Ответ:

Объяснение:

Mr(N2) = Ar(N) * 2 = 14 * 2 = 28

Mr(SO2) = Ar(S) + Ar(O) * 2 = 32 + 16 * 2 = 64

Mr(NaCl) = Ar(Na) + Ar(Cl) = 23 + 35,5 = 58,5

Mr(SO3) = Ar(S) + Ar(O) * 3 = 32 + 16 * 3 = 80

Mr(B2O3) =  Ar (B) * 2 + Ar (O) * 3 = 11 * 2 + 16 * 3 = 70

Mr(Mn2O7) = Ar(Mn) * 2 + Ar(O) * 7 = 55 * 2 + 16 * 7 = 222

Mr(H3PO4) = Ar(H) * 3 + Ar(P) + Ar(O) * 4 = 1 * 3 + 31 + 16 * 4 = 98

Mr(Na2CO3) =  Ar(Na)*2 + Ar(C) + Ar(O)*3 = 23 * 2 + 12 + 16 * 3 = 106

Mr(Al(OH)3 = Аr(Al) + 3*Аr(О) + 3*Аr(Н) = 27 + 3*16 + 3*1 = 27 + 48 + 3 = 78

Mr(Al2(SO4)3 = 2*Ar(Al)+3*Ar(S)+12*Ar(O)= 27 * 2 + 3 * 32 + 12 * 16 = 342