First, determine the number of moles of gold.
Number of moles = [tex]\frac{given mass in g}{molar mass}[/tex]
Given mass of gold =[tex]6 \times 10^{9} g[/tex]
Molar mass of gold = 196.97 g/mol
Put the values,
Number of moles of gold = [tex]\frac{6 \times 10^{9} g}{196.97 g/mol}[/tex]
= [tex]0.03046\times 10^{9} mole[/tex] or [tex]3.046\times 10^{7} moles[/tex]
Now, molarity = [tex]\frac{moles of solute}{volume of the solution in liters}[/tex]
Put the values, volume of ocean =[tex]1.5 \times 10^{21} L[/tex]
Molarity = [tex]\frac{3.046\times 10^{7} moles}{1.5 \times 10^{21} L}[/tex]
= [tex]2.03\times 10^{-14} M[/tex]
Thus, average molar concentration = [tex]2.03\times 10^{-14} M[/tex]
