★ Must-know
📌 When a liquid is cooled below 0°C, it freezes and changes into a solid.
Further detail
Solid → liquid → gas: melting, then boiling or evaporation; reverse with condensation, freezing, and deposition.
★ Must-know
📌 Evaporation can happen at any temperature, whereas boiling happens at 100°C.
📌 At higher altitudes, water boils at less than 100°C because the air is thinner and the air pressure is lower.
Further detail
📌 Steam is visible, whereas water vapour is invisible.
Evaporation can occur at any temperature, whereas boiling occurs at 100°C.
1. What change of state occurs when liquid water becomes steam?
2. Which change of state occurs when a solid changes directly into a gas without becoming a liquid?
3. Which statement correctly distinguishes evaporation from boiling?
What is vaporization in terms of state change?
It is the change from liquid to gas.
Which changes of state involve going directly between solid and gas?
Sublimation and deposition.
What temperature can evaporation occur at?
Evaporation can happen at any temperature.
Why does water boil below 100°C at high altitudes?
Because the air pressure is lower due to thinner air.
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