Given :
Mass of methanol ( [tex]CH_3OH[/tex] ) , m = 5 kg = 5000 g .
Volume of water , [tex]V=2\ m^3=2000\ L[/tex] .
To Find :
Molecules of methanol per liter of water .
Solution :
Moles of methanol , [tex]n=\dfrac{5000}{32}=156.25\ mol[/tex] .
We know , 1 mole of a substance contains [tex]6.022\times 10^{23}\ mol^{-1}[/tex] .
So , total number of molecules :
[tex]M=156.25\times 6.022\times 10^{23}\\\\M=9.41\times 10^{25}[/tex]
Number of molecules per liter :
[tex]\dfrac{9.41\times 10^{25}}{2000}\\\\4.705\times 10^{22}[/tex]
Hence , this is the required solution .
