CHEMISTRY: Is this true or false? :)))))))?

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Sheyna

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"Dissolving a non-volatile solute in a solvent has the effect of extending the temperature range over which the solvent remains in the liquid phase."

Is it true or false and can you explain why??? I don't get it.

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One more: :)
Assuming that each system behaves ideally, which solution (0.25 M HCl or 0.25 C3H8O3) would have lower freezing point?
I don't get how would I know this or figure it out? ?







THANK YOUUUUUUUUUUUUUU.
 
"Dissolving a non-volatile solute in a solvent has the effect of extending the temperature range over which the solvent remains in the liquid phase."

Sure, that's true, because a solution will have a lower freezing point and a higher boiling point. Check out "colligative properties" and "boiling point elevation" and "freezing point depression".

As for your second question, the greater the concentration of particles in solution, the greater the change in FP or BP.

DT = i x k(f) x m .... where DT is the change in temperature from the normal freezing point, i = van't Hoff factor, k(f) is the freezing point constant for the solvent, and m is the molality of the solute.

The i for HCl is about 2 while for C3H8O3 it is essentially 1. HCl dissociates into two particles H+ and Cl-), while C3H8O3 may not dissociate to any extent, at all. The greater i for HCl, despite the same concentration of solutes, will give a greater DT for HCl.
 
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