To be able to calculate the number of moles for this problem, for simplicity, we assume that it is an ideal gas. We use the equation PV = nRT. We do as follows:
PV = nRT
n = PV / RT
n = 1(100000) / 0.08206 (27 + 273.15)
n = 4060.04 mol
The percent of histidine side chains would be deprotonated at pH 7.5 is 5.77 %.
<h3>What is pKa?</h3>
The term pKa refers to the negative logarithm of the acid dissociation constant (Ka). The pH is the negative logarithm of the hydrogen ion concentration.
Hence;
Ka = Antilog (-6) =
[H^+] = Antilog (-7.5) = 
We now have to use the formula;
α = ![\sqrt{} \frac{Ka}{[H^+] }](https://tex.z-dn.net/?f=%5Csqrt%7B%7D%20%5Cfrac%7BKa%7D%7B%5BH%5E%2B%5D%20%7D)
α = 
α = 5.77 %
Hence, the percent of histidine side chains would be deprotonated at pH 7.5 is 5.77 %.
Learn more about percent dissociation: brainly.com/question/12273293
Well, depending on the charge, it could be Cu; if it has a charge of 2+