Posted by Kristi on Saturday, November 26, 2011 at 8:34pm.
What is the mass percent of NaCl in a solution obtained by mixing 50g of this solution with 215g of H20?

Chemistry  DrBob222, Saturday, November 26, 2011 at 8:48pm
What's the concn to begin with?
current% x (50/265) = ?? 
Chemistry  Kristi, Saturday, November 26, 2011 at 9:50pm
do you then multiply that answer by 100?

Chemistry  DrBob222, Saturday, November 26, 2011 at 9:55pm
If you start with percent x (50/265) the answer is already in percent.
If you converted to a fraction first so the solution is
(%/100) x (50/265), yes, multiply that by 100. 
Chemistry  Kristi, Saturday, November 26, 2011 at 10:53pm
Thank you!