States of Matter Section ity/states_of_matter/ ity/states_of_matter/

Kinetic Theory Kinetic Theory Kinetic Theory All matter is composed of small particles All matter is composed of small particles Particles are in constant random motion Particles are in constant random motion Particles collide with each other and the walls of their containers constantly Particles collide with each other and the walls of their containers constantly When particles collide- small amounts of energy are lost When particles collide- small amounts of energy are lost Solids- definite shape and volume- particles have strong attraction for each other, preventing motion Solids- definite shape and volume- particles have strong attraction for each other, preventing motion

Solids Thermal energy causes the particles to vibrate – KE Thermal energy causes the particles to vibrate – KE PE also causes some vibration- (energy due to the forces that act within or between particles) PE also causes some vibration- (energy due to the forces that act within or between particles) Higher temperatures- more vibration Higher temperatures- more vibration Temperature- the average KE of particles in a substance Temperature- the average KE of particles in a substance

Particle Motion No particle motion- absolute zero- 0K No particle motion- absolute zero- 0K Geometric arrangement of particles in a solid- determines chemical & physical properties of a solid Geometric arrangement of particles in a solid- determines chemical & physical properties of a solid Solids- particles are closely packed Solids- particles are closely packed

Particle Motion Different solids melt in different ways: Different solids melt in different ways: Amorphous -solid that softens and gradually turns into a liquid over a large temperature range – don’t form crystals Amorphous -solid that softens and gradually turns into a liquid over a large temperature range – don’t form crystals Crystalline solids- have set geometric structure-may melt normally or form liquid crystals Crystalline solids- have set geometric structure-may melt normally or form liquid crystals Liquid crystals start to flow during the melting phase but do not lose their ordered arrangement completely Liquid crystals start to flow during the melting phase but do not lose their ordered arrangement completely From solid to liquid- in solids, particles move slowly From solid to liquid- in solids, particles move slowly Heat is added-particles move faster Heat is added-particles move faster Eventually solid particles are moving fast enough- have enough KE- to overcome the attractive forces between the particles and escape the solid Eventually solid particles are moving fast enough- have enough KE- to overcome the attractive forces between the particles and escape the solid

Melting Melting Point- temperature at which a solid begins to liquefy. Melting Point- temperature at which a solid begins to liquefy. Heat of fusion- the amount of energy required to change a substance from the solid phase to the liquid phase at its melting point Heat of fusion- the amount of energy required to change a substance from the solid phase to the liquid phase at its melting point Particles of a liquid have more KE than particles of a solid Particles of a liquid have more KE than particles of a solid There is enough energy for particles to move past each other There is enough energy for particles to move past each other

Amorphous vs. Crystalline

Particle Motion Particles of a gas-have enough KE to overcome the attractions between them completely Particles of a gas-have enough KE to overcome the attractions between them completely Spread and fill the containers Spread and fill the containers Diffusion-spreading of particles throughout a container until they are uniformly distributed Diffusion-spreading of particles throughout a container until they are uniformly distributed Liquid to gas- some particles of a liquid move faster than others and escape the attractive forces of other particles- allows them to enter the gas phase Liquid to gas- some particles of a liquid move faster than others and escape the attractive forces of other particles- allows them to enter the gas phase Evaporation & Boiling- liquid into gas Evaporation & Boiling- liquid into gas Evaporation-particles must have enough KE to escape the attractive forces of the liquid Evaporation-particles must have enough KE to escape the attractive forces of the liquid

Particle Motion Boiling- the T at which the P of a vapor in the liquid is equal to the external P acting on the surface of the liquid Boiling- the T at which the P of a vapor in the liquid is equal to the external P acting on the surface of the liquid Lower external pressure like on a mountain means lower boiling point Lower external pressure like on a mountain means lower boiling point Higher external pressure like at sea level means higher boiling point Higher external pressure like at sea level means higher boiling point Heat of vaporization- amount of energy required to overcome the pressure at the surface of the liquid (E needed to boil) Heat of vaporization- amount of energy required to overcome the pressure at the surface of the liquid (E needed to boil) Plasma-gas consisting of positive and negative particles- most common state of matter in universe Plasma-gas consisting of positive and negative particles- most common state of matter in universe

Heating Curve A B C D E A- ice is being heated- energy is used to increase temperature B- ice is melting- heat of fusion - melting point – energy is used to overcome attractions C- liquid is heated up- energy is used to increase temperature D- liquid is changing to vapor- heat of vaporization- boiling point- energy is used to overcome attractions E - vapor is being heated- energy is used to increase temperature

Temperature & Matter When temperature increases- substances expand- thermal expansion When temperature increases- substances expand- thermal expansion Gases expand the MOST because particles have no attractions!! Gases expand the MOST because particles have no attractions!! When temperature decreases-substances contract When temperature decreases-substances contract Thermometers-energy is added- particles of the liquid move faster & farther apart-forces fluid upward through the thermometer Thermometers-energy is added- particles of the liquid move faster & farther apart-forces fluid upward through the thermometer

Temperature & Matter Water Hot air balloons rise- higher temperature= expansion = lower density = rises Hot air balloons rise- higher temperature= expansion = lower density = rises Water Water Has + and – regions Has + and – regions Decrease in temperature-particles get closer together Decrease in temperature-particles get closer together - from one particle attracts to + of other molecule - from one particle attracts to + of other molecule Empty spaces in ice are greater than those in water- ice is less dense than water Empty spaces in ice are greater than those in water- ice is less dense than water Water expands from liquid to solid- different from all other substances! Water expands from liquid to solid- different from all other substances!

Water