Question

A student determines the freezing point of a solution of 2.07 g ofnaphthalene in 27.00 g of paradichlorobenzene. they gave a set oftemp-time readings and I had to graph them. the time readings wereto 1.0 minutes and the temp readings were also to 1.0 C.

Then I found the Freezing point of the solution to be 49.1 C.

a.) what is the freezing point depression, Delta T, given that thefreezing point for pure paradichlorbenzene is 53.0 C?

I got 3.9 C by subtracting 53-49.1

b.) using Kf = 7.10 C/m(C kg/mole) for Paradichlorobenzene and m =delta T / Kf, calculate the molarity of the naphthalene.

I got .55 m

c.) using MM= Kf(number grams solute)/((number kg solvent)(deltaT)) calculate the MM of naphthalene

I got ~ 140 g/mol

d.) if part c consistent with the real molar mass of 128 g/mol?

e.)calculate the percent error that is introduced in the calculatedmolecular weight, if a 1.0 C error exists in the determination ofthe delta T? be very specific. show the calculation for 1.0 Chigher and 1.0 C lower.

I got 9.4 % ( (140-128)/128 x 100 = 9.4 %)

if + 1.0C i got 13.2 %

if - 1.0 C i got 46.6 %

f.) how accurately must we determine delta T in order to be assuredof an accurate value for the molecular weight? be very specific bysupplying a numerical value. explain your rational.

g.) what changes or refinements in the experimental procedure doyou recommend to attain the desired accuracy in delta T? be veryspecific,

I AM SO SORRY THIS IS SO LONG! PLEASE COMFIRM THAT I HAVE BEENDOING THIS RIGHT. IF I AM NOT, PLEASE SHOW STEPS. I REALLY JUSTNEED HELP ON F AND G, BUT I PUT THE REST THERE SO YOU CAN SEE MYANSWERES. THANK YOU SO MUCH!!!!! :)