States of Matter Phase Changes

Solids Definite volume and definite shape Particles are tightly packed in fixed positions Vibrate back and forth Crystalline solids – particles have a regular, repeating pattern; have a specific melting point; sugar, salt Amorphous solids – particles are randomly arranged; no specific melting point, become softer; plastic, glass, butter Has the lowest energy level of the three states

Liquids Have definite volume but not definite shape Particles are closely packed but move freely around each other Fluid – they flow Surface tension – particles pull in ward and form a “skin” Viscosity – the resistance to flow high viscosity = honey, molasses, syrup low viscosity = water, vinegar, koolaid Has the middle level of energy of the three states

Gases Do not have definite volume or definite shape Particles spread out to fill any space, changing shape and volume fluid Has the highest energy level of the three states

Melting Solids Liquids Particles speed up Gain energy Endothermic change Freezing Particles slow down Lose energy Exothermic change

Liquids Condensation Particles slow down Lose energy Exothermic change Vaporization Boiling – occurs throughout the liquid Gas Particles speed up Gain energy Evaporation – occurs of the Surface of the liquid Endothermic change

Solids Deposition Particles slow down Lose energy Sublimation Exothermic change Particles speed up Gain energy Gas Endothermic change