Question

Peste 120 g solutie 20% hidroxid de sodiu se adauga 30 g de solvat. Ce concentratie procentuala are solutia finala ? Va rog din suflet sa ma ajutati ! Dau coroana ! Multumesc anticipat !

Answer 1

Avem:

ms1=120g

c1=20%

md2=md1+30g

c1/100=md1/ms1

20/100=md1/120

1/5=md1/120

md1=120/5

md1=24g

md2=24+30

md2=54g

ms2=ms1+(md2-md1)

ms2=120+30=150g

Deci c2/100=md2/ms2

c2/100=54/150

c2=5400/150

c2=36%

Sper sa intelegi! :)