M : 1s²2s²2p⁶3s²3p⁶4s²3d⁷ Z = 27 M = Co
b) 9,033ₓ10²³/(6,022ₓ10²³) = 1,5 moli protoni
1mol Co ( 59 g) .... contine..... 27 moli protoni
x ............................................ 1,5 x = 59ₓ1,5/27 = 3,27 g Co
c) cristalohidrat : CoCl2ₓ6H2O M = 130+ 108 = 238 g/mol n = 0,1 moli
ms = 176,2 + 23,8 = 200g md = 0,1ₓ130 = 13g
c = 1300/200 = 6,5%