Answer:
There are no acceptable descriptions at all on that list of choices.
Answer:
pKa of the histidine = 9.67
Explanation:
The relation between standard Gibbs energy and equilibrium constant is shown below as:
![\Delta{G^0} =-RT \ln \frac{[His]}{[His+]}](https://tex.z-dn.net/?f=%5CDelta%7BG%5E0%7D%20%3D-RT%20%5Cln%20%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D)
R is Gas constant having value = 0.008314 kJ / K mol
Given temperature, T = 293 K
Given, 
So, Applying in the equation as:-
![15\ kJ/mol=-0.008314\ kJ/Kmol\times 293\ K\times \ln \frac{[His]}{[His+]}](https://tex.z-dn.net/?f=15%5C%20kJ%2Fmol%3D-0.008314%5C%20kJ%2FKmol%5Ctimes%20293%5C%20K%5Ctimes%20%5Cln%20%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D)
Thus,
![\frac{[His]}{[His+]}=e^{\frac{15}{-0.008314\times 293}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D%3De%5E%7B%5Cfrac%7B15%7D%7B-0.008314%5Ctimes%20293%7D)
![\frac{[His]}{[His+]}=0.00211](https://tex.z-dn.net/?f=%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D%3D0.00211)
Also, considering:-
![pH=pKa+log\frac{[His]}{[His+]}](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D)
Given that:- pH = 7.0
So, 
<u>pKa of the histidine = 9.67</u>
3I₂ + 2Al → 2AlI₃
m(I₂)=3M(I₂)m(Al)/{2M(Al)}
m(I₂)=3*253.8*20.4/{2*27.0}=287.64 g
Answer:
The answer to your question is the letter D. a decomposition reaction
Explanation:
This is a brief description of the main chemical reactions.
a) A synthesis reaction is when two reactants are combined to form only one product.
b) A disynthesis reaction. I have not heard about this chemical reaction, I think it does not exist.
c) A combustion reaction is when an organic molecule reacts with oxygen to form carbon dioxide and water.
d) A decomposition reaction is when one reactant splits to form two or more products.
Gneiss is a sedimentary rock and granite is a metamorphic rock.
<h3>What are rocks?</h3>
Rocks are geological hard materials that are made up of various types which include:
- Sedimentary rocks: These are rocks that made up of various layers formed from sediments. Example is the gnesis.
- Metamorphic rocks: These are rocks that are form from pre existing rocks that undergoes some transformation. Example is granite
Therefore, Gneiss is a sedimentary rock and granite is a metamorphic rock.
Learn more about rocks here:
brainly.com/question/398139
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