Question

Peste 200g solutie de clorura de sodiu de concentratie 10% se adauga 400g solutie de clorura de sodiu de concentratie 20% si 400g apa. Care va fi concentratia procentuala a solutiei finale?

Answer 1

ms1 = 200 g , c1 = 10%

din c = mdx100/ms

=> md1 = ms1xc1/100 = 200x10/100

= 20 g

ms2 = 400 g , c2 = 20%

din c = mdx100/ms

=> md2 = ms2xc2/100 = 400x20/100

= 80 g

md1+md2 = 20+80 = 100 g

ms1+ms2+m.apa = 200+400+400 = 1000 g sol. finala

c.final = md.totx100/ms.final

= 100x100/1000 = 10%