Question

Salut! Rog rezolvarea problemei 5.
Mulțumesc.

Answer 1

5. a) C = md/ms ×100 => md = C×ms/100 = 5×30/100 = 1,5g KOH

Cf = md+x/ms+x×100

10 = (1,5+x)/(30+x)×100

10(30+x) = 100(1,5+x)
300+10x = 150+100x
150=90x
x = 1,666g KOH

V: md final = 1,5+1,666 = 3,16g KOH
md final = 30+1,666 = 31,66g sol. KOH

Cf = 3,16/31,66×100 = 10%

b) ms = md+mH2O => mH2O = ms-md = 30-1,5 = 28,5g H2O

C×mH2O = md(100-C)

mH2O = md(100-C)/C = 1,5(100-10)/10 = 13,5g

mH2O evaporata = 28,5-13,5 = 15g