Question

Oblicz stężenie procentowe roztworu otrzymanego w wyniku zamieszania 250g roztworu o stężeniu 20% i 750g roztworu o stężeniu 40%.

Answer 1

mr1=250g
Cp1=20%
ms1=?
mr2=750g
Cp2=40%
ms2=?

ms1=Cp1*mr1/100%
ms1=20%*250g/100%
ms1=50g

ms2=Cp2*mr2/100%
ms2=40%*750g/100%
ms2=300g

Cpx=(ms1+ms2)*100%/(mr1+mr2)
Cpx=(50g+300g)*100%/(250g+750g)
Cpx=350g*100%/1000g
Cpx=35

Answer 2

250g 20%..................40 - x

....................x%

750g 40%...................x - 20

250/750 = 40-x/x-20

250(x-20) = 750(40-x)

250x-5000 = 30000-750x

1000x = 35000

x = 35%