6.3 ; changes of state

Question	Answer
_____ is needed to melt a solid or boil a liquid.	ENERGY is needed to melt a solid or boil a liquid.
For any pure substance undergoing a change of state, its temperature:	stays the same while the change of state takes place
What changes of state happen at a substance's: a) melting point b) boiling point	a) melting + freezing b) boiling + condensation
What affects the melting and boiling point of a liquid?	any impurities in the substance
Give an example of the previous statement	the melting point of water is lowered if you add salt to the water
What happens during the horizontal lines (whilst the temperature stays the same)? Image: 393cd1e38fe4f8e3b3b6b9f738aebd4421cf3de7 (binary/octet-stream)	the extra heat added does not affect the temperature, but rather goes to overcoming the forces of attraction between particles
What is latent heat?	the energy transferred to a substance when it changes state- its 'hidden' by the substance because the temperature does not change at its melting/boiling point
Explain what fusion is.	it is sometimes used to describe melting because different solids can be 'fused' together when they melt
Compare evaporation and boiling	evaporation; happens at any temperature and at the surface of the liquid ≠ boiling; at the boiling point, when bubbles of vapour form inside the liquid + rise to the surface to release the gas

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	Created by Farha Idrees over 6 years ago

	Copied by Farha Idrees over 6 years ago