Question

Dau 40 de puncte va roggg
Dupa terminarea lucrarii de laborator,elevii recupereaza solutiile de piatra vanata cu care au lucrat,punandu-le intr-un vas. Ce concentratie are solutia
din vasul de recuperare,stiind ca:
solutia 1 contine 20 g de apa si c1=20%
solutia 2 contine 30 g apa si c2=40%

Answer 1

stim ca ms=md+mapa, pentru solutiile apoase
ms1=md1+20
c1/100=md1/ms1=md1/(md1+20)
md1+20=md1*100/c1=5md1
4md1=20 => md1=5g CuSO4
=> ms1=20+5=25g solutie CuSO4
ms2=md2+mapa=md2+30
c2/100=md2/ms2 => ms2=md2*100/c
md2+30=md2*100/40=2,5md2
1,5md2=30 => md2=20g CuSO4
=> ms2=30+20=50g solutie CuSO4
mdf=md1+md2=25g CuSO4
msf=ms1+ms2=50+25=75g solutie CuSO4
cf=mdf*100/msf=25*100/75=33,33%