Calculate the mass percent of a nacl solution in which 140g of nacl is dissolved in 4.50l of water at 25c (density = 0.997g/ml).

Mass percent is one way of expressing concentration of a solution. It is expressed as the mass of solute per mass of solution. For this case, mass percent is calculated as follows:

% mass = 140 g NaCl / (140 g NaCl + 4500 mL ( 0.997 g/mL)) x 100
% mass = 3.03 %