Deci.
Respect Bahoi de la Constanta.
Reactia:
[tex]Pb( NO_{3} ) _{2} +Zn->Zn( NO_{3}) _{2} + Pb[/tex]
[tex]1ml=1 cm^{3} =>200ml=200 cm^{3} ( volumul )[/tex]
[tex]ro= \frac{ms}{vs} [/tex] ( masa ( m ) si volumul ( V ) )
Inlocuim:
[tex] \frac{1.2}{1} = \frac{ms}{200} => ms=200*1.2=240 g[/tex]
[tex] \frac{c}{100}= \frac{md}{ms }=> \frac{10}{100}= \frac{md}{240} => md= \frac{240*10}{100}=24g Pb( NO_{3}) _{2} [/tex]
Facem masele moleculare:
Masa la [tex]Pb( NO_{3}) _{2} = 207 + 28 + 96 =331g[/tex]
Masa la Pb = 207 g
Acum:
Daca din 331 g [tex]Pb( NO_{3}) _{2} => 207 g Pb[/tex]
Atunci din 24 g [tex]Pb( NO_{3}) _{2} => x g Pb
x = [tex] \frac{24*207}{331} = 15 [/tex] grame Pb
1 mol Pb .......... 207 g
a moli Pb ..........15 g
a = [tex] \frac{15*1}{207} = 0.07[/tex] moli
Nuj daca-i bine.
