Respuesta :

Mass Percentage Definition. Mass percentage is one way of representing the concentration of an element in a compound or a component in a mixture. Mass percentage is calculated as the mass of a component divided by the total mass of the mixture, multiplied by 100%.
% mass = [( 35.04) / ( 100 + 35.04)] * 100
% mass = 25.95 %
Let's think about the solution first: it's composed of water (100 g) and 35.04 grams of NaCl  (in beaker for)

together it's 100+35.04=135.04

and NaCl in this solution is 35.04/135.04=25.95.

So the answer is 25.95