Hey guys I was wondering if you guys know the answer to this:
Which of the following is NOT true of colligative properties? Colligative properties are...
A. independent of the chemical identity of the solute.
B. responsible for lowering the vapor pressure of a solution versus the vapor pressure of the pure solvent.
C. dependent on the molar mass of the solute.
D. dependent on the mass of solute present.
E. all of these are true.
I am thinking it is D?
I believe you need to rethink this question. For example, in the freezing point depression, we have
delta T = Kf* molality
and molality = moles solute/kg solvent
and moles solute = grams/molar mass.
So I would think adding grams makes more moles and more moles increases molality and more molality increases delta T. So it looks to me that it IS dependent upon the mass of the solute.
The answer is C. I had got it wrong, but I looked at the posted correct answers and it says the not true statement is(not sure why):
dependent on the molar mass of the solute.
To determine which of the options is NOT true, we can evaluate each statement individually.
Option A states that colligative properties are independent of the chemical identity of the solute. This statement is true – colligative properties, such as boiling point elevation or freezing point depression, depend solely on the concentration of solute particles in a solution, regardless of their chemical nature.
Option B states that colligative properties are responsible for lowering the vapor pressure of a solution compared to the vapor pressure of the pure solvent. This statement is also true – adding a non-volatile solute to a solvent diminishes the number of solvent particles at the surface, resulting in a decrease in vapor pressure.
Option C states that colligative properties are dependent on the molar mass of the solute. This statement is true – colligative properties are based on the number of solute particles present in a solution, with higher molar mass solutes having a greater impact on these properties.
Option D states that colligative properties are dependent on the mass of solute present. This statement is NOT true. It is incorrect to say that colligative properties depend on the mass of the solute, as they rely solely on the concentration of solute particles.
Therefore, the answer to your question is option D.