What is the concentration in m/m% of a solution prepared from 50.0 g NaCl and 150.0 g of water?

1 Answer
Jun 7, 2017

Answer:

#25.0%#

Explanation:

A solution's mass by mass percent concentration, #"m/m%"#, tells you the number of grams of solute present for every #"100 g"# of solution.

Your solution contains two substances: sodium chloride, #"NaCl"#, the solute, and water, the solvent. To find the total mass of the solution, add the mass of the solute and the mass of the solvent.

#"mass solution = 50.0 g + 150.0 g"#

#"mass solution = 200.0 g"#

Now, this solution contains #"50.0 g"# of solute in

#"200.0 g" = color(red)(2) * "100.0 g"#

of solution. This means that #"100.0 g"# of solution will contain

#"50.0 g"/color(red)(2) = "25.0 g"#

of solute. Since this represents the amount of solute present in #"100.0 g"# of solution, you can say that the mass by mass percent concentration is equal to

#color(darkgreen)(ul(color(black)("m/m% = 25.0% NaCl")))#

The answer is rounded to three sig figs.