Question

Ce cantitate de sulfat de potasiu solid se adauga la 650ml solutie 3% K2SO4 cu densitatea 1.05g/ml pentru a prepara o solutie saturata la 15grade, stiind ca solubilitatea K2SO4 la aceasta temperatura este 10g/100g H20?

Answer 1

S¹⁵ = 10g/100g apa

=> ms = 100+10 = 110g

c%final = md.finalx100/ms = 10x100/100 = 10%

Vs= 650 mL , ro=p = 1,05 g/mL

p = ms/Vs => ms = pxVs = 1,05x650 = 682,5 g

c1 = md1x100/ms1 => md1 = ms1xc1/100

= 682,5x3/100 = 20,475 g

md.final = md1 + md.adaugat(a) = 20,475 + a

ms.final = ms1 + a = 682,5 + a

=> 10 = (20,475+a)100/(682,5+a)

=> a = 477,75/9 = 53,083 g K2SO4 adaugat

facem proba:

md.final = 20,475 + 53,083 = 73,5583 g

ms.final = 682,5 + 53,083 = 735,583 g

=> c%final = 73,5583x100/735,583 = 10%, deci verifica calculele de mai sus