Question

Se considera acidul A care are compozitia procentuala de masa: 0,995% H; 35,323% Cl; 63,681% O si 6 atomi in molecula.
a) Indentificati acidul A
b) Calculati masa de acid A care contine de 3 ori mai mult clor decat 73 g de HCl.
c) Calculati numarul de moli de acid A care se afla in 402 g de solutie de concentratie 10%.

Answer 1

a) H: 0,995/1 = 0,995 : 0,995 => 1 atom H
Cl : 35,323/35,5 = 1  : 0,995 => 1 atom Cl
O: 63,681 /16 = 3,98 : 0,995 => 4 atomi O

F.B => HClO₄ - acid percloric

b) 1 mol HCl ...........35,5g Cl
3 moli......................106,5g Cl

MHClO₄ = 100,5g/mol

m HClO₄ = 3*100,5 = 301,5g HClO₄

c) C = md/ms*100 = > md = C*ms/100 = 10*402/100 = 40,2g HClO₄

n = m/M = 40,2/100,5 = 0,4 moli HClO₄