Răspuns:
Al2O3
r.at. Al:O=2:3
r.m Al:O=54:48=9:8
MAl2O3=2×27+3×16=102g/mol
102g Al2O3.....54gAl.......48gO
100gAl2O3.......xgAl........ygO
x=100×24/102=calculează
y=100×48/102=calculeaza
Na2SO4
r.at.Na:S:O=2:1:4
r.m. Na:S:O=46:32:64
MNa2SO4=2×23+32+4×16=142g/mol
142gNa2SO4.....46gNa......32gS..........64gO
100gNa2SO4......xgNa..........ygS..........zgO
x=100×46/142=calculeaza
y=100×32/142=calculeaza
z=100×64/142=calculeaza
K2CO3
r. at. K:C:O=2:1:3
r.m K:C:O=39:12:48
MK2CO3=2×39+12+3×16=138g/mol
138gK2CO3...........78gK......12gC........48gO
100gK2CO3..........xgK.........ygC.........zgO
x=100×78/138=calculeaza
y=100×12/138=calculeazaâ
z=100×48/138=calculeaza
Ca(NO3)2
r.at.Ca:N:O=1:2:6
r.m. Ca:N:O=40:28:96
MCa(NO3)2=40+2×14+6×16=164g/mol
164gCa(NO3)2.........40gCa...........28gN..........96gO
100gCa(NO3)2...........xgCa............ygN............zgO
x=100×40/164=calculeaza
y=100×28/164=calculeaza
z=100×96/164=calculeaza
Explicație:
