Physical ChangesChapter 7 Lesson 3

Physical ChangeA change in size, shape, form, or state of

matterMatter’s identity stays the sameMatter does not become something different

State of MatterMovement of particles must changeThermal energy (heat) is added or removed

Adding Thermal EnergyParticles move fasterTemperature increasesSolid to Liquid

Particles move too fast for attractive force to hold them together – reaches melting point

Liquid to GasParticles move too fast for attractive force to

hold them together – reaches boiling point

SublimationSolid changes directly into a gas without first

being a liquid Example: dry ice (frozen carbon dioxide), solid

iodine

Removing Thermal EnergyParticles slow downTemperature decreasesGas to liquid

Particles slow down enough for attractive forces to pull the particles close together – condensation

Liquid to solidParticles slow down enough for attractive

forces to pull the particles close together - freezing

Freezing and meltingReverse processesOccur at the same temperature

Boiling and condensationReverse processesOccur at the same temperature

DepositionGas changes directly into a solid without first

being a liquid Example: frost

Opposite of sublimation

DissolvingPhysical change because the identities of the

substances have not changedExample: salt water

Can be reversed by boiling

Conservation of MassMass is conserved because it remains the

same after a change, such as a physical change

The particles of matter that are present before a physical change are the same as those present after the physical change

If a sample of water has a mass of 200 g and the final solution has a mass of 230 g, how much solute dissolved in the water?