Asolution contains 85.0 g of nano3, and has a volume of 750. ml. find the molarity of the solution

Molarity is defined as the number of moles in 1 L of solution.
Mass of NaNO₃ present - 85.0 g 
Molar mass of NaNO₃ - 85 g/mol
The number of NaNO₃ moles - 85.0 g / 85 g/mol = 1 mol 
Volume of solution - 750 mL
The number of moles in 0.750 mL - 1 mol
Therefore in 1 L solution, number of NaNO₃ moles - 1/0.75 = 1.33 mol
Therefore molarity of solution - 1.33 M

Mg-26 and mg-24 are pair of isotopes. isotopes are defined as atoms of the same element having same atomic number but different mass number. i hope that was .