an industrial chemist is studying a sample of an unknown metal. describe two ways he could change the metal…

Brief Explanations:

Physical changes do not alter the substance's chemical composition. Chemical changes result in new substances. For physical changes, we can consider changes in shape and state. For chemical changes, reactions with acids and oxygen are common.

• Physical changes:
  • Shape - related: Hammering the metal to change its shape. This just deforms the metal without changing its chemical makeup.
  • State - related: Melting the metal to change its state from solid to liquid. It's a phase change and the metal's chemical identity remains the same.
• Chemical changes:
  • Reaction with acid: Reacting the metal with a dilute acid like hydrochloric acid. Different metals react differently with acids, some producing hydrogen gas. For example, zinc reacts with hydrochloric acid to form zinc chloride and hydrogen gas ($Zn + 2HCl\rightarrow ZnCl_2 + H_2\uparrow$).
  • Oxidation: Exposing the metal to air (oxygen) to see if it corrodes or forms an oxide layer. For instance, iron reacts with oxygen and water to form rust (iron(III) oxide - hydrate).

Answer:

• Physical changes: Hammer the metal to change its shape; melt the metal to change its state.
• Chemical changes: React the metal with a dilute acid; expose the metal to air to check for oxidation.