Chapter 10: The Kinetic Theory of Matter

Section 10.1: Physical Behavior of Matter

Main Idea: The common states of matter are solid, liquid and gas Compare characteristics of a solid liquid or gas Relate the properties of a solid, liquid, and gas to the kinetic theory of matter Distinguish among amorphous solids, liquid crystals, and plasmas

Classification

 Based on properties: position and movement of atoms ions or molecules

Solid

 has a fixed volume that cannot be compressed into a smaller volume  is rigid with a definite shape because the atoms, ions, or, molecules are in fixed positions

Liquid

 is flowing matter with a definite volume but an indefinite shape  takes the shape of its container

Gas

 flowing, compressible matter that has no definite volume or shape  spreads out to fill the space  particles are much farther apart than they are in solids and liquids  particles can be easily pushed together

Solid, Liquid and Gas

 Video on states of matter

Brownian Motion

  Robert Brown- 1827 Observed that particles in water (pollen grains) move continuously in random, irregular directions  Definition: constant, random motion of tiny chunks of matter  https://www.youtube.com/watch?v=hy-clLi8gHg

Only Water???

Water molecules are not the only molecules that display random motion

Kinetic Theory of Matter

 states that submicroscopic particles of all matter are in constant motion  Kinetic energy is the energy of moving objects

Kinetic Model of Gases

 A gas particle can change direction only when it strikes the wall of its container or another gas particle  Assumptions: Each gas particle rebounds without losing kinetic energy and without losing speed, but in a new direction  Collisions of particles in a gas are called elastic collisions because no kinetic energy is lost

Ideal gas

 gas with particles that are in constant motion but have no attraction for each other. The particles undergo elastic collisions.

 Except at very low temperatures or very high pressures, nearly all gases act as ideal gases

Gas Particles and Pressure

 Pressure is the force acting on a unit area of a surface Example: psi = pounds per in 2  Particles in a gas exert a force on each square cm of the walls of the container when the wall deflects them  Earth’s atmosphere (mixture of gases) exerts pressure also. Constant bombardment of molecules in the air

Kinetic Model of Liquids

 Particles of a liquid can slide past each other, but they are so close together that they don’t move as straight as gas particles

Kinetic Model of Solids

 Strong forces between particles explain the rigid structure of solids  Particles of a solid cannot move past each other, but they are in constant motion (vibration)  Particles occupy fixed positions in a well defined, 3 dimensional arrangement Crystal lattice- The arrangement, which is repeated throughout the solid  When a solid melts, its crystal lattices disintegrate and its particles lose their 3-dimensional pattern

Other forms of matter not classified as solids, liquids or gases http://education portal.com/academy/lesson/the-kinetic molecular-theory-properties-of-solids and-liquids.html#lesson

Amorphous Solid

Haphazard, disjointed, and incomplete crystal lattice Examples: candle wax, cotton candy, peanut butter https://www.youtube.com/watch?v=bzr-byiSXlA

Liquid Crystal

 materials that lose their rigid organization in only one or two dimensions when they melt  interparticle forces in a liquid crystal are relatively weak and their arrangement is easily disrupted  When the lattice is broken, the crystal can flow like a liquid    Liquid crystal displays (LCDS) are used in watches, calculators, etc. because they can change colors at specific temperatures https://www.youtube.com/watch?v=nAJgchCI3kg

Plasma

 an ionized gas that forms at very high temperatures  most common form of matter in the universe but least common on Earth (sun and stars)  can conduct electrical current and are electrically neutral (contain equal numbers of free electrons and positive ions)  are called high-energy states of matter because high energy is needed to separate and to maintain separation of the atoms into ions and electrons

Bose-Einstein Condensate (BEC)

 Predicted by Einstein in 1924, Created in 1995 (CU Boulder- Cornell/ Weiman)    a rare state (or phase) of matter that occurs at extremely low temperature, near the value of absolute zero (at zero- no particles move) Superfluid helium-4 that involve Bosons https://www.youtube.com/watch?v=nAGPAb4obs8

In the July 14, 1995 issue of Science magazine, researchers from JILA reported achieving a temperature far lower than had ever been produced before and creating an entirely new state of matter predicted decades ago by Albert Einstein and Indian physicist Satyendra Nath Bose. Cooling rubidium atoms to less than 170 billionths of a degree above absolute zero caused the individual atoms to condense into a "superatom" behaving as a single entity. The graphic shows three-dimensional successive snap shots in time in which the atoms condensed from less dense red, yellow and green areas into very dense blue to white areas. JILA is jointly operated by NIST and the University of Colorado at Boulder.

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Circle any examples you had written down Write 3 questions.