C7H8 0.867 g/mL C4H4S 1.065 g/mL 8.10 g 250.0 mL

C7H8 0.867 g/mL C4H4S 1.065 g/mL 8.10 g 250.0 mL

 

 

The density of toluene (C7H8) is 0.867 g/mL,

and the density of thiophene (C4H4S) is 1.065 g/mL.

A solution is made by dissolving 8.10 g of thiophene in 250.0 mL of toluene.

Calculate the mole fraction of thiophene in the solution.

mole fraction of C4H4S =

molality of C4H4S =

Assuming that the volumes of the solute and solvent are additive,

what is the molarity of thiophene in the solution?

 

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C4H4S의 몰질량 = 84.14 g/mol

8.10 g / (84.14 g/mol) = 0.0963 mol 용질

( 참고 https://ywpop.tistory.com/7738 )

 

 

 

C7H8의 몰질량 = 92.14 g/mol

250.0 mL × (0.867 g/mL) / (92.14 g/mol) = 2.3524 mol 용매

 

 

 

C4H4S의 몰분율 = 0.0963 / (0.0963 + 2.3524) = 0.0393

( 참고: 몰분율 https://ywpop.tistory.com/2659 )

 

 

 

몰랄농도 = 용질 mol수 / 용매 kg수

= 0.0963 mol / [250.0 mL × (0.867 g/mL) / 1000]

= 0.444 mol/kg

= 0.444 m

 

 

 

8.10 g / (1.065 g/mL) = 7.6056 mL C4H4S (용질)

 

 

 

용액의 부피 = 용질의 부피 + 용매의 부피

= 7.6056 + 250.0 = 257.6056 mL

= 0.2576056 L

 

 

 

몰농도 = 용질 mol수 / 용액 L수

= 0.0963 mol / 0.2576056 L

= 0.374 mol/L

= 0.374 M