Want this question answered?
The purpose is to determine the available energy. Some of the energy in any system is useless - can't be converted into useful work.
because, AMERICA!I'm a free man!
it is conventional to define gravitational potential energy (GPE) of object A to be 0 when the object is free from the gravitational field of object B (i.e. at a infinite distance away) As the objects get closer together, the GPE decreases, thus is less than 0. Therefore the GPE of any object normally has a negative value (however it all just depends on where you define to be the point at which the object has 0 GPE)
change in free energy is positive
Because they want to and it's a free country.
when H is negative and S is positive
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.
Spontaneous reaction
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.
Yes, as long as the entropy of the universe increases.
If the sign of ΔH is _______ and the sign of ΔS is _______ , then the magnitude of TΔS must be ________ than the magnitude of ΔH for the reaction to be spontaneous. The Gibbs free energy equation is ΔG = ΔH - TΔS. negative; negative; less
150
-225.3 KJ
δg = (-992.0) - (298)(-294.6)(1/1000)
One may go to the local library to research Gibbs Free Energy theory. One may also look towards Wikipedia, Ebooks, Boundless or Chemistry About to find information about the Gibbs Free Energy theory.
Chemical reactions that have high activation energy, with multiple intermediates and transitions states that have higher activation energy than the initial requirement, but which still have a negative Gibbs free energy change.
Gibbs free energy -- symbol G. If the change in Gibbs free energy for a reaction is negative, the reaction is spontaneous. If it is zero, you are at equilibrium. If it is positive, the reaction is NOT spontaneous.G ≡ H -TS (or in another useful form dG = dH -TdS)whereH is enthalpyT is absolute temperatureS is entropy