Question

Calculati concentratia procentuala si molara a solutiei NaOH obtinuta prin amestecarea a 500 ml solutie NaOH dublu molara cu densitatea(q) =1,05 g\ml cu 300 ml apa distilata.

Answer 1

Cm1=n/Vs

n=CmxVs

n=2x0,5

n=1 mol NaOH

n=md/M

1=md/40

md=40 g NaOH

sau Cm=cxρs/MX100

2=cx1050/4000

c=7,619%-initial

ρs=ms/Vs

ms=ρsxVs

ms=1,05x500

ms=525 g solutie NaOH

mapa=Vapa=300mL=0,3L

Vfinal=500+300=800mL

ms final=525+300=825 g

cfinal=40x100/825

cfinal=4,84%

Cm=1/0,8

Cm=1,25 molar