You are given a hammer, a battery, a bulb, wires and a switch. (a) How could you use them to distinguish between samples of metals and non- metals? (b) Assess the usefulness of these tests in distinguishing between metals and non-metals. What are amphoteric oxides? Give two examples of amphoteric oxides.

To distinguish between metals and non-metals, we can use a simple electrical circuit with a battery, bulb, wires, and a switch. First, create the circuit by connecting the components as follows: Attach one end of the wire to the positive terminal of the battery and the other end to one terminal of the switch. Then, connect another wire from the switch to one terminal of the bulb. Finally, use the remaining wire to link the bulb’s other terminal to the battery’s negative terminal. The sample should be inserted between an open end of the wire and the terminal of the battery. When you turn on the switch, observe if the bulb lights up. If it does, the sample is a metal because it conducts electricity. If it doesn't light up, the sample is a non-metal, indicating poor conductivity.

The malleability test helps identify metals based on their ability to deform under pressure. Gently tap the sample with a hammer. Metals are malleable, meaning they will change shape or flatten without breaking when struck. This characteristic allows them to be formed into sheets and shapes easily. In contrast, non-metals are usually brittle. When you tap a non-metal sample with a hammer, it is likely to break or shatter rather than deform. By observing the sample's reaction to the hammer tap, you can classify it as either a metal (malleable) or a non-metal (brittle).

Amphoteric oxides have the unique ability to react with both acids and bases. This trait allows them to exhibit both acidic and basic properties, leading to the formation of salt and water. Two prime examples of amphoteric oxides are zinc oxide (ZnO) and aluminum oxide (Al₂O₃). For instance, ZnO reacts with hydrochloric acid (an acid) and sodium hydroxide (a base) as follows:
- Reaction with HCl (Acid): Equation: ZnO + 2HCl → ZnCl₂ + H₂O
- Reaction with NaOH (Base): Equation: ZnO + 2NaOH + H₂O → Na₂[Zn(OH)₄]
Similarly, Al₂O₃ reacts with acids and bases: - Reaction with HCl (Acid): Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O - Reaction with NaOH (Base):
Al₂O₃ + 2NaOH + 3H₂O → 2Na[Al(OH)₄]
Understanding these reactions helps in identifying amphoteric oxides and their behavior in different chemical environments.