Latent Heat of Fusion
What is latent heat of fusion?
Heat needed to change a solid into a liquid without temperature change.
What is latent heat of vaporisation?
Heat needed to change a liquid into gas without temperature change.
What is evaporation?
When a liquid turns into a gas.
What is sublimation?
When a solid turns directly into a gas.
What is freezing?
Freezing is when a liquid turns into a solid by cooling.
What happens to temperature during fusion?
It remains constant.
Does water need more or less heat to turn into steam than alcohol?
More heat.
Does evaporation happen faster when it’s hot or cold?
It happens faster when it’s hot.
Can you name something that sublimates?
Dry ice (carbon dioxide).
How does pressure affect freezing?
Higher pressure lowers the freezing point of water.
Give an example of fusion.
Ice melting into water.
What happens to the temperature of water while it boils?
It stays the same.
Can evaporation happen without boiling?
Yes.
Why does sublimation happen?
It happens when the solid’s vapor pressure is higher than the surrounding air pressure.
Why do salty liquids freeze at lower temperatures?
Salt lowers the freezing point of water.
Does a substance absorb or release heat during fusion?
It absorbs heat.
Does boiling water absorb heat or release heat?
It absorbs heat.
Does evaporation cool down the air?
Yes, it makes the air cooler.
How is sublimation different from evaporation?
sublimation goes from solid to gas, while evaporation goes from liquid to gas.
How does freezing affect food?
Freezing can change the texture and make food softer when thawed.
At what temperature does ice melt?
0°C.
What is water after it boils?
It turns into steam (gas).
Does evaporation happen faster in dry or wet air?
It happens faster in dry air.
What is sublimation used for in food?
Freeze-drying uses sublimation to remove water from food by turning ice directly into vapor.
What’s the difference between freezing and supercooling?
Freezing turns liquid into solid, while supercooling keeps liquid below freezing without solidifying.