posted by Tim .
A 15.0% (by mass) NaCl solution is available.. Determine what mass of solution should be used to obtain
a. 2.50 mole of NaCl
b. 25.0 g/mol of NaCl
A 15.0% NaCl solution means 15.0 g NaCl in 100 g solution. You want 2.50 moles NaCl.
1 mole NaCl is 58.44 grams so 2.50 moles = 2.50 x 58.44 = ?? grams (about 145 g or so) but you need to do it more accurately.
So you want to take 100 g soln x (145/15.0) = ??
Check my thinking.