[tdawg64]

My daughter is taking an online course to help with her chemistry credits. There are several problems thatkeep getting posted, but none of the solutions are covered in the online notes. Maybe someone here will be able to help. here are the questions that she is given:

1) Compute the boiling point of this solution:
    21.6g NiSO(base4) in 1.00 X 10(squared)g H2O  (assume 100%
    ionization.  (the freezing point of H2O is lowered by 1.86 degrees
    C per mole of solute.  The boiling point of h2O is raised 0.512
    degrees C per mole of solute.     (answer is degrees C)

2) Calculate the molecular mass of the nonionic solutes.
     8.02 grams of solute in 861 grams of water lower the freezing
     point to -0.430 degrees C.   (answer is g/mol)

3) Compute the freezing point of this solution.
     1.00*10(squared)g C(10)H(8)O(6)S(2)  (1,5
     naphthalenedisulfonic acid in 1.00*10(squared) H2O  (nonionizing
     solution).   answer is degrees C)
     
4) Calculate the osmotic pressure of this solution.
     18.6 grams of a solute with molecular mass of 8940 grams are 
     dissolved in enough water to make 1.00dm(cubed) of solution at
     25 degrees C. what is the osmotic pressure of the solution?   
     (answer is  atmospheres   TT)

These questions are completely beyond me or anyone else I've spoken with....even some of her teachers. Any help would be appreciated.
 

[Borek]

These are all about colligative properties. Tell her to register and to write what she knows about boiling point elevation and freezing point depression. We usually don't talk with parents, as it rarely helps kids to learn something

edit: colligative, not extensive. Sorry, English is my second language.

[tdawg64]

I can appreciate that. I just tried to get her registered, & the site allows 1 registration per computer. I have her beside me & asked her about boiling point elevation & freezing point depression. She has no idea about either of those topics. To be honest, she is trying to doa  credit recovery on-line & has received no help....from any source.

[Borek]

http://en.wikipedia.org/wiki/Boiling_point_elevation

http://en.wikipedia.org/wiki/Freezing-point_depression

These are very similar. If you dissolve something in liquid its freezing temperature goes down and boiling point goes up. Changes in temperature are proportional to the molality (concentration unit) of the dissolved substance. Each liquid has its own cryoscopic and ebuliometric constant - first tells how much freezing temp goes down in 1 molal solution, second tells how much boiling point goes up in 1 molal solution.