Clearing up extrinsic (colligative) and intrinsic properites

[omarski]

I just want to clear up what boiling point is, and from what I understand, it is an intrinsic property that is dependent on the molecule, correct?
However, an extrinsic or colligative property would be boiling point elevation or freezing pt depression, as it depends on the ratio of solute particles to solvent particles.

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[BioForLife]

Correct. Intrinsic properties of a compound are independent of amount or conditions. Extrinsic properties vary by scale/ratio.

 

[omarski]

Thank you! I just needed to verify I approached it correctly since Boiling pt. and boiling pt elevation sound really similar.

For density, can you say that the density of a molecule is an intrinsic property, however when looking at a solution, could you say the density of the solution is extrinsic as volume varies under different tempartures? And since D = m/v , volume would change and as a result the density would too?

 

[BioForLife]

Thank you! I just needed to verify I approached it correctly since Boiling pt. and boiling pt elevation sound really similar.

For density, can you say that the density of a molecule is an intrinsic property, however when looking at a solution, could you say the density of the solution is extrinsic as volume varies under different tempartures? And since D = m/v , volume would change and as a result the density would too?

Density is always intrinsic regardless of whether you're looking at molecules or a solution.

Let's use sodium as an example. Mass is extrinsic because it depends on how much sodium you have. More sodium=more mass. Volume is extrinsic as well, because more sodium will take up more space. When you divide these two extrinsic properties, however, the result is an intrinsic property (density). Density does change as a result of temp changes, but this change is independent of the amount of sodium you started with. You can add more sodium into the solution and (provided you maintain the same concentration of solution), it will not change. Of course, if you go from a 5% NaCl solution to a 30% NaCl solution, density will increase since there is more mass in a given volume.

So in short, intrinsic doesn't mean the value doesn't ever change, since, as you mentioned, density is dependent on temperature. It just means that the property (density) is independent of the amount you started with (amount of sodium in this case).