Why do iron objects rust, but gold does not?
Iron is reactive and combines with oxygen and water to form rust. Gold is an unreactive metal, and it does not react with oxygen, even at high temperatures.
What is electrolysis and how is it used to extract metals?
Electrolysis is a process that uses electric current to break down compounds into their elements. It is used to extract metals like sodium and aluminum from their compounds.
Why are gold and platinum found in their free state?
Gold and platinum are low in the reactivity series, meaning they do not easily form compounds with other elements and can exist in nature in their pure form.
What is the difference between a mineral and an ore?
A mineral is a naturally occurring substance, while an ore is a type of mineral that contains a sufficient concentration of metal that can be extracted profitably.
Why are ionic compounds soluble in water but not in organic solvents?
Ionic compounds dissolve in water because water molecules can surround and separate the ions, allowing them to move freely. In organic solvents, the ions are not effectively separated, so they remain insoluble.
Why do ionic compounds have high melting points?
Ionic compounds have strong electrostatic forces between cations and anions. Breaking these bonds requires a significant amount of energy, resulting in high melting points.
What happens when metals react with non-metals?
Metals lose electrons to form cations, while non-metals gain electrons to form anions. The electrostatic attraction between these oppositely charged ions results in the formation of an ionic bond.
Why is copper used for electrical wiring instead of iron?
Copper is a better conductor of electricity than iron and is also more resistant to corrosion.
Why does sodium react vigorously with water?
Sodium reacts vigorously with water because it is highly reactive and forms sodium hydroxide and hydrogen gas in an exothermic reaction.
What is an amphoteric oxide?
An amphoteric oxide is a metal oxide that can react with both acids and bases to form salts and water. Examples include aluminum oxide (Al₂O₃) and zinc oxide (ZnO).
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