# An ammonia solution is 6.00 M and the density is 0.950 g mL. What is the mass/mass percent concentration of #NH_3# (17.03 g/mol)?

##### 1 Answer

#### Explanation:

The idea here is that you need to pick a sample *volume* of this solution and calculate

thetotal massof this samplethemass of ammoniait contains

To make the calculations easier, let's pick a **every milliliter** of solution has a mass of

The sample we've picked will have a mass of

#1000 color(red)(cancel(color(black)("mL"))) * "0.950 g"/(1color(red)(cancel(color(black)("mL")))) = "950 g"#

Now, you know that this solution has a **molarity** of **every liter**, which is the equivalent of **moles** of ammonia.

Since we've picked a sample of **moles** of ammonia. To convert this to *grams*, use the compound's **molar mass**

#6.00 color(red)(cancel(color(black)("moles NH"_3))) * "17.03 g"/(1color(red)(cancel(color(black)("mole NH"_3)))) = "102.18 g"#

Now, the solution's **percent concentration by mass**, *solute*, you get **per** **of solution**.

You already know how many grams of ammonia you have in

#100 color(red)(cancel(color(black)("g solution"))) * "102.18 g NH"_3/(950color(red)(cancel(color(black)("g solution")))) = "10.76 g NH"_3#

Therefore, you can say that the solution's mass by mass percent concentration is

#color(green)(bar(ul(|color(white)(a/a)color(black)("% m/m" = 10.8%"NH"_3)color(white)(a/a)|)))#

The answer is rounded to three **sig figs**.