.

What is the relationship between Delta G and Delta G not?

ΔG is the Gibbs free energy change for a reaction under specific conditions, while ΔG° (Delta G not) is the standard Gibbs free energy change for the same reaction under standard conditions. The relationship between them is given by:

ΔG = ΔG° + RT ln(Q)

Where ΔG is the actual Gibbs free energy change, ΔG° is the standard Gibbs free energy change, R is the gas constant, T is the temperature, and Q is the reaction quotient.

Does negative delta G mean more free energy?

No, a negative ΔG means that the system has less free energy than in its initial state. It indicates that the reaction is spontaneous and can release energy.

What is another name for Gibbs free energy?

Another name for Gibbs free energy is Gibbs energy or simply G.

What does it mean if Gibbs free energy is negative?

A negative Gibbs free energy (ΔG < 0) means that a process or reaction is spontaneous under the given conditions. It indicates that the system can release energy and tend to move towards equilibrium.

Does standard free energy ever change?

The standard free energy change (ΔG°) for a specific reaction does not change because it is defined under standard conditions (fixed temperature, pressure, and concentration). However, the actual Gibbs free energy change (ΔG) for the same reaction can change with varying conditions.

At what temperature does delta G become zero?

Delta G (ΔG) becomes zero at a specific temperature called the equilibrium temperature. At this temperature, a reversible reaction reaches equilibrium, and there is no net change in the concentrations of reactants and products, resulting in ΔG = 0.

What is Gibbs free energy for dummies?

Gibbs free energy (G) represents the energy available to do work in a system. It helps determine whether processes or reactions are spontaneous and in which direction they occur. If ΔG is negative, the process is spontaneous, and if ΔG is positive, it is non-spontaneous.

Why delta G is zero at equilibrium?

Delta G (ΔG) is zero at equilibrium because at equilibrium, the forward and reverse reactions occur at the same rate. There is no net change in the concentrations of reactants and products, so the Gibbs free energy change becomes zero.

Is Delta G standard 0 at equilibrium?

Yes, the standard Gibbs free energy change (ΔG°) is zero at equilibrium under standard conditions. This is a defining characteristic of a system at equilibrium.

Why standard Gibbs energy is not zero at equilibrium?

The standard Gibbs free energy change (ΔG°) is not zero at equilibrium because it is defined for reactions under standard conditions, which may differ from the conditions at which a specific system reaches equilibrium. Equilibrium conditions can vary, so ΔG° may not be zero unless those specific conditions match the standard conditions.

What is the Gibbs free energy of propane?

The Gibbs free energy of propane (C3H8) depends on the specific conditions and phase of propane. To calculate it, you would need information on the standard enthalpy of formation (ΔH°f) and the standard entropy of formation (ΔS°f) of propane, along with the temperature.

What was Tesla’s free energy?

Nikola Tesla’s concept of “free energy” referred to his ideas about wireless transmission of electrical energy, as well as the harnessing of energy from natural sources like the Earth’s electromagnetic field. These ideas were not widely accepted in the scientific community and remain controversial.

Is it possible to generate free energy with a flywheel?

A flywheel is a mechanical energy storage device, and while it can store kinetic energy efficiently, it cannot generate “free energy” in the sense of creating energy from nothing. The energy used to spin a flywheel must come from an external source, and there will always be losses due to friction and other factors.

Can energy exist without forces?

No, energy and forces are interconnected concepts in physics. Energy is the ability to do work or apply a force over a distance. Forces are responsible for transferring energy and causing changes in the motion or state of objects. In the absence of forces, energy cannot be transferred or utilized.

What are the 3 laws of thermodynamics?

The three laws of thermodynamics are:

1. The First Law (Law of Energy Conservation): Energy cannot be created or destroyed in an isolated system; it can only change forms. It is also known as the law of conservation of energy.
2. The Second Law (Law of Entropy): In any energy transfer or transformation, the total entropy (measure of disorder or randomness) of an isolated system always increases over time. This law implies the direction of natural processes and the concept of irreversibility.
3. The Third Law (Law of Absolute Zero): As temperature approaches absolute zero (0 K), the entropy of a perfectly crystalline substance approaches zero. It sets a reference point for entropy calculations.

What is free energy in simple words?

Free energy, in simple terms, represents the energy available to do work in a system. It is the energy that can be harnessed to perform useful tasks and drive processes. In thermodynamics, free energy is a measure of a system’s capacity to do work or release energy in a controlled manner.