Question

Calculati concentratia molara a solutiei obtinute prin amestecarea a 200 g sol NaOH c=20% (densitate=1,225g/ml) cu 36,74 ml de apa

Answer 1

Răspuns:

se stie   c,m= niu/V

c=mdx100/ms

md= 20x200/100g= 40gNaOH

miu,NaOH=40g/mol------> niu=m/miu=40/40mol=1mol

V= Vs+ V apa

ro=m/v---> v=m/ro=200g/1,225g/ml=163,26ml

V= 163,26ml+36,74ml=200ml= 0,2l

c,m=niu/V= 1/0,2mol/l=5mol/l

Explicație: