Respuesta :
Answer:
The number of moles =
[tex]Moles=4.97\times 10^{-8}[/tex]
The number of molecules =
[tex]Molecules = 2.99\times 10^{16}[/tex]
Explanation:
Volume of the sphere is given by :
[tex]V=\frac{4}{3}\pi r^{3}[/tex]
here, r = radius of the sphere
[tex]radius=\frac{diameter}{2}[/tex]
[tex]radius=\frac{6.0}{2}[/tex]
Radius = 3 mm
r = 3 mm
1 mm = 0.01 dm (1 millimeter = 0.001 decimeter)
3 mm = 3 x 0.01 dm = 0.03 dm
r = 0.03 dm
("volume must be in dm^3 , this is the reason radius is changed into dm"
"this is done because 1 dm^3 = 1 liter and concentration is always measured in liters")
[tex]V=\frac{4}{3}\pi 0.03^{3}[/tex]
[tex]V=\frac{4}{3}\pi 2.7\times 10^{-5}[/tex]
[tex]V=1.13\times 10^{-4}dm^{3}[/tex]
[tex]V=1.13\times 10^{-4}L[/tex] (1 L = 1 dm3)
Now, concentration "C"=
[tex]C=4.4\times 10^{-4}moles/liter[/tex]
The concentration is given by the formula :
[tex]C=\frac{moles}{Volume(L)}[/tex]
This is also written as,
[tex]Moles = C\times Volume[/tex]
[tex]Moles=1.13\times 10^{-4}\times 4.4\times 10^{-4}[/tex]
[tex]Moles=4.97\times 10^{-8}[/tex]moles
One mole of the substance contain "Na"(= Avogadro number of molecules)
So, "n" mole of substance contain =( n x Na )
[tex]N_{a}=6.022\times 10^{23}[/tex]
Molecules =
[tex]Molecule=4.97\times 10^{-8}\times 6.022\times 10^{23}[/tex]
[tex]Molecules = 2.99\times 10^{16}[/tex] molecules
