i got lost first i thought i understand it then i don't Please help me step by step

Question

A solution is prepared by dissolving 10.98g of MgCl₂in 646 mL of water. The total mass of the solution is 656.98g, and the total volume is 651 mL.

A. what is m/m percent concentration of MgCl₂?

B.what is m/v percent concentration of MgCl₂?

C. what is the molarity of MgCl₂?

Answer 1

mass/mass % MgCl₂ = mass MgCl₂/total mass of solution (x100%) = 10.98 g/656.98 g(x100%) = 1.671%

mass/volume % MgCl₂ = mass MgCl₂/100 ml solution = 10.98 g/651 ml (x100 ml) = 1.69%

molarity = moles MgCl₂/liter of solution = 10.98 g MgCl₂ x 1 mol/95.211 g /0.651 L = 0.1771 M