Срочно помогите !!!!!!
Ar = Mr Ar(Au) = 197 Ar(Mn) = 55 Ar(Al) = 27 Mr(Al2O3) = 2Ar(Al) + 3Ar(O) = 2*27 + 3*16 = 102 Mr(NaOH) = Ar(Na) + Ar(O) + Ar(H) = 23 + 16 + 1 = 40 Mr(CH4) = Ar(C) + 4Ar(H) = 12 + 4*1 = 16