Răspuns:
MPb(NO3)2=207+2×14+6×16=331g/mol
331gPb(NO3)2..........................207gPb................28gN...............96gO
100gPb(NO3)2................................xgPb.................ygN................zgO
x=100×207/331=calculeaza
y=100×28/331=calculeaza
z=100×96/331=calculeaza
Explicație: