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1 Cate grame de solutie cu concentratia 3 la suta se obtin prin dizolvarea a 12 g sare de lamaie in apa.
2 cate grame de sare se dizolva in apa pentru a se obtine 200g solutie concetratia 4 la suta


Răspuns :

EX. 1 1. Md= 12g C= 3% Ms = (12x100):3 Ms= 400 EX. 2 Ms= 200g C= 4% Md = (200x4):100 Md = 8 g sare
1)c=3%
md=12g
ms=?
c=[tex] \frac{md}{ms} [/tex]×100⇒3=[tex] \frac{12g}{ms} [/tex]×100⇒3ms=1200g⇒ms=400g
2)c=4%
ms=200g
md=?
c=[tex] \frac{md}{ms} [/tex]×100⇒4=[tex] \frac{md}{200g} [/tex]×100=[tex] \frac{md}{2g} [/tex]⇒md=4×2g=8g