in toate problemele se utilizeaza relatia:
c(w)=mdx100/ms, unde ms= md+m,apa
1.se cere md si V.apa
md= cxms/100---> md= 2x70/100=1,4g zahar
m,a= ms-md=> 70-1,4g= 68,6g; Vapa= 68,6ml,deoarece densitatea apei este 1 g/ml
CONTINUA......................
2. se cere ms
ms= mdx100/c---> ms=100x100/0,1=100x100x10= 100000g solutie
CONTINUA
3.se cere c%
ms= m,apa+md=>800g+1,5g= 801,5g
c= 1,5x100/801,5=........................calculeaza !!!!