K2CO3+CaCl2=CaCO3(沉淀)+2KCl
BaCl2+Na2SO4=BaSO4(沉淀)+2NaCl
CuSO4+Ba(OH)2=BaSO4(沉淀)+Cu(OH)2(沉淀)
CuSO4+Zn=ZnSO4+Cu