Question

Se amesteca 300 g solutie NaOH de concentratie 10% , 20 g NaOH solid si 180 g apa. Ce concentratie are solutia obtinuta ?​

Answer 1

Răspuns:

SOLUTIA 1

ms= 300g

c1=10%

c1= md1x100/ms---> md1= 10x300/100g=30gNaOH

SOLUTIA 2

c=md2x100/ms2    unde    md2= md1+m,adaugat= 30g+20g=>50g

                                          ms2= ms1+m,adaugat+ m,apa=          300+20g+180g=500g

c2= 50x100/500=10%

Explicație: