Question

Se introduc 20 grame zinc impur intr-un pahar in care se gaseste solutie de acid clorhidric si se degaja 0,5 grame hidrogen.
Calculati puritatea zincului si masa solutiei de acid clorhidric 9%.

Answer 1

Zn + 2HCl = ZnCl2 + H2

MZn=65g/mol

MH2=2AH=2*1=2g/mol

MHCl=AH+ACl=1+35,5=36,5g/mol

65g Zn..................................2g H2
x=16,25g............................0,5g H2

puritatea = mpur/m impur/100=16,25/20*100=81,25%

2*36,5 HCl...............................2g H2
x=.............................................0,5g

x=0,5*73/2=18,25g HCl (md)

Cp=md/ms*100=>ms=md*100/Cp=1825/9= Calculeaza !