word problem

Question

A 300-gram salt and water solution contains 25 g of salt. This mixture is left in the open air and 100 g of water evaporates from the solution. What is the percent concentration of salt in the remaining solution?

Answer 1

mass of salt and water = 300 g

 

mass of salt = 25 g

 

mass of water evaporated = 100 g. Thus mass of salt and water remaining = 300 - 100 = 200 g

 

% salt =  (mass salt / mass of salt and water remaining ) x 100

 

          = (25 g/200 g)  x 100  = 12.5