Zadatak-stehiometrija

Submitted by Azra on Thu, 02/27/2014 - 10:37

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Smjesa NaOH i KOH mase 13,6g u reakciji sa HCl daje 19,5g NaCl i KCl. Koliko ima g NaOH a koliko KOH u toj smjesi?

Hvala unaprijed.

milicaradenkovic - Thu, 02/27/2014 - 11:07

m(smese)=m(NaOH)+m(KOH)

NaOH+HCl------------------->NaCl+H2O

KOH+HCl---------------------->KCl+H2O

m1=m(NaCl)+m(KCl)

n(NaOH)=n(NaCl)

n(KOH)=n(KCl)

19.15=n(NaOH)*Mr(NaCl)+n(KOH)*Mr(KCl)

m(KOH)=13.6-m(NaOH)

19.15=m(NaOH)*Mr(NaCl)/Mr(NaOH)+m(KOH)*Mr(KCl)/Mr(KOH)

19.15=m(NaOH)*58.5/40+(13.6-m(NaOH))*74.5/56

19.15=1.4625*m(NaOH)+18.09-1.33*m(NaOH)

1.06=0.1325*m(NaOH)

m(NaOH)=1.06/0.1325=8 g

m(KOH)=13.6-m(NaOH)=13.6-8=5.6 g

Masa NaCl i KCl nije 19.5 nego 19.15 g

Azra - Thu, 02/27/2014 - 22:01

Aha, hvala jos jednom! :)

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