Question

Cate grame de apa trebuie adaugate peste 50g solutie de sodă caustica de concentratie 40% astfel incat concentratia sa devina 5%?Va rog nu stiu cum sa o fac si e urgent...

Answer 1

ms=50g
c1=40%
c2=5%
———————
ma adăugat=?

c=mdx100:ms => md=cxms:100
md=c1xms:100
md=40x50:100
md=20 => ma1=30g

c=mdx100:ms => ms=mdx100:c
ms2=mdx100:c2
ms2=20x100:5
ms2=400
ms=md + ma

=> ms2= md + ma2
ma2=ms2-md
ma2=400-20
ma2=380
Dar ma2=ma1+ma adăugat
ma adăugat= ma2-ma1
ma adaugat= 380-30
ma adaugat=350g



Trebuie sa se adauge 350g



Sper ca te-am ajutat