Explanation:
Let us assume that the volume of given aqueous solution is 7.5 L.
Therefore, according to Henry's law, the relation between concentration and pressure is as follows.
C =
where, pressure (P) = 760 torr = 1 atm
According to Henry's law, constants for gases in water at are as follows.
= 0.21 atm = 0.21 bar
= 0.78 atm = 0.78 bar
for
=
for
=
Since, 21% oxygen is present in air so, its mass will be 0.21 g. Similarly, 78% nitrogen means the mass of nitrogen is 0.78 g.
Therefore, concebtrations will be calculated as follows.
Now, we will calculate the number of moles as follows.
mol
mol
As the molar mass of = 32 g/mol
Hence, mass of oxygen will be as follows.
Mass of
= 63.84 mg
As the molar mass of = 28
Mass of = 102.5 mg
Thus, we can conclude that mass of oxygen is 63.84 mg and nitrogen is 102.5 mg.