7.1

Question	Answer
7 . 2	Hi :)
Physical Changes	The changes where no new substances are formed.
Chemical changes	The changes where new substances are formed.
Expansion	When volume of an object increases and its density decreases.
Contraction	(The opposite of expansion) When the volume of an object decreases.
Evaporation	The process of turning liquid into gas (vapour).
Melting	The process of turning solid into liquid.
Condensation	The process of turning gas into liquid.
Freezing (solidification)	The process of turning liquid into solid
Precipitate	An event or situation that is undesirable.
what is :- solute solvent solution?	Solute : the solid that is been dissolved. Solvent : the dissolving liquid. Solution : the mixture that is formed.
Crystallisation	If the solvent is removed by evaporation, the solute particles can join together and form crystal. This process is known as crystallisation.
How can you detect a chemical change?	The presence of a new substance can be detected by: 1. seeing a new colour 2. smelling a gas or seeing bubbles 3. seeing a new solid forming in a clear solution 4. seeing or feeling a change in temperature.
what is the particle model	is the simplified of solid liquid and gasses
solids	the attraction between particular binds them tightly together
liquids	participial are packed tightly together to make them in compressible
gasses	particals are not stuck together to make them compressible

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	Created by Sadia M over 7 years ago

	Copied by Zahin Khan over 7 years ago