Răspuns:
2.
a) F
b) A
c) F
d) A
e) F
f) F
3.
H₃PO₃
raport atomic=H:P:O=3:1:3
raport de masa=H:P:O=3:31:48
compozitie procentuala
MH₃PO₃=3×1+31+3×16=82g/mol
82g H₃PO₃.................3gH...............31gP.............48gO
100g H₃PO₃................xgH..................ygP.................zgO
x=100×3/82=calculeaza
y=100×31/82=calculeaza
z=100×48/82= calculeaza
4.
MAl=27g/mol
n=m/M=N / Na
n=1,8/27=0.06moli Al
N = n x Na = 0.06×6,023 x 10²³ atomi= calculeaza
Explicație:
Na =6,023 x 10²³ atomi
