Super Saturated Fun Sheet

Question

if you use 275 grams of sodium fluoride (NaF) and dissolve this into 3620 grams of water, what will be the change in the boiling point of your solution? Assume the Kb of water is 0.51 degrees/m

Answer 1

∆T = imK

∆T = change in boiling point = ?

i = van't Hoff factor = 2 for NaF since it produces 2 particles (Na⁺ and F^-)

m = molality = mole/kg = 275 g NaF x 1 mol/42.0 g = 6.55 mol / 3.62 kg = 1.81 m

K = freezing constant = 0.51º/m

∆T = (2)(1.81)(0.51)

∆T = +1.8º (answer)