Answer:
A) [tex]6.5\times 10^{23}\ \text{molecules}[/tex]
Explanation:
m = Mass of water = 38.9
M = Molar mass of water = 18 g/mol
[tex]N_A[/tex] = Avogadro's number = [tex]6.022\times 10^{23}\ \text{mol}^{-1}[/tex]
The reaction of electrolysis would be
[tex]2H_2O(l)\rightarrow 2H_2(g)+O_2(g)[/tex]
Number of moles of [tex]H_2O[/tex]
[tex]n=\dfrac{m}{M}\\\Rightarrow n=\dfrac{38.9}{18}\ \text{mol}[/tex]
From the reaction it can be seen that 2 moles of [tex]H_2O[/tex] gives 1 mole of [tex]O_2[/tex]
So, number of moles of [tex]O_2[/tex] produced is
[tex]\dfrac{38.9}{18}\times \dfrac{1}{2}=1.081\ \text{mol}[/tex]
Number of molecules
[tex]1.081N_A=1.081\times 6.022\times 10^{23}\\ =6.5\times 10^{23}[/tex]
So, [tex]6.5\times 10^{23}\ \text{molecules}[/tex] of oxygen is produced.
