Answer:
Total partial pressure, Pt = 821 mm Hg
Partial pressure of Helium, P1 = 105 mm Hg
Partial pressure of Nitrogen, P2 = 312 mm Hg
Partial pressure of Oxygen, P3 = ? mm Hg
According to Dalton's law of Partial pressures,
Pt = P1 + P2 + P3
So, <u>P3 = 404 mm Hg</u>
When we can get Pka for K2HPO4 =6.86 so we can determine the Ka :
when Pka = - ㏒ Ka
6.86 = -㏒ Ka
∴Ka = 1.38 x 10^-7
by using ICE table:
H2PO4- → H+ + HPO4
initial 0.4 m 0 0
change -X +X +X
Equ (0.4-X) X X
when Ka = [H+][HPO4] / [H2PO4-]
by substitution:
1.38 X 10^-7 = X^2 / (0.4-X) by solving for X
∴X = 2.3x 10^-4
∴[H+] = X = 2.3 x 10^-4
∴PH = -㏒[H+]
= -㏒ (2.3 x 10^-4)
∴PH = 3.6
Mass number is equal to the number of protons plus the number of neutrons in a nucleus of an atom
The answer is 33.2 moles of a solute is present in 4.00 L of an 8.30 M solution , Option A is correct .
<h3>
What is Molarity ?</h3>
Molarity is defined as the amount of solute (in moles)in per litre of solution.
It is also known as molar concentration of a solution , It is expressed in mol/l
We can rearrange this equation to get the number of moles:
n= M * V
The molarity of solution is 8.3 M and the volume given is 4 litres
the moles will be n = 8.30 * 4 = 33.2 moles
Therefore 33.2 moles of a solute is present in 4.00 L of an 8.30 M solution , Option A is correct .
To know more about molarity
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