[OTI]

I just have a question about how to calculate the freezing and boiling temps of stuff.

I learned this equation: ΔT_f/b = m × K_f

So my question is, after I get ΔT_f/b, do I add or subtract to the freezing or boiling point of water? (assume that I am finding the freezing/boiling point of dissolved in water)

[mikasaur]

http://www.foothill.edu/attach/psme/sinha.fpdepression.pdf

The freezing point of a solvent decreases as you add solute to it. This is why we put salt on icy roads http://www.scientificamerican.com/article/why-do-we-put-salt-on-icy/

[OTI]

So basically, I'm always going to subtract ΔT_f from the freezing point and add ΔT_b to the boiling point?

[mikasaur]

Yep.

https://en.m.wikipedia.org/wiki/Boiling-point_elevation