Vitamin K is involved in normal blood clotting. When 1.56 g of vitamin K is dissolved in 25.0 g of camphor, the freezing point of the solution is lowered by 5.23 °C. . Calculate the molar mass of vitamin K.
I posted this yesterday but I got the wrong answer and could use some step by step help?
Thanks
I think I answered your question. The easy way to find the error is for you to post your work and let me check it. I'm happy to do that for you.
when Im getting my Kf do i change it from Celsius to Kelvin before i do my calculation?
You can but it doesn't matter. I think Kf for camphor is about 38 C/m (37.7 maybe?) or something like that.
What I meant was that Kf for camphor is 37.7 celsius/m or 37.7 Kelvin/m
Im sure i did this wrong but this is what i did
deltaT=Kfm
m=mols solute/ kg solvent
1.56g vitamin k/83.8g= 0.019
m=0.019/ 0.025 = 0.76
delta T=Kfm
-5.23=37.8m
-5.23-37.8 =m
m=-43.03
I think I wrote this:
delta T = Kf*m
Substitute and solve for m = molality
m = mols solute/kg solvent
Substitute and solve for mols solute.
mols = grams/molar mass
Substitute and solve for molar mass.
I don't think you followed the steps.
Take it one step at a time.
delta T = K*m
5.23 = 37.7*m
m = 5.23/37.7 = about 0.138m
Next.
m = mols solute/kg solvent
0.138 = mols solute/0.025
mols solute = 0.138 x 0.025 = about 0.00346 mols
Next:
mol = grams/molar mass
0.00346 mols = 1.56g/molar mass
molar mass = ?
nope. That isn't the way math works.
so i do 0.00346mols x 1.56 = 0.00539?
no.
0.00346 mols = 1.56g/molar mass
molar mass = 1.56/0.00346 =?