Question

calculate the mass, in grams, of NaCl present in each of the following solutions.
6.25 g of 11.5% NaCl solution

452 g of 12.3% NaCl solution

please show me how to do these. Thanks.

Answer 1

11.5% NaCl(w/w) means 11.5 g NaCl in 100 g soln.
11.5 g x 6.25g/100g = ??g in 6.25 g soln.
OR
(g solute/g soln)*100 = percent
(x g NaCl/6.25g soln)*100 = 11.5%
(x g NaCl/6.25 g soln) = 0.115
x g NaCl = 0.115 x 6.25 = ??

Answer 2

you will get the same answer
11.5*6.25=71.875
71.875/100=0.71875

or
0.115*6.25=0.71875