Final answer:
In the reactions CuSO4 + Zn and Cu + 2AgNO3, zinc and copper are the substances oxidized, while copper(II) ions and silver ions are reduced. Zinc and copper act as reducing agents, and copper(II) ions and silver ions serve as oxidizing agents.
Step-by-step explanation:
In the reaction CuSO4 + Zn = Cu + ZnSO4, zinc (Zn) is oxidized because it loses electrons and turns into Zn2+ ions. Copper(II) sulfate (CuSO4) acts as the oxidizing agent because it causes zinc to lose electrons. The substance reduced is copper(II) ions (Cu2+) as they gain electrons to form copper (Cu) metal. Thus, copper(II) ions are the reducing agent.
For the reaction Cu + 2AgNO3 = Cu(NO3)2 + 2Ag, copper (Cu) is the substance oxidized, as it loses electrons to form Cu2+ ions. Silver ions (Ag+) are reduced to form silver (Ag) metal. Consequently, copper (Cu) acts as the reducing agent and the silver ions (Ag+) function as the oxidizing agent.