Question

Peste 475 ml apa distilata se adauta legt 25 ml acid sulfuric cu 20% SO3 ( densitatea = 1,89 g / ml ) Calculeaza :
a) Concentratia molara a solutiei de H2SO4 obtinuta;
b) Concentratia procentuala a aceleiasi solutii;
c) Masa de solutiei de amoniac 15% necesara neutralizarii solutiei de H2SO4.

Answer 1

d=ms/Vs => ms=d*Vs=1,89*25=47,25g
20% din 47,25=20*47,25/100=9,45g SO3
apa are d=1g/ml => avem 475g apa
SO3-ul reactioneaza cu o parte din apa formand acid
80g.....18g........98g
SO3 + H2O -> H2SO4
9,45g..2,12625g..11,57625g
md=47,25-9,45+11,57625=49,37625g acid
ms=475g solutie
c=md*100/ms=10,395%
2*17g......98g
2NH3 + H2SO4 -> (NH4)2SO4
17,0305....49,37625g
15/100=17,0305/ms => msNH3=114,203571g solutie NH3
Vsacid=500ml=0,5L
nacid=49,37625/98=0,5moli
Cm=n/Vs=0,5moli/0,5L=1M