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2 grame de alaun se dizolva in 100g apa. Ce concentratie are solutia obtinuta?

Răspuns :

concentratia este 2/100=2%
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Alaunul are formula KAl(SO4)2•12H2O
M KAl(SO4)2•12H2O= 39+27+64+128+12×18=474 g/mol
474g KAl(SO4)2•12H2O....258gKAl(SO4)2
2g KAl(SO4)2•12H2O....x g KAl(SO4)2
x=1,088g subst. anhidra (md)
ms=m alaun+m H2O=2+100=102g
c=md/ms×100= 1,088/102×100=1.066%