Test la chimie varianta II,foto 2

Răspuns:
3. a) A
b) A
c) F
4.
acid : H2CO3 acid carbonic
baza: NaOH hidroxid de sodiu
sare: Na2CO3 carbonat de sodiu
5.
MNaOH=23+16+1=40g.mol
MNa2SO4=2x23+32+4x16=142g/mol
2x40.................................142g
2NaOH + H2SO4 → Na2SO4 + H2O
400g.................................xg
x=400x142/2x40=calculeaza
Explicație: