Question

se amestecă doua soluții alcool de concentrație 20% , respectiv 40% in raport masic 1:2 obținându-se 900g soluție. Calculeaza concentratia procentuala a soluției rezultate. Va rog.. repede!

Answer 1

c1=md1/ms1*100
=>md1=ms1*20/100=0,2ms1
c2=md2/ms2*100
=>md2=ms2*40/100=0,4ms2
ms1+ms2=900
ms1/ms2 = 1/2 => ms2 = 2ms1
c% final = md final/ ms final * 100
md final = md1+md2 = 0,2ms1+0,8ms1=ms1
ms final = ms1+ms2=ms1+2ms1=3ms1
c% = ms1/3ms1*100 = 33,333%

Answer 2

Cp1=20%
Cp2=40%

ms1+ms2=900g sol. ==> ms1+2ms1=900==>3ms1=900==>ms1=900/3=>ms1=300g sol.

ms1/ms2=1/2==>ms2=2ms1==>ms2=2*300=600g sol.

Cp1=md1/ms1*100==>md1=Cp1*ms1/100=20*300/100=60g

Cp2=md2/ms2*100==>md2=Cp2*ms2/100=40*600/100=240g 

mdf=md1+md2=60+240=300g
msf=900g

Cpf=mdf/msf*100=300/900*100=33.33%