Question

Sn(OH)2 se obtine prin adaugarea unei solutii de NaOH peste solutie de SnCl2.Scrie ecuatiareactiei chimice care are loc si calculeaza masa de Sn(OH)2 care se poate obtine din 200 g solutie de SnCl2 de concentratie 38% si 100 g solutie NaOH de concentratie 20%; masa de Sn(OH)2 este?

Answer 1

MSn(OH)2=ASn+2(AO+AH)=119+2(16+1)=153g/mol
MSnCl2=ASn+2ACl=119+2*35,5=190g/mol
MNaOH=ANa+AO+AH=23+16+1=40g/mol
C=md/ms*100=>md=C*ms/100=38*200/100=76g SnCl2
n=m/M=76/190=0,4 moli SnCl2
C=md/ms*100=>md=C*ms/100=20*100/100=20g NaOH
n=m/M=20/40=0,5 moli NaOH
NaOH in exces.. 2NaOH + SnCl2 => Sn(OH)2 + 2NaCl
2*40g NaOH....190g SnCl2....153g Sn(OH)2
xg NaOH.......76g SnCl2....yg Sn(OH)2
x=80*76/190=32g NaOH
m exces NaOH = 32-20=12g
y=153*76/190=Calculează !!!