The Reactivity of Metals
Q1. Why do metals like iron rust over time but metals like gold don’t?
Iron reacts with oxygen and water in the air, forming rust (iron oxide). Gold, on
the other hand, does not react easily with oxygen or water because it is a
"noble metal." Noble metals like gold are very stable and don’t corrode easily.
Example of a common chemical reaction from daily life:
When you light a candle, the wax reacts with oxygen from the air to produce
carbon dioxide, water, and heat. This is called combustion.
Q2. How can you identify that a chemical reaction is taking place?
A chemical reaction is happening if you notice:
A change in color (like iron turning reddish-brown when it rusts).
A gas being produced (like bubbles in vinegar and baking soda).
A change in temperature (like the warmth of a burning candle).
A new substance being formed (like the solid rust on iron).
Substances or elements in open air that cause reactions are:
The air around us contains:
Oxygen (causes rust on iron).
Water vapor (helps speed up rusting).
Carbon dioxide (can react with some metals over time).
These substances can cause metals to react and form new materials, like
rust.
Metals used in daily life and appearance changes:
Iron: Used in gates and fences; it rusts and turns reddish-brown when
exposed to air and water.
Copper: Used in coins and wires; it turns green over time because of a
reaction with oxygen and moisture (forming patina).
Silver: Used in jewelry; it tarnishes and turns black due to a reaction with
sulfur in the air.
Q3. Which metals react vigorously with oxygen?
Q1. Why do metals like iron rust over time but metals like gold don’t?
Iron reacts with oxygen and water in the air, forming rust (iron oxide). Gold, on
the other hand, does not react easily with oxygen or water because it is a
"noble metal." Noble metals like gold are very stable and don’t corrode easily.
Example of a common chemical reaction from daily life:
When you light a candle, the wax reacts with oxygen from the air to produce
carbon dioxide, water, and heat. This is called combustion.
Q2. How can you identify that a chemical reaction is taking place?
A chemical reaction is happening if you notice:
A change in color (like iron turning reddish-brown when it rusts).
A gas being produced (like bubbles in vinegar and baking soda).
A change in temperature (like the warmth of a burning candle).
A new substance being formed (like the solid rust on iron).
Substances or elements in open air that cause reactions are:
The air around us contains:
Oxygen (causes rust on iron).
Water vapor (helps speed up rusting).
Carbon dioxide (can react with some metals over time).
These substances can cause metals to react and form new materials, like
rust.
Metals used in daily life and appearance changes:
Iron: Used in gates and fences; it rusts and turns reddish-brown when
exposed to air and water.
Copper: Used in coins and wires; it turns green over time because of a
reaction with oxygen and moisture (forming patina).
Silver: Used in jewelry; it tarnishes and turns black due to a reaction with
sulfur in the air.
Q3. Which metals react vigorously with oxygen?
