58.5g of sodium iodide are dissolved in 0.5dm3. what concentration would this be?

percent by mass = (mass of solute / mass of solution) * 100 %

mass of solute=58.5 g

density (H₂O) = 1 g/cm³ * (1000 cm³/1dm³) = 1000 g/dm³

mass of solvent (H₂O) = 0.5 dm³ * (1000 g/dm³) = 500 g

mass of solution=mass of solvent + mass of solut

mass of solution=58.5 g+500 g=558.5 g

% mass = (58.5 g/558.5 g) * 100%=10.47% of Na.

solution: 10.47% of Na.