Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols for use in experiments.
The value of ΔG° at this temperature is -18034.18 J/mol
Calculation,
Given information
formation constant (Kf)= 1.7 × 
Universal gas constant (R) = 8.314 J/K• mol
Temperature = 25° C = 25 °C + 273 = 300 K
Formula used:
ΔG° = -RT㏑Kf
By putting the valur of R,T, Kf we get the value of ΔG°
ΔG° = - 8.314 J/K• mol×300K㏑ 1.7 × 
ΔG° = -2494.2㏑ 1.7 ×
= -18034.18 J/mol
So, change in standard Gibbs's free energy is -18034.18 J/mol
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Answer:
4.0 moles
Explanation:
The following data were obtained from the question:
Volume (V) = 12L
Pressure = 5.6 atm
Temperature (T) = 205K
Gas constant (R) = 0.08206 atm.L/Kmol
Number of mole (n) =?
Using the ideal gas equation: PV = nRT, the number of mole of the gas can be obtained as follow
PV = nRT
5.6 x 12 = n x 0.08206 x 205
Divide both side by 0.08206 x 205
n = (5.6 x 12)/(0.08206 x 205)
n = 4.0 moles
Therefore, the number of mole of the gas is 4.0 moles
This problem is providing the basic dissociation constant of ibuprofen (IB) as 5.20, its pH as 8.20 and is requiring the equilibrium concentration of the aforementioned drug by giving the chemical equation at equilibrium it takes place. The obtained result turned out to be D) 4.0 × 10−7 M, according to the following work:
First of all, we set up an equilibrium expression for the given chemical equation at equilibrium, in which water is omitted for it is liquid and just aqueous species are allowed to be included:
![Kb=\frac{[IBH^+][OH^-]}{[IB]}](https://tex.z-dn.net/?f=Kb%3D%5Cfrac%7B%5BIBH%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BIB%5D%7D)
Next, we calculate the concentration of hydroxide ions and the Kb due to the fact that both the pH and pKb were given:

![[OH^-]=10^{-5.8}=1.585x10^{-6}M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D10%5E%7B-5.8%7D%3D1.585x10%5E%7B-6%7DM)

Then, since the concentration of these ions equal that of the conjugated acid of the ibuprofen (IBH⁺), we can plug in these and the Kb to obtain:
![6.31x10^{-6}=\frac{(1.585x10^{-6})(1.585x10^{-6})}{[IB]}](https://tex.z-dn.net/?f=6.31x10%5E%7B-6%7D%3D%5Cfrac%7B%281.585x10%5E%7B-6%7D%29%281.585x10%5E%7B-6%7D%29%7D%7B%5BIB%5D%7D)
Finally, we solve for the equilibrium concentration of ibuprofen:
![[IB]=\frac{(1.585x10^{-6})(1.585x10^{-6})}{6.31x10^{-6}}=4.0x10^{-7}](https://tex.z-dn.net/?f=%5BIB%5D%3D%5Cfrac%7B%281.585x10%5E%7B-6%7D%29%281.585x10%5E%7B-6%7D%29%7D%7B6.31x10%5E%7B-6%7D%7D%3D4.0x10%5E%7B-7%7D)
Learn more:
(Weak base equilibrium calculation) brainly.com/question/9426156