(1)① ion representation: in the upper right corner of the symbol of the element representing the ion, mark the number of positive and negative charges carried by the ion, with the number before and the symbol after. When carrying 1 charge, the symbol of 1 calcium ion should be omitted: Ca2+;

(2) The two symbols of oxygen atom are the number 2 added before the symbol of oxygen element, and the symbol is 2O;

③ According to the writing method of chemical formula, the chemical formula of alcohol is C2H5OH; ;

There is a proton in the nucleus of a hydrogen atom, and there is an electron layer outside the nucleus, and there is an electron on this layer. The schematic diagram of atomic structure is:

⑤ The oxide with the mass ratio of hydrogen to oxygen of 1: 16 is water, and the chemical formula is H2O；; ;

(2)① The reduction of copper oxide by carbon monoxide is a non-displacement reaction with metal formation, and the reaction equation is: CO+CuO△. Copper+carbon dioxide;

② Carbon dioxide reacts with water to produce carbonic acid, which belongs to the compound reaction of two oxides. The reaction equation is: CO2+H2O-H2CO3.

So the answer is: (1) ① Ca2+; ②2O； ③C2 H5 oh； ④ Figure ⑤(2)①CO+CuO△. Copper+carbon dioxide; ②CO2+H2O═H2CO3.