Question

ce cantitate de solutie de sare de bucatarie trebuie sa se adauge la 200 grame solutie de concentratie 10 % pentru ca solutia sa-si bubleze concentratia

Answer 1

cinitiala=mdinitiala/msinitiala x 100

mdinitiala=200x10/100=20gNaCl

cfinala=mdfinala/msfinala x 100

mdfinala=mdinitiala+mdadaugata(A)

msfinala=msinitiala+mdadaugata(A)

20=20+A/200+A x 100

20x(200+A)=(20+A)x100

Se impart ambii termeni prin 20, stanga si dreapta.

200+A=(20+A)x5

200+A=100+5A

5A-A=200-100

4A=100

A=mdadaugata=100/4=25gNaCl