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
Data:
F (force) = 22.0 N
m (mass) = ? (in Kg)
a (acceleration) = 5.5 m/s²
We apply the data to the Resultant Force formula, we have:
4.0 kg
I hope this helps. =)
The scale used to measure the basicity of a substance is called the pH Scale. A base which when measured on a pH scale obtains a value greater than 7 but less than or equal to 10 is weak base and from 10-14 is strong base
<h3>Meaning of Base and basicity</h3>
A base is any substance that has the ability to accept hydrogen ion in water and also netralize an acid when mixed together.
Basicity is an attribute associated with the pH scale measurement of values above 7 to 14.
Basicity increases on the scale from 7 to 14. On the pH scale 7 is neutral. So the higher we go the more basic a solution becomes until it gets to its highest point which is 14.
In conclusion, The scale used to measure the basicity of a substance is called the pH Scale. A base which when measured on a pH scale obtains a value greater than 7 but less than or equal to 10 is weak base and from 10-14 is strong base
Learn more about basicity : brainly.com/question/172153
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Answer:
2.8 mol/min is the rate of appearance of 
at that moment.
Explanation:
Rate of the reaction = R
![R=\frac{-1}{2}\frac{d[N_2O_5]}{dt}=\frac{1}{4}\frac{d[NO_2]}{dt}=\frac{1}{1}\frac{d[O_2]}{dt}](https://tex.z-dn.net/?f=R%3D%5Cfrac%7B-1%7D%7B2%7D%5Cfrac%7Bd%5BN_2O_5%5D%7D%7Bdt%7D%3D%5Cfrac%7B1%7D%7B4%7D%5Cfrac%7Bd%5BNO_2%5D%7D%7Bdt%7D%3D%5Cfrac%7B1%7D%7B1%7D%5Cfrac%7Bd%5BO_2%5D%7D%7Bdt%7D)
Rate of disappearance of 
is ![=-\frac{d[N_2O_5]}{dt}= 1.40 mol/min](https://tex.z-dn.net/?f=%3D-%5Cfrac%7Bd%5BN_2O_5%5D%7D%7Bdt%7D%3D%201.40%20mol%2Fmin)
![R=\frac{-1}{2}\frac{d[NO_2]}{dt}](https://tex.z-dn.net/?f=R%3D%5Cfrac%7B-1%7D%7B2%7D%5Cfrac%7Bd%5BNO_2%5D%7D%7Bdt%7D)
Rate of appearance of is ![=\frac{1}{4}\frac{d[NO_2]}{dt}:](https://tex.z-dn.net/?f=%3D%5Cfrac%7B1%7D%7B4%7D%5Cfrac%7Bd%5BNO_2%5D%7D%7Bdt%7D%3A)
![R=\frac{1}{4}\frac{d[NO_2]}{dt}](https://tex.z-dn.net/?f=R%3D%5Cfrac%7B1%7D%7B4%7D%5Cfrac%7Bd%5BNO_2%5D%7D%7Bdt%7D)
![\frac{d[NO_2]}{dt}=4\times 0.70 mol/min=2.8 mol/min](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BNO_2%5D%7D%7Bdt%7D%3D4%5Ctimes%200.70%20mol%2Fmin%3D2.8%20mol%2Fmin)
2.8 mol/min is the rate of appearance of at that moment.
