Molalnost

Star dust's picture

Koliko je grama NaOH i vode potrebno za pripremanje 330g rastvora molalnosti 2,5 mol/kg?

milicaradenkovic's picture

b=2.5 mol/kg

b=n/m(vode)

2.5=ms/Mr*(mr-ms)

2.5=ms/0.04*(0.330-ms)

0.1*(0.330-ms)=ms

0.0330=1.1*ms

ms=0.033/1.1=0.03 kg=30 g NaOH

m(vode)=mr-ms=330-30=300 g