Wondering how you calculate boiling point elevation?

L

Lori Osachuk

New member
For the following:
1.000 mol/kg sucrose (non-ionic)
0.500 mol/kg NaCl
5.000 mol/kg CaCl2

How do you calculate:
1. the total molality of particles in solution
2. the freezing point depression (Kf = 1.86 °C . kg/mol)
3. the boiling point elevation (Kb = 0.51 °C . kg/mol)

So confused..any help would be appreciated!
 
to calculate boiling point elevation, use the formula delta Tb = iKb X m
where delta Tb is the boiling point elevation(temp difference) i is the bond number and m is the molality (no of moles. / kg of solvant). kb is a constant.
sucrose has covalent bonds therefore i = 1
moles / kg is molality therefore m = 1
plug these values into the equation.

NaCl has ionic bonds but only one therefore i =1
CaCl2 has two ionic bonds therefore i = 2
 
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