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What is the boiling point elevation constant, Kb, of diethyl ether if 38.2 g of the nonelectrolyte benzophenone, C6H5COC6H5, dissolved in 330. g of diethyl ether produces a solution that boils at 35.7°C? Use molar masses with at least as many significant figures as the data given.

Respuesta :

Answer: the boiling point elevation constant is [tex]1.73^0C/m[/tex]

Explanation:

Elevation in boiling point is given by:

[tex]\Delta T_b=i\times K_b\times m[/tex]

[tex]\Delta T_b=T_b-T_b^0=[/tex] = Elevation in boling point

i= vant hoff factor = 1 (for non electrolyte)

[tex]K_b[/tex] =boiling point constant = ?

m= molality

[tex]\Delta T_b=i\times K_b\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}[/tex]

Weight of solvent (diethylether)= 330 g = 0.33 kg

Molar mass of solute (benzophenone)= 182 g/mol

Mass of solute (benzophenone) = 38.2 g

[tex](35.7-34.6)^0C=1\times K_b\times \frac{38.2g}{182g/mol\times 0.33kg}[/tex]

[tex]K_b=1.73^0C/m[/tex]

Thus the boiling point elevation constant is [tex]1.73^0C/m[/tex]

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