Question

repede va rog, toate cele 3 exercitii

Answer 1

Răspuns:

Explicație:

1.

md= 45g NaCl

mapa= 155g

c=?

c= md.100 : ms

ms= md + mapa

ms= 45 + 155= 200g sol. de NaCl

c= 45 .100 : 200=22,5%

2.

120g NaOH

Vs= 1500mL= 1,5 L

cm=?

cm= n : Vs

n= m : M

MNaOH= 23 + 16 +1=40----> 40g/moli

nNaOH= 120g : 40g/moli= 3moli

cm= 3moli : 1,5 L= 2 moli /L

3.

cm= 4moli /L

196g H2SO4

Vs H2SO4

n= m : M

M H2SO4= 2 + 32 + 4.16=98----> 98g/moli

n= 196g : 98g/moli= 2moli H2SO4

cm = n : Vs

Vs= n : cm

Vs= 2moli : 4moli /L = 0,5 L sol. H2SO4