Question

What mass of water must be added to 5g of Nacl to make 5 percent mass by mass percentage of the solution

Answer 1

percentage concentration is as follows:

mass of solute       x 100%
mass of solution

mass of solute = 5g of NaCl
mass of solution = mass of NaCl + mass of water(let it be x)= 5g+xg
% concentration= 5%

Therefore,  5%  = 5g        by 100%
                            (5+x)g
                
                5= 500       cross multiply
                     5+x
            500= 25 + 5x
           500-25=5x
           5x=475 ......divide both sides by 5 to find x
              x = 95g

Therefore the mass of water to be added =  95 grams