G = -nFE
Therefore, G will be negative when EMF is positive.
A positive sum of the two half-reactions' standard potentials
Guys watch out the question, if your question end with positive then the answer will be An endothermic reaction that decreases in entropy. If the question end with negative then its An exothermic reaction that increases in entropy--APEX hope this help
When H is positive and S is negative
The unit of Gibbs free energy, which is joules (J), is used to measure the amount of energy available to do work in a chemical reaction. The spontaneity of a chemical reaction is determined by the sign of the Gibbs free energy change (G). If G is negative, the reaction is spontaneous and can occur without external intervention. If G is positive, the reaction is non-spontaneous and requires external energy input to proceed.
Gibbs free energy and standard free energy are both measures of the energy available to do work in a chemical reaction. The main difference is that Gibbs free energy takes into account the temperature and pressure of the system, while standard free energy is measured under specific standard conditions. In chemical reactions, the change in Gibbs free energy determines whether a reaction is spontaneous or non-spontaneous. If the Gibbs free energy change is negative, the reaction is spontaneous, while a positive change indicates a non-spontaneous reaction. The relationship between Gibbs free energy and standard free energy lies in the fact that the standard free energy change can be used to calculate the Gibbs free energy change under any conditions.
An endergonic reaction is a reaction in which the change in Gibbs free energy is positive, indicating that the reaction requires an input of energy to proceed. This means that the products of the reaction have more free energy than the reactants.
A positive sum of the two half-reactions' standard potentials
The driving force of a reaction is the change in free energy. This change determines whether a reaction will proceed spontaneously or require external energy input. A negative change in free energy indicates a spontaneous reaction, while a positive change requires energy input.
Guys watch out the question, if your question end with positive then the answer will be An endothermic reaction that decreases in entropy. If the question end with negative then its An exothermic reaction that increases in entropy--APEX hope this help
When H is positive and S is negative
The name of the single thermodynamic quantity is Gibbs free energy (G). The symbol for Gibbs free energy is ΔG (delta G). The sign of ΔG determines whether a reaction is spontaneous (negative ΔG) or non-spontaneous (positive ΔG).
The unit of Gibbs free energy, which is joules (J), is used to measure the amount of energy available to do work in a chemical reaction. The spontaneity of a chemical reaction is determined by the sign of the Gibbs free energy change (G). If G is negative, the reaction is spontaneous and can occur without external intervention. If G is positive, the reaction is non-spontaneous and requires external energy input to proceed.
In an endergonic reaction, the total energy of the products is higher than the total energy of the reactants. Energy input from the surroundings is needed for the reaction to occur, often in the form of ATP or another high-energy molecule. These reactions are non-spontaneous and require an input of energy to proceed.
Gibbs free energy and standard free energy are both measures of the energy available to do work in a chemical reaction. The main difference is that Gibbs free energy takes into account the temperature and pressure of the system, while standard free energy is measured under specific standard conditions. In chemical reactions, the change in Gibbs free energy determines whether a reaction is spontaneous or non-spontaneous. If the Gibbs free energy change is negative, the reaction is spontaneous, while a positive change indicates a non-spontaneous reaction. The relationship between Gibbs free energy and standard free energy lies in the fact that the standard free energy change can be used to calculate the Gibbs free energy change under any conditions.
Since the question seems to be about reactions - and the whole idea of a reaction is that something is changing... The CHANGE in Gibbs free energy will always be positive for a spontaneous reaction. As far as whether the Gibbs free energy of a system (without the term "change" attached) ... Since Gibbs free energy is a state function, it is always defined relative to a standard state. Asking if the Gibbs free energy is positive is akin to asking how "high" something is - the answer depends on where you define zero to be. If you define 0 height to be the level of the ground you are standing on, you will get a different answer than if you define zero height to be "sea level". A cactus in Death Valley may have a positive height relative to the ground, but would actually have a negative height relative to sea level. Likewise, the Gibbs free energy of a system will be positive or negative (or zero) depending on what you define as the standard state.
Gibbs free energy (G) will always be negative for spontaneous processes at constant temperature and pressure, indicating that the reaction can occur without external input. Conversely, Gibbs free energy will be positive for non-spontaneous processes, suggesting that the reaction requires energy input to proceed. When G is zero, the system is at equilibrium, meaning there is no net change in the concentrations of reactants and products.
An endergonic reaction is a chemical reaction in which the standard change in free energy is positive, and energy is absorbed. To view the source and read more about endergonic reactions go to: http://en.wikipedia.org/wiki/Endergonic_reaction