The question will be put in the description as it takes up too many characters in the title text box. The question that will be stated is a chemistry question.

Question

you need to prepare a 4m concentrated solution for a lab and only need 500 ml of total solution. if you use enough water to bring the volume to 500 ml, how many grams of sodium chloride would you need to dissolve the solution?

Answer 1

I'm going to assume that you meant to make a 4 M solution (not a 4 m solution). I assume this since we aren't given the density of the solution, so find m (molality) would not be directly feasible. So, to calculate M (molarity), all we need is moles and volume, which we can easily calculate.

4 M = 4 moles NaCl/liter solution

500 ml = 0.5 L of solution

moles NaCl needed to make 500 ml = 4 mol/L x 0.5 L = 2 mol NaCl required

grams NaCl needed = 2 mol NaCl x 58.4 g/mol = 116.8 g NaCl = 100 g (to 1 sig. fig.)