Tentukan Mr Dari senyawa berikut! a. Fe (OH)2 b. C2H5OH

a) Ar ; Fe = 56, O = 16, H = 1
Mr Fe(OH)2 = 56 + 2.16 + 2.1 =56 + 32 + 2 = 90

b) Ar ; C = 12, H = 1, O = 16
Mr C2H5OH = 2.12 + 6.1 + 16 = 24 + 6 + 16 = 46