posted by Jim_R on .
how many grams of NAOH are needed to make a 2.00 molal solution?
I got stuck here
2.00 molal=2.00 mole/kg
molecular weight of NAOH= 40g/mol
(2.00 g/molecular weight x kg) x 40 g/mol= stuck
You cant answer the question without knowing the amount of the 2m solution you need.
Doesn't it depend upon the amount of water you intend to use or the amount of solution one needs? (It does.)
So molal = # moles/kg solvent.
If you want 1 kg solvent, one needs 2.00 moles and that is 40.0 g. So 40.0 g NaOH/1.00 kg water makes a 2.00 m solution.
damn i never thought of kg of solution. your so smart.
2.00mol x 40 g/m= 80grams dissolved in water. so 80 grams of solute and 1000 water.
Chemistry doesnt make sense too me sometimes. Im use to thinking water =ml. But kg can be a solution too if you weigh it on an analytical balance.
Can help me learn to volumetric pipette. I can\t seem to control the water with my finger. It always goes over line. Very fustrating to start over and over.