One of the best buffer choice for pH = 8.0 is Tris with Ka value of 6.3 x 10^-9.
To support this answer, we first calculate for the pKa value as the negative logarithm of the Ka value:
pKa = -log Ka
For Tris, which is an abbreviation for 2-Amino-2-hydroxymethyl-propane-1,3 -diol and has a Ka value of 6.3 x 10^-9, the pKa is
pKa = -log Ka
= -log (6.3x10^-9)
= 8.2
We know that buffers work best when pH is equal to pKa:
pKa = 8.2 = pH
Therefore Tris would be a best buffer at pH = 8.0.
I'm not sure about 2 but in 3 it would float
Kindly checkout the attached pic. It contains all your required questions.
Answer:
<h2>Density = 0.46 g/mL</h2>
Explanation:
Density of a substance can be found by using the formula
<h3>

</h3>
From the question
mass = 5.52 g
volume = 12 mL
Substitute the values into the above formula and solve for the Density
That's
<h3>

</h3>
We have the final answer as
<h3>Density = 0.46 g/mL</h3>
Hope this helps you