Question

un amestec de mono clor toluen si dicloro toluen are 40 % clor. care este compozitia procentuala de masa a amestecului?

Answer 1

monoclortoluen : C7H7Cl M=7*12+7+35.5=126.5
diclortoluen: C7H6Cl2 M=7*12+6+35.5*2=161
Se considera 100 g amestec monoclortoluen si diclortoluen. (x+y=100)
 126.5 g monoclortoluen ...... 35.5 g Cl
    x g monoclortoluen ...........  a g Cl  = 35.5x/126.5
 161  g diclortoluen    .........  35.5*2 g Cl
    y g diclortolue ................    b g Cl  =  35.5*2y/161
a+b = 40 ( amestecul are 40 % Cl - ipoteza)
<=> 35.5x/126 + 35.5*2y/161 = 40 <=> 0.28x+0.44y=40
x+y=100 => x=100-y
Inlocuim in prima relatie => 0.28(100-y)+0.44y=40 <=> 28-0.28y+0.44y=40 <=>
y=75 ; x=100-75 = 25
Amestecul contine 25% monoclortoluen si 75% diclortoluen.