Question

What mass of KCl is dissolved in 250. mL of a solution that is 4.00 % by mass/volume?

Answer 1

I attempted at the problem, is it 10.0g?

Answer 2

Very good.
4.00 g/100 mL is a 4% solution.
So 250 mL will have
4.00 x (250/100) = 10.0 grams.