The solution having the highest freezing point is ____.?

Question

a) 0.09 M urea
b) 0.05 M CaCl2
c) 0.04 M MgSO4
d) 0.005 M NaCl

The M is molarity correct? Heres how we did it in class

CaCl2 breaks up into Ca + 2Cl so .05x3 = .15M

same with the otheres and the last value are in order of

CaCl2 = .15M
urea = .09M
Mg2SO4=.08M
NaCl = .010M

from least to greatest, so is the answer NaCl or CaCl2, I believe he said it was NaCl lower concentration make freezing point go up?

I also have a boiling point question of the same effect so does lower concentration also make boiling point go up?

Answer 1

Based on Raoult's Law, which covers both freezing point depression and boiling point elevation, the solution with the highest concentration of ions will have the greatest effect. Thus the correct answer is (b) = CaCl2

Answer 2

Highest Freezing Point

Answer 3

The equation for freezing point depression is:

deltaT = - K*M

Since K is a property of the liquid, the only thing that matter in this problem is M. So, the larger M is, the lower the freezing point, meaning CaCl2 will have the lowest FP and NaCl will have the highest.

For boiling point elevation

deltaT = K*M

So the larger M, the higher the BP.

Answer 4

This Site Might Help You.

RE:
The solution having the highest freezing point is ____.?
a) 0.09 M urea
b) 0.05 M CaCl2
c) 0.04 M MgSO4
d) 0.005 M NaCl

The M is molarity correct? Heres how we did it in class

CaCl2 breaks up into Ca + 2Cl so .05x3 = .15M

same with the otheres and the last value are in order of

CaCl2 = .15M
urea = .09M
Mg2SO4=.08M
NaCl = .010M

from...

Answer 5

Its b). b, c and d are electrolytes, so they break in ions when they are hydrated. So, in b you get two times 0,05→0,10. In c you get 2 times 0,04→ 0,08, and in d you get 2 times 0,005 → 0,010
Remember this happens because you are dealing with colligative properties of solutions, and the thing that matters is the "collection" of particules (it is not the same having 1 mol of salt than 1 mol of urea)
a) is not an electrolyte. Therefore, it is not as big as 0,10 of CaCl2. B is the answer, since you get 1mol of Ca and 1mol of Cl2

Answer 6

NaCl

Answer 7

Its a)

Answer 8

d)