Is the law of chemical energy and electric energy conversion a typical problem with equation?

Is the law of chemical energy and electric energy conversion a typical problem with equation?

dry battery
Negative electrode (zinc sheet): Zn = Zn2 + + 2e-
Positive electrode (carbon rod): 2mno2 + 2nh4 + + 2E - = Mn2O3 + 2nh3 + H2O
Total reaction: Zn + 2mno2 + 2nh4 + = 2zn2 + + Mn2O3 + 2nh3 + H2O

After working for a period of time, the mass of copper sheet increases by 12.8g, and the solution just becomes colorless. Assuming that there is no copper precipitation on the zinc sheet, we try to calculate: (1) how many grams does the mass of zinc sheet decrease after corrosion? (2) How many electrons flow through the external circuit? (3) What is the mass concentration of the original copper sulfate solution?

The results show that the electrode reaction is zn-2e - = Zn2 +; when copper is used as the cathode, the copper ions in the solution get electrons to form copper, and the reduction reaction takes place. The electrode reaction is Cu2 + + 2E - = Cu, the mass of copper sheet increases by 12.8g, and the solution just turns colorless