Răspuns:
1.S2: c% = md*100/ms = 60*100/300=20%
mapa = ms-md=300-60=240 g
S3: c%=md*100/(md+mapa)
25*(md+125)=md*100
75*md=25*125
md=25*125/75=41.67g
ms=41.67+125=166.67 g
S4: c%=md*100/ms
ms=md*100/c%=90*100/30=300g
mapa= md-ms=300-90=210g
S5: c%=md*100/ms
ms=md+mapa=30+270=300g
c%=30*100/300=10%
S6: c%=md*100/ms
ms= md*100/c%=20*100/15=133.33g
mapa = ms-md=133.33-20=113.33g
S7: c%=md*100/ms
ms=mapa+md
md=ms-mapa=800-640=160g
c5= 160*100/800=20%
2.
a. omogen
b. 245 g
c. 45g
d. 10%
e. c%=md*100/ms
md = 40 g zahar
ms = mzahar + masa noua de apa (360g - 40g apa evaporata) = 40+320=360g
c%=40*100/360=11.11%
f. solutia initiala:
c1%=md1*100/ms1
12%=md1*100/350
md1 = 42 g zahar
md2 = 10 g zahar
mapa nou = 120g
cfinal = (md1+md2)*100/(ms1 +md2+mapa adaugat).
cfinal=52*100/(350+10+120)=10.83%
3.
c1%=md*100/ms1
10%=md*100/120
md=12 g sare (ramane constant)
mapa 1 = ms1- md1=120-12=108 g apa
c2% = 20% (concentratie dubla)
20%=12*100/ms2
ms2 = 60g
mapa2 = 60g - 12 g = 48 g apa
apa evaporata = mapa1-mapa2=108-48=60 g apa.
Explicație:
