Ответ:

Объяснение:

1) Mr(Rb3PO4) =85*3 + 31 + 16*4 =350

W(Rb) = Ar(Rb) *n / Mr(Rb3PO4)  *100% = 85*3 / 350  *100% =50%

2) Mr(Sr(NO3)2) = 88 + 14*2 + 16*6 =212

W(Sr) = Ar(Sr) *n / Mr(Sr(NO3)2)  *100% = 88 *1 / 212  *100% =41,5%

3) Mr(In(OH)3) = 115 + 16*3 + 1*3 =166

W(In) = Ar(In) *n / Mr(In(OH)3)  *100% = 115 *1 / 166  *100% =69%

4) Mr(Al2(SiO3)3) = 27*2 + 28 *3 + 16*9 = 282

W(Si) = Ar(Si) *n / Mr(Al2(SiO3)3)  *100% = 28*3 / 282  *100% =30%

5) Mr(Sb2O5) = 122 *2 + 16*5 =324

W(Sb) = Ar(Sb)  *n / Mr(Sb2O5)  *100% = 122 *2 / 324  *100% =75%

6) Mr(H2Se) = 1*2 + 79 = 81

W(Se) = Ar(Se) *n / Mr(H2Se)  *100% = 79 * 1 / 81  *100% =97,5 %

7) Mr(Br2O7) = 80 *2 + 16*7 =272

W(Br) = Ar(Br)  *n / Mr(Br2O7)  *100% = 80*2 / 272  *100% =59%