Mr(CO2) = Ar(C) + 2Ar(O) = 12 + 16 * 2 = 44
Mr(C12H22O11) = 12Ar(C) + 22Ar(H) + 11Ar(O) = 12 * 12 + 22 * 1 + 11 * 16 = 342
Mr(NaHCO3) = Ar(Na) + Ar(H) + Ar(C) + 3Ar(O) = 23 + 1 + 12 + 3 * 16 = 84
Mr(CH3COOH) = 2Ar(C) + 4Ar(H) + 2Ar(O) = 2 * 12 + 4 * 1 + 2 * 16 = 60
Mr(NaCl) = Ar(Na) + Ar(Cl) = 23 + 35.5 = 58.5