I don't understand how to do the equations when some of the elements are in parenthses


BA(OH)2 + H3PO4 --> BA3(PO4)2 +H2O


Fe(OH)3 --> Fe2O3 + H2O


Zn(OH)2 + H3PO4 --> Zn3(PO4)2 + H2O


Au + NaCN + H2O + O2 --> NaOH + NaAu(CN)2

It's like maths you multiply the brackets by the nuber next to it. So (PO4)2 would mean the compound contains two phosphate (PO4) groups. Are you all right with the rest? If you just write out all the atoms and cross them off as they balance on each side you can't really go wrong.