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f 78.1 g of a sodium tetrafluoroborate is dissolved in 465 g of water solvent, c

ID: 824220 • Letter: F

Question

f 78.1 g of a sodium tetrafluoroborate is dissolved in 465 g of water solvent, calculate the freezing temperature (if below 0 oC, include the sign) of the solution. Consider if the solute is an electrolyte.



If 1010 g of a calcium iodide is dissolved in 1230 g of water solvent, calculate the magnitude (not the sign) of the freezing point depression of the solution. Consider if the solute is an electrolyte.



If 37.7 g of a ethylene glycol is dissolved in 233 g of cyclohexane solvent, calculate the freezing temperature (if below 0 oC, include the sign) of the solution. Consider if the solute is an electrolyte.



If 408 g of a ethylene glycol is dissolved in 2650 g of benzene solvent, calculate the magnitude (not the sign) of the boiling point elevation of the solution. Consider if the solute is an electrolyte.



If 1130 g of a potassium citrate is dissolved in 2430 g of water solvent, calculate the freezing temperature (if below 0 oC, include the sign) of the solution. Consider if the solute is an electrolyte.



If 1160 g of a aluminum sulfate is dissolved in 2640 g of water solvent, calculate the magnitude (not the sign) of the boiling point elevation of the solution. Consider if the solute is an electrolyte.


Molar Mass (g/mol) NaBF4 109.79 H2O 18.015 Solvent Melting Point (oC) 0.00 Boiling Point (oC) 100.00 Kf (oC/m) 1.858 Kb (oC/m) 0.512

Explanation / Answer

1)
DTf = i* Kf *molality
(0-Tf ) = 2*1.858*(78.1/109.79)(1000/465)

Tf = -5.684 0C

2)


DTf = i*Kf *molality
DTf = 3*1.858*(1010/293.89)1000/1230

DTf = 23.355


3)
DTf = i*Kf *molality
(0-Tf) = 3* 20*(37.7/62.068)(1000/233)

Tf = -106.39 0C
4)
DTb = i*Kb*molality
DTb = 3* 2.61(408/62.08)(1000/2650)
DTb = 12.946

5)

DTf = i*Kf *molality
(0-Tf) = 4*1.858*(1130/306.41)(1000/2430)
Tf = - 11.28 0C

6)
DTb = i*Kb*molality
(Tb-100) = 5*0.512*(1160/342.15)(1000/2640)
Tb = 103.285 0C