Mr(N2) = 2Ar(N) = 2 * 14 = 28
Mr(CH4) = Ar(C) + 4Ar(H) = 12 + 4 * 1 = 16
Mr(SO2) = Ar(S) + 2Ar(O) = 32 + 2 * 16 = 64
Mr(H2SO4) = 2Ar(H) + Ar(S) + 4Ar(O) = 2 * 1 + 32 + 4 * 16 = 98
Mr((NH4)2SO4) = 2Ar(N) + 8Ar(H) + Ar(S) + 4Ar(O) = 2 * 14 + 8 * 1 + 32 + 4 * 16 = 132
Mr(N2) = 2Ar(N) = 2 * 14 = 28
Mr(CH4) = Ar(C) + 4Ar(H) = 12 + 4 * 1 = 16
Mr(SO2) = Ar(S) + 2Ar(O) = 32 + 2 * 16 = 64
Mr(H2SO4) = 2Ar(H) + Ar(S) + 4Ar(O) = 2 * 1 + 32 + 4 * 16 = 98
Mr((NH4)2SO4) = 2Ar(N) + 8Ar(H) + Ar(S) + 4Ar(O) = 2 * 14 + 8 * 1 + 32 + 4 * 16 = 132