The structure of this oligopeptide is attached:
It consists of arginine - alanine - phenylalanine and leucine
From the picture we can see that N terminus charge is +1
Also Arginine is considered as basic amino acid with charge +1
C terminus charge is -1
At pH = 8, the whose pKa are less than pH will be deprotonated and the net charge will be +1
So the net charge of this oligopeptide is +1 at pH = 8
In order of relative atomic mass.
To answer this item, we assume that oxygen behaves ideally such that it is able to fulfill the following equation,
PV = nRT
If we are to retain constant the variable n and V.
The percent yield can therefore be solved through the following calculation,
n = (10.5 L)/(22.4 L) x 100%
Simplifying,
n = 46.875%
Answer: 48.87%