Объяснение:
1) Mr(Si3H8) = 28*3 + 1*8 =92
W(Si) = Ar(Si) *n / Mr(Si3H8) *100% = 28*3 / 92 *100% =91%
W(H) = Ar(H) *n / Mr(Si3H8) *100% = 1*8 / 92 *100% = 9%
2) Mr(CaSiO3) = 40 + 28+16*3 =116
W(Ca) = Ar(Ca) *n / Mr(CaSiO3) *100% = 40*1 / 116 *100% =34%
W(Si) = Ar(Si) *n / Mr(CaSiO3) *100% = 28*1 / 116 *100% =24%
W(O) = Ar(O) *n / Mr(CaSiO3) *100% =42%
3) Mr(Zn(NO3)2) = 65+ 14*2 + 16*6 =189
W(Zn) = Ar(Zn) *n / Mr(Zn(NO3)2 *100% = 65*1 / 189 *100% =34%
W(N) = Ar(N) *n / Mr(Zn(NO3)2 *100% = 14*2 / 189 *100% =15%
W(O) = Ar(O) *n / Mr(Zn(NO3)2 *100% = 16*6 / 189 *100% =51%
4Al + 3O2 =2 Al2O3
108г 204 х= 54*204/108=102г
54г х
M( Al)= 27г/моль
m( Al )= 108г
M( Al2O3)= 102г/моль
m( Al2O3)=204г