## spontaneity

$\Delta S = \frac{q_{rev}}{T}$

annikaying
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### spontaneity

What is most important in deciding if a reaction is spontaneous (ex enthalpy, entropy, Gibbs free energy)?

jisulee1C
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### Re: spontaneity

Gibbs Free Energy. If delta G is negative you know that the forward reaction is spontaneous.

Miriam Villarreal 1J
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### Re: spontaneity

Gibbs free energy change determines if a reaction is spontaneous under the conditions of constant pressure and constant temperature

Eunice Nguyen 4I
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### Re: spontaneity

Gibbs Free Energy (delta G) gives information about the spontaneity of a reaction. If deltaG<0, then the reaction is spontaneous.

504939134
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### Re: spontaneity

If delta G (Gibbs free energy) is negative then you know that it was spontaneous.

Anna Heckler 2C
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### Re: spontaneity

Gibbs free energy will allow you to determine if the reaction is spontaneous or not (based on the sign). Also enthalpy can be used, as negative enthalpy means the reaction is exothermic since it is releasing heat.

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### Re: spontaneity

Definitely Gibbs Free energy (delta G)! If delta G is negative then the reaction is spontaneous, but if it’s positive it is not.

Posts: 103
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### Re: spontaneity

Gibbs Free Energy is definitely the best indicator of spontaneity as it takes into account entropy and enthalpy.

Mandeep Garcha 2H
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### Re: spontaneity

Gibbs free energy is one of the easiest ways to determine whether a reaction is spontaneous or not. A negative delta G is spontaneous (exergonic) and a positive delta G is not spontaneous (endergonic).

Esha Chawla 2E
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### Re: spontaneity

annikaying wrote:What is most important in deciding if a reaction is spontaneous (ex enthalpy, entropy, Gibbs free energy)?

Personally, I think that Gibbs free energy is the best indicator because it combines enthalpy and entropy. Moreover, it's extremely clear cut: if delta G is negative, it is spontaneous; if delta G is positive, it is not spontaneous. However, this does not mean that you can't estimate if a reaction is spontaneous or not using enthalpy or entropy. It's just that Gibbs free energy is much more clear cut.

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### Re: spontaneity

A negative delta G means that the reaction is spontaneous.

Kaitlyn Ang 1J
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### Re: spontaneity

As everyone above said, Gibbs free energy is how you determine if a reaction is spontaneous or not. However, it might be important to remember that the reason Gibbs free energy is so clear cut is that it’s because it’s based off total entropy which is always increasing.

san_2F
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### Re: spontaneity

Delta G is the greatest determiner of whether a reaction will be spontaneous or not. If delta G is negative, then the reaction is spontaneous. You could also use the equation DeltaG= DeltaH- T*DeltaS, given either DeltaH or DeltaS, to see what values need to be in order to produce a spontaneous reaction.

Isabella Dal Porto 1H
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### Re: spontaneity

Aside from delta G, a reaction is spontaneous if delta H is negative and delta S is positive.

805329408
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### Re: spontaneity

jisulee1C wrote:Gibbs Free Energy. If delta G is negative you know that the forward reaction is spontaneous.

Why is it Gibbs Free Energy vs, using enthalpy or entropy.

pmokh14B
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### Re: spontaneity

Gibbs free energy, which is determined by enthalpy and entropy.

Anish Natarajan 4G
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### Re: spontaneity

If a reaction has an increase in entropy or a decrease in enthalpy, then it is more likely to be spontaneous. To compute the actual value you need to check if the Gibbs free energy of a reaction is negative and to do that you use the equation delta G=deltaH-T*deltaS

Natalie Benitez 1E
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### Re: spontaneity

Why exactly does delta G have to be negative to be considered spontaneous?

SarahCoufal_1k
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### Re: spontaneity

Gibbs free energy has to be negative. B/c delta G= Delta H - T*DeltaS the others contribute to delta G

SarahCoufal_1k
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### Re: spontaneity

Natalie Benitez 1E wrote:Why exactly does delta G have to be negative to be considered spontaneous?

If delta G is negative that means it is going from higher energy(reactants) to lower energy (products). If it is going from high to low, you need very little (if any input of energy) so it will happen spontaneously.
On the other hand when Delta G is positive, it is going from lower energy of reactants to higher energy of products. Because it is going from low to high, it needs an input of energy. The reaction will not take place unless there is this input which. is why it is not spontaneous

Vinita Saxena 2I
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### Re: spontaneity

Gibbs free energy is usually a delta, so final minus initial. When delta G is negative the products have less gibbs free energy, making the reation spontaneous

Daria MacAuslan 1H
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### Re: spontaneity

If delta g, gibbs free energy, is a negative value, then the reaction in question can be determined to be spontaneous

Rafsan Rana 1A
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### Re: spontaneity

To add on, when Gibbs free energy is negative that means that according the equation for gibbs free energy, delta S or change in entropy is positive and if change in entropy is positive, it means that a process is spontaneous.

Juana Abana 1G
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### Re: spontaneity

If the delta g value is negative then the reaction is considered spontaneous.

Anokhi Patel 2B
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### Re: spontaneity

when delta g is negative, the reaction is spontaneous and vice versa with positivity.

SimranSangha4I
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### Re: spontaneity

Gibbs free energy! If the delta g is negative then it is going to be spontaneous.

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### Re: spontaneity

gibbs free energy!!

Rida Ismail 2E
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### Re: spontaneity

delta G is the most forward way to determine if the reaction is spontaneous or not.

san_2F
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### Re: spontaneity

Gibbs free energy is the best and most accurate way to tell whether a reaction is spontaneous, but using the equation delta G= delta H- T*delta S, it is possible to see what values of delta H and delta S gives a a negative delta G value.

SarahCoufal_1k
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### Re: spontaneity

Gibbs free energy is the best determinant. I think it's best since it includes both entropy and enthalpy in its formula. If it's negative it is spontaneous

Celine 1F
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### Re: spontaneity

Gibbs free energy can help determine spontaneity.

105311039
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### Re: spontaneity

Gibbs free energy under conditions of constant temperature and pressure! your delta G must be negative because that is the energy free to do work!

Leslie Almaraz 4G
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### Re: spontaneity

the spontaneity does depend on the enthalpy and entropy as seen in the equation

William Chan 1D
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### Re: spontaneity

Gibbs free energy is defined by a combination of enthalpy, temperature, and entropy. If Gibbs free energy is negative, that means the reaction is spontaneous, and if it is positive, the reaction will not be spontaneous. Note, spontaneity does NOT mean that the reaction will just proceed quickly, just that it is thermodynamically favorable. The largest factor is definitely enthalpy. Entropy can play a small role, but enthalpy usually dominates the spontaneity of a reaction.

Bryan Chen 1H
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### Re: spontaneity

gibbs free energy!!!!