1.Cu(OH)2 este substanta.
Cu:O:H=(1*64):(2*16):(2*1)=64:32:2=32:16:1
32:16:1 procentul masic
MCu(OH)2= ACu + 2*AO + 2*AH= 64+32+2= 98 g/mol
MCu=64g/mol
1mol Cu(OH)2 = 98g/mol
%m Cu= (64g/98g) *100
%m Cu= 65.3061224489796
2.
http://www.scrigroup.com/files/chimie/625_poze/image027.jpg