Question

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

Answer 1

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

Answer 2

1)c=3%
md=12g
ms=?
c=$\frac{md}{ms}$×100⇒3=$\frac{12g}{ms}$×100⇒3ms=1200g⇒ms=400g
2)c=4%
ms=200g
md=?
c=$\frac{md}{ms}$×100⇒4=$\frac{md}{200g}$×100=$\frac{md}{2g}$⇒md=4×2g=8g