G° vs G
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Re: G° vs G
G° is just G in standard temperature and pressure (298K and 1atm)
Last edited by Chanel Mao 3D on Sun Feb 14, 2021 9:29 pm, edited 1 time in total.
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Re: G° vs G
ΔG = ΔG° + -RTln(Q)
The degrees on the delta G means that this is the standardized value.
The degrees on the delta G means that this is the standardized value.
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Re: G° vs G
G° means under standard conditions (1 atm and 273 K) while G does not specify any conditions.
Re: G° vs G
G° is simply the free energy at standard temperature and pressure, defined as 1 bar (or 1 atm) and 298K.
Re: G° vs G
The difference is implied in the equation. Adding RTln(Q) to the one with the degree sign accounts for the difference. It probably involves temperature and concentrations.
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Re: G° vs G
The formula ΔG = ΔG° + -RTln(Q) lets you calculate ΔG from ΔG° because it accounts for deviations from standard conditions, and I guess you could theoretically go the other way around if you're given ΔG instead of ΔG° to start with.
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Re: G° vs G
G° is just G but at STP (1atm and 298K). G is usually helpful though in the sense that it can be used in lab settings to determine the more "normal" free energy of the reaction.
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Re: G° vs G
Dr. Lavelle's lecture slides stated that when ° is used it is referring to the state in standard conditions, so G is not at standard conditions with 1atm and 298K and G° is.
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Re: G° vs G
G° is G at standard conditions, so 298 K and 1 atm, and G is not at standard conditions.
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Re: G° vs G
G° is just at standard conditions (pressure at 1 atm and temperature at 298K), whereas G can be at any temperature and pressure.
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Re: G° vs G
In addition to this, a UA said you would use the G° equation when the reaction you're working with is at equilibrium and the equation for G when it is not since G is the difference between gibbs free energy of products and reactants at any point.
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Re: G° vs G
the delta G(0) value is just the delta G value but at standard conditions for a certain system. With this, there are different equations that we can use to relate these values. We can relate the delta G(0) value to a system at equilibrium, while we can use the delta G value in the equation, not at equilibrium (delta G = delta G(0) + RTlnQ
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Re: G° vs G
∆Gº is the gibbs free energy under standard conditions 298K and 1atm. ∆G is not under standard conditions and can vary.
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Re: G° vs G
G is not under standard conditions so the question may provide more information in this regard. On the other hand, Gº is under standard conditions (298 K and 1 atm), so we can typically assume these conditions.
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Re: G° vs G
Why is important to differentiate G from G naught? Does it affect enthalpy or entropy differently?
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Re: G° vs G
Susanna Givan 2B wrote:Why is important to differentiate G from G naught? Does it affect enthalpy or entropy differently?
I think it's important because G naught will always be the same for that reaction, since everything is in standard pressure and temperature, but for normal delta G this isn't the case, so we can't just assume each reaction will be the same.
Re: G° vs G
Delta G naught is standard conditions. Delta G is at any point; if equal to delta G naught, it's at equilibrium.
Re: G° vs G
I think of it like K and Q - G knott will be under standard conditions while G will be at adjusted conditions.
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