Question

1)Peste 400 g solutie de concentratie 40% se aduga 500 g apa . Determina concentratia solutiei finale
2)600 g solutie apa -sare de bucatarie cu concentratia procentuala 20% este incalzita . Se evapora200 g apa. Determina concentratia solutiei obtinute.. Varog descrieti si cum ati facut.

Answer 1

1)

ms = 400g, c% = 40%

=> md = msxc%/100 = 400x40/100 = 160 g

ms.final = ms+m.apa = 400+500 = 900 g

c%.final = 160x100/900 = 17,78%

2)

ms = 600g, c% = 20%

=> md = msxc%/100 = 600x20/100

= 120 g

ms.final = ms-m.apa.evaporata = 600-200 = 400g

c%.final = 120x100/400 = 30%