Răspuns:
Explicație:
1.
MCa(NO3)2 = ACa + 2. AN + 6 .AO
=40 + 2. 14 + 6.16
=40 + 28 + 96
=164 --------> 164 g/moli
MNa3PO4= 3.23 + 31 + 4.16=164--------> 164g/moli
MCuSO4 . 5 H2O= 64 + 32 + 4.16 + 5 . 18
=160 + 90
=250 ---------> 250g/moli
2.
FeCl3
N2O
Na2CO3
Al(OH)3
CuSO4
3.
Mg3(PO4)2
r.a.= 3 : 2 : 8
r.m.= 3 . 24 : 2 . 31 : 8 . 16
=72 : 62 : 128 se simplif. cu 2
=36 : 31 : 64
==>comp. proc . prin masa molara
M = 72 + 62 + 128 =262 ------> 262 g/moli
262 g Mg3(PO4)2------72g Mg------62 g P-------128 g O
100g---------------------------x------------------y---------------z
x= 100 . 72 : 262 = 27,48% Mg
y=100 .62 : 262 = 23,67 %P
z= 100 . 128 : 262 = 48,85%O
