How many Kilograms of water must be added to 5.0 grams of oxalic acid (H2C2O4) to prepare a 0.40 Molality?

Answer 1

moles H2C2O4 = grams/molar mass.
Solve for mols.

m = moles/kg solvent
Solve for kg solvent.

Answer 2

(5.0 g) / (90.03488 H2C2O4/mol) / 0.40m = 45.01744

Answer 3

You punch a wrong button on your calculator. Try doing it in two steps instead of one.
5/90 = ??
??/0.4 =?? I get something about 0.139 kg.

Answer 4

Ok, I'm sorry. Not taking chemistry, but I'm taking a practice test, and I didn't know what to do. I want to be ready for next year. Thanks!