Waiting for answer This question has not been answered yet. You can hire a professional tutor to get the answer.

QUESTION

# 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 (17.04 g/mol)? Thank you

10.8%

Your strategy here will be to

• pick a sample of this ammonia solution
• use the solution's density to find the mass of the sample
• use the molar mass of ammonia to find the mass of solute

To make the calculations easier, pick a "1 L" sample of solution. As you know, is defined as moles of per liter of solution.

In this case, "1 L" of "6.00 M" ammonia solution will contain 6.00 moles of ammonia.

Now, you know that this solution has a of "0.950 g mL"^(-1). Use it to find the mass of "1 L" of solution

1 color(red)(cancel(color(black)("L"))) * (10^3color(red)(cancel(color(black)("mL"))))/(1color(red)(cancel(color(black)("L")))) * overbrace("0.950 g"/(1color(red)(cancel(color(black)("mL")))))^(color(blue)("the given density")) = "950 g"

You know that this sample contains 6.00 moles of ammonia, your solute. Use its molar mass to convert this to grams of solute

6.00 color(red)(cancel(color(black)("moles NH"_3))) * overbrace("17.04 g"/(1color(red)(cancel(color(black)("mole NH"_3)))))^(color(purple)("the given molar mass")) = "102.24 g"

Now, a solution's mass by mass , "% m/m", tells you how many grams of solute you have in "100 g" of solution.

color(blue)(|bar(ul(color(white)(a/a)"% m/m" = "grams of solute / 100 g solution"color(white)(a/a)|)))

In this case, you know that "950 g" of solution contain "102.24 g" of solute, which means that "100 g" of solution will contain

100 color(red)(cancel(color(black)("g solution"))) * ("102.24 g NH"_3)/(950color(red)(cancel(color(black)("g solution")))) = "10.8 g NH"_3

Since this is how many grams of ammonia you get per "100 g" of solution, you can say that the solution's "%m/m" will be equal to

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

The answer is rounded to three .