How do you figure freezing points and boiling points?

Boiling point.

delta T = i*Kb*m
where i = number of particles
Kb is boiling point constant
m = molality.

freezing point.
delta T = i*Kf*m
where Kf is freezing point constant. i and m have same meaning as above.

above posted by DrBob222

I don't understand i. Is it the sum of the charges on each element?

No, it's the number of particles in the solution. For example, NaCl would have i = 2 (for 1 Na+ + 1 Cl-), Na2SO4 would have i = 3. MOST organic molecules, and that's usually the scenario with these two formulas, i = 1 becuase the organic molecules don't ionize in water.

So if you have HC2H3O2 i would = 8?

You picked one that is not easy to do. No, it would not be 8. Actually, it is not an even number. Don't let this confuse you. This usually is used for non-volatile and non-ionizable substances.

The number for acetic acid is between 1 and 2 but closer to 1. HC2H3O2 ionizes into the H^+ ion and the C2H3O2^- ion but it isnn't 100% ionized. If 100% ionized it would be 2. If not ionized at all it would be 1. Actually it's about 1+ something but I don't know the acutal number. A fraction I know.