Question

Berapa fraksi mol 46 gram toluena(C7H8) dan 117 gram benzena(C6H6) dalam larutan? (Ar C=12; H=1)

Answer 1

Mol C7H8 = 0,5
mol C6H6 = 1,5

XC7H8 = 0,5/0,5+1,5 = 0,25
xC6H6 = 1,5/1,5+05 = 0,75

maka raksi molnya = 0,25 + 0,75 = 1

Answer 2

Mol C₇H₈ = massa/Mr = 46/(7*12 + 8*1) = 46/92 = 0,5 mol
mol C₆H₆ = massa/Mr = 117/(6*12 + 6*1) = 117/78 = 1,5 mol

X total = X C₇H₈ + X C₆H₆
           = {(mol C₇H₈) / (mol C₇H₈ + mol C₆H₆)} + {(mol C₆H₆) / (mol C₆H₆ + mol C₇H₈)}
           = {(0,5) / (0,5 + 1,5)} + {(1,5) / (1,5 + 0,5)}
           = {(0,5)/2} + {(1,5)/2}
           = 2/2
           = 1