Matter and Atomic StructureSection 3.3- State of Matter

Solids – form crystalsSubstances with densely packed particles

which may be ions, atoms, or molecules.Definite shape and definite volume.Crystalline structure= geometric patternsCrystals form symmetrical solid objects

Vocabulary

Crystalline StructureTable salt crystals = cubicVanadium crystals = hexagonal

Glasses

Window glassMolten material chills very rapidly;

atoms don’t have enough time to arrange in patterns.

Made of disordered silicon and oxygen SiO2

LiquidsParticles slide pass each other Do not have a definite shape, take the shape

of a container.Have definite volume

Gases

Particles move at very high speedsEvaporation – change of a liquid to a gasSublimation – slow change of state from a

solid, ice crystals, to a gas, water vapor, without and intermediate liquid state.

No definite shapeNo definite volume

Plasma

Plasma – hot, highly ionized, electrically conducting gases

Matter is heated- 5000co

Collisions are violent; electrons are knocked off

As a result= positive ions + free electronsExample- Stars, lightning, neon sign

Changes of State

Solids melt when they absorb thermal energyLiquids absorbs thermal energy, it

evaporatesGas cools, it releases thermal energy in

process called condensation (change from gas to a liquid)

First Law of ThermodynamicsMatter cannot be created or destroyed.

Law of conservation of matterEnergy cannot be created or destroyed

Law of conservation of energy

Matter and Energy can only change from 1 form to another.