(2) Iron reacts with copper ions in the solution to smelt copper by wet process. The chemical equation of the reaction is: Cu2++Fe═Fe2++Cu, so the answer is: HgS△. Mercury+sulfur;
(3) When 8kg copper is produced, the mass of iron involved in the reaction is X. 。
Iron+copper sulfate = copper+ferrous sulfate
56 64
8 kg
Then: 56X? = 648 kg, x = 7 kg
When 8kg copper is produced, the weight of iron kettle increases by 1kg, and the initial weight of iron kettle is11.5 kg-1kg =10.5 kg.
So the answer is:10.5;
(4)① According to the information in the figure, B is iron oxide, L is hydrogen, F is water, E is carbon dioxide, D is copper oxide and A is basic copper carbonate, then B should contain metal element Fe, and the electron type of gas L is H: H,
So the answer is: Fe; H:H；
② Chemical equation△ for decomposing basic copper carbonate by heating Cu2(OH)2CO3. 2CuO+CO2↑+H2O, so the answer is: Cu2(OH)2CO3△. 2CuO+CO2↑+H2O。