How do you get the boiling point?

Question

What is the boiling point of a solution of 25.0 g of C3H8O3 in 250 g C2H5OH? Kb for C2H5OH is 1.19ºC/m and the boiling point of C2H5OH is 78ºC.

and how do you get delta???

Answer 1

ΔTb= Kb*m

m=molality = mole solute /kg of solvent

So if G is the mass of solvent in grams,
m= 1000*mole/G
but mole= g/MW
where g is the grams of solute and MW the molecular weight of the solute

so
m= 1000 *g/(MW*G) and
ΔTb= Kb1000*g/(MW*G) =1.19*1000*25 / (104*250)=>
ΔTb=1.14 C

The boiling point of the solution is
Tb= Tb0+ΔTb =78+1.14 = 79.14 C

How did you put the degree sign?