pH

Submitted by haris100 on Wed, 06/14/2017 - 18:51
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Ako pomijesamo 100cm3 rastvora ciji je pOH 2 sa 900 cm3 rastvora ciji je pH 7, dobicemo rastvor ciji je pH?

Marija 96's picture

Marija 96 - Thu, 06/15/2017 - 19:16

Meni ispada pH=11

Da li imaš rješenje?

haris100's picture

haris100 - Thu, 06/15/2017 - 21:47

Jest 11

Marija 96's picture

Marija 96 - Fri, 06/16/2017 - 20:06

Sad cu naci prvo 

n(OH-)=V*c=100cm*0,01mol/dm3 =0,1dm3*0,01mol/dm3=0,001mol

n(H+)=V*c=900cm3*0,0000001mol/dm3=0,9*0,0000001mol/dm3=0,00000009mol

vidimo da su u visku OH- joni i to za

nv=0,001-0,00000009mol=0,00099991mol

[OH-]=nviska/Vu=0,00099991mol/1dm3=0,00099991mol/dm3

pOH=-log(9,9991*10-4 )=4-log9,9991=4-0,99..=3,00

pH=14-3,0..=11

haris100's picture

haris100 - Sun, 06/18/2017 - 22:12

Hvala ti