Question

Could someone please help me with this question: Ascorbic acid (vitamin C) in waterC6H8O6, 176.1 g/mol molarity = 1.92 M d = 1.22 g/mLmolality = ?

Answer 1

Do you know what the answer is? I don't think its right, but I got 3.61 messing around... I can't seem to get my units to cancel.

Answer 2

For the absorbic acid problem the answer is 2.18.

Answer 3

Alright, I'm over complicating it, hold on, give me a few minutes, I'll get the answer.

Answer 4

Yes! I got 2.17, but thats close enough. Let me post the work.

Answer 5

Ascorbic Acid: C6H8O2
Molar mass: 176.1 g/mol
Molarity: 1.92 M = 1.92 mol/L
Density: 1.22 g/mL = 1220 g/L

From the density, 1 liter of this solution would weigh 1220 g. There would be 1.92 moles of ascorbic acid in 1 liter of this solution.
1.92 mol/L * 176.1 g/mol = 338.112 g/L C6H8O2
1220 g solution - 338.112 g C6H8O2 = 881.888 g H2O (solvent) = 0.881888 kg H2O

Molality = moles solute / kg solvent
\[m = \frac {1.92 mol C_6H_8O_2}{0.881888 kg H_2 O} \approx 2.17 mol/kg\]

Answer 6

Does that make sense?

Answer 7

Yes- this makes sense now- thank you a ton, I have an exam on this topic tomorrow morning!

Answer 8

Alright, I wish you the best of luck! Ace that exam! :D

Answer 9

Thank you- will do! :)