Vitamin K is involved in normal blood clotting. When 1.55 g of vitamin K is diss
ID: 988490 • Letter: V
Question
Vitamin K is involved in normal blood clotting. When 1.55 g of vitamin K is dissolved in 25.0 g of camphor, the freezing point of the solution is lowered by 5.21 degree C. The freezing point and K_f constant for camphor can be found here. Calculate the molar mass of vitamin K. First find the molality, m (or b), using Delta T_f and K_f. Next, recall that molality is the moles of solute per kilogram of solvent. Thus, you can multiply the molality by the kilograms of solvent to get the moles of solute. Finally, use the mass and moles of the the solute to get the molar mass in grams per mole.Explanation / Answer
depression in freezing point:
delta Tf = 5.21 oC
Kf for camphor = 40 oC/m
use:
delta Tf = Kf * m
5.21 = 40* m
m = 0.13025 molal
mass of solvent = 25 g = 0.025 Kg
mass of vitamin K = 1.55 g
Molar mass of vitamin K = M g
number of moles of vitamin K = mass / molar masss
= 1.55/M
use:
molality= number of moles / mass of solvent in Kg
0.13025 = (1.55/(M*0.025))
M = 476.008 g/mol
Answer: 476 g/mol
Your answer was perfectly correct mate
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