Answer:

Explanation:
Hello,
In this case, since the pH defines the concentration of hydrogen:
![pH=-log([H^+])](https://tex.z-dn.net/?f=pH%3D-log%28%5BH%5E%2B%5D%29)
![[H^+]=10^{-pH}=10^{-3.4}=3.98x10^{-4}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D10%5E%7B-pH%7D%3D10%5E%7B-3.4%7D%3D3.98x10%5E%7B-4%7D)
And the percent ionization is:
![\% \ ionization=\frac{[H^+]}{[HA]}*100\%](https://tex.z-dn.net/?f=%5C%25%20%5C%20ionization%3D%5Cfrac%7B%5BH%5E%2B%5D%7D%7B%5BHA%5D%7D%2A100%5C%25)
We compute the concentration of the acid, HA:
![[HA]=\frac{[H^+]}{\% \ ionization}*100\%=\frac{3.98x10^{-4}}{66\%} *100\%\\\\](https://tex.z-dn.net/?f=%5BHA%5D%3D%5Cfrac%7B%5BH%5E%2B%5D%7D%7B%5C%25%20%5C%20ionization%7D%2A100%5C%25%3D%5Cfrac%7B3.98x10%5E%7B-4%7D%7D%7B66%5C%25%7D%20%20%2A100%5C%25%5C%5C%5C%5C)
![[HA]=6.03x10^{-4}](https://tex.z-dn.net/?f=%5BHA%5D%3D6.03x10%5E%7B-4%7D)
Thus, the Ka is:
![Ka=\frac{[H^+][A^-]}{[HA]}=\frac{3.98x10^{-4}*3.98x10^{-4}}{6.03x10^{-4}}\\ \\Ka=2.63x10^{-4}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7B%5BH%5E%2B%5D%5BA%5E-%5D%7D%7B%5BHA%5D%7D%3D%5Cfrac%7B3.98x10%5E%7B-4%7D%2A3.98x10%5E%7B-4%7D%7D%7B6.03x10%5E%7B-4%7D%7D%5C%5C%20%20%5C%5CKa%3D2.63x10%5E%7B-4%7D)
So the pKa is:

Regards.
The answer is definitely D
Answer:
D
Explanation:
Because the number of protons is the same as the atomic number, we know what the number of protons has to be 26. The mass number, 55, is the same as the number of protons plus neutrons. Lastly, because there is no charge on this atom, the number of electrons would have to be the same as the number of protons, which is 26.
It is called a watt and or wattage
Blood.
<span>Blood is heterogeneous because it has corpuscles (blood cells and platelets) physically suspended in blood plasma. Blood plasma and the corpuscles have different properties and can be separated by methods such as centrifugation. Also, blood is considered a colloid suspension because it has the properties of both a colloid and a suspension. This is because the blood plasma acts as a colloid. More so, if blood was left to settle,then the blood cells would collect at the bottom hence taking the characteristic of a suspension. </span>
<span>Salad dressing.</span>
<span>Depending on the type of salad, it can either be a heterogeneous or homogeneous mixture. If the salad dressing is only of vinegar or any other oil, then it is a homogenous mixture. However, if it involves a mixture of vinegar and other oils, pepper, herbs, and etcetera, then it is a heterogeneous mixture</span>