끓는점오름과 몰질량. 2.00 g 15.0 g CCl4 77.85℃

끓는점오름과 몰질량. 2.00 g 15.0 g CCl4 77.85℃

 

 

A 2.00 g sample of a large biomolecule was dissolved in 15.0 g carbon tetrachloride. The boiling point of this solution was determined to be 77.85°C. Calculate the molar mass of the biomolecule. For carbon tetrachloride, the boiling-point constant is 5.03 °C•kg/mol, and the boiling point of pure carbon tetrachloride is 76.50°C.

 

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ΔTb = Kb × m

( 참고 https://ywpop.tistory.com/1920 )

 

 

 

끓는점 오름(ΔTb) = 용액의 끓는점 - 순수한 용매의 끓는점

= 77.85 – 76.50

= 1.35℃

 

 

 

m = ΔTb / Kb

= 1.35℃ / (5.03 ℃•kg/mol)

= 0.26839 mol/kg

= 0.26839 m

 

 

 

몰랄농도 = 용질 mol수 / 용매 kg수

 

0.26839 m = ? mol / (15.0/1000 kg)

 

? = 0.26839 × (15.0/1000)

= 0.004026 mol

 

 

 

몰질량 = 질량 / 몰수

= 2.00 g / 0.004026 mol

= 496.8 g/mol

( 참고 https://ywpop.tistory.com/7738 )