Answer:
To maintain a pH value of 8.8 in a particular solution the best option is Tris or boric acid.
Explanation:
To decide a good acid/conjugate base pair it is necessary to know the pKa of the acids because every buffer has an optimal effective range due to pH = pKa ± 1. The closer the working pH is to the acid pKa, the buffer will be more effective. Below is the list of the pKa of the different option.
Acetic acid: pKa = 4.76
Boric acid: pKa1 = 9.24 pKa2 = 12.74 pKa3 = 13.80
Ascorbic acid: pKa1 = 4.17 pKa2 = 11.57
Tris: pKa = 8.06
Acetic and Ascorbic acid are too far from the range of 8.8. Thus the best options are boric acid or Tris. To define between these two it is necessary to consider other factors like interaction between components of the solution and the ionic strength required.
B.liquids thanks have a great day
Answer: It is the number in the upper left (atomic number).
Explanation: The atomic number is normally the number of protons. I hope this helps.
Answer:
To calculate the volume we must first find the number of moles
Number of moles (n ) = mass / Molar mass (M)
Since oxygen is diatomic
M of oxygen = 16 × 2 = 32g/mol
n = 16 / 32 = 0.5mol
Next we use the formula
V = n × V(dm³)
where V is the volume
V(dm³) is the volume of 1 mole of a substance at s.t.p which is
22.4dm³
Volume of oxygen gas at s.t.p is
0.5 × 22.4dm³
= 11.20dm³
Hope this helps you
Answer:
The answer is B (25%)
Explanation:
I think the answer is this because it's the smallest value in the options, and if you choose 0% the answer would be wrong.
