In this chemical reaction, there is transfer of electrons from zinc (Zn) to copper (Cu). Zinc change oxidation number from 0 to +2 (lost electrons) and copper change oxidation number from +2 to 0 (gain electrons).
Oxidation half reaction: Zn⁰ → Zn²⁺ + 2e⁻.
Reduction half reaction: Cu²⁺ + 2e⁻ → Cu⁰.
In other chemical reactions, there is no change of oxidation number of elements.
it will be hard, but you can do it. Just study given the materials for the course. Understand enthalpy and entropy, and various types of bonding and you'll be fine.
