# Question #8df2c

##### 1 Answer

Here's what I got.

#### Explanation:

A solution's **mass by volume percent concentration**,

In your case, you know that your solution contains

To do that, use the known composition as a *conversion factor*.

#100 color(red)(cancel(color(black)("mL solution"))) * "30 g NaCl"/(200color(red)(cancel(color(black)("mL solution")))) = "15 g NaCl"#

This means that your solution's mass by volume percent concentration is equal to

#color(darkgreen)(ul(color(black)("% m/v = 20% NaCl")))#

Keep in mind that you **must** round the answer to one **significant figure** because that's how many sig figs you have for your data.

To find the concentration of the solution in *grams per liter*, use the fact that

#"1 L" = 10^3 color(white)(.)"mL"#

Since you already know that

#10^3 color(red)(cancel(color(black)("mL solution"))) * "30 g NaCl"/(200color(red)(cancel(color(black)("mL solution")))) = "150 g NaCl"#

Therefore, this solution has a concentration of

#color(darkgreen)(ul(color(black)("concentration = 200 g L"^(-1)color(white)(.)"NaCl")))#

Once again, the answer must be rounded to one **significant figure**.