16.1 Notes Kinetic Theory

KINETIC THEORY Kinetic Theory- An explanation of how particles in matter behave. The 3 Assumptions of Kinetic Theory: 1. All matter is composed of small particles. 2. These particles are in constant random motion Only time particles stop moving is at absolute zero or 0 Kelvin (-273ºC) 3. These particles are colliding with each other and the walls of their container.

Thermal Energy Thermal Energy- Total energy of a material’s particles including both kinetic (vibration movement within and between particles) and potential energy. – Particles at a higher temperature have more kinetic energy and  (therefore) the kinetic energy lowers with lower temperatures.

1st State of Matter Solid- Attraction between particles give a solid a definite shape and volume, but thermal energy in the particles cause them to vibrate in place. Melting Point- Point at which a solid begins to liquefy (or attractive bonds start to break apart)

1st State of Matter Cont. Heat of Fusion- amount of energy required to change a substance from a solid phase to a liquid phase – Heat is going into the solid and breaking the bonds between particles

TEMPTEMP TIME Solid Melting Point Heat of Fusion Change of States of Matter Graph

2nd & 3rd States of Matter Liquid- particles have more space between them and so it allows the particles to slide over each other causing thing them to flow and take the shape of their container – Definite Volume, Indefinite shape Gas- particles are in constant motion, move quickly and randomly and has more collisions taking place. They take the shape of their container, but have large spaces between the particles. – Indefinite volume and indefinite shape

2nd & 3rd States of Matter Cont. Heat of Vaporization- amount of energy required for the particles to overcome the attractive forces within the liquid. – Energy needed to brake the bonds holding a liquid together so it can become a gas. Boiling Point- Temperature at which the pressure of it’s vapor is equal to the pressure of the atmosphere. Particles are able to overcome the attractive forces of a liquid. – Lower altitudes have higher atmospheric pressure which cause the boiling point to rise (H 2 O boils above 100º) – Higher altitudes have lower atmospheric pressure which causes the boiling point to lower (H 2 O boils below 100º)

TEMPTEMP TIME Solid Melting Point Heat of Fusion Complete Change of States of Matter Graph Liquid Heat of Vaporization Gas

Diffusion Diffusion- The spreading of particles throughout a given volume until they are uniformly distributed – Goes from a high concentration to a low concentration. – So if I fart here, you’ll soon be able to smell it there. High conc. Low Conc.

4th State of Matter Plasma- Gas containing positively and negatively charged particles. – Plasma is neutral, it has an equal amount of negative and positive charged particles. Plasma particles are moving so quickly that their collisions cause electrons to be stripped off of atoms and put onto others. – Occurs in stars, lightening bolts, neon, fluorescent tubes, and auroras – 99% of matter in the universe is made up of matter.

Thermal Expansion Thermal Expansion- when temp. increases, the kinetic energy of particles increase and collide more often with each other and their container, causing an increase in the size of the substance. – Liquids- thermometers rise because liquid particles bump into each other causing the liquid to move up the thermometer tube. – Gases- hot air balloon rise because you heat the particles making them expand, the density decreases causing the balloon to rise.

Thermal Contraction Thermal Contraction- when temperatures decrease the KE of the particles decrease and collisions cease occurring as often and  the size of the substance decreases. –I–If you put a balloon in a freezer, it will shrink, because the particles aren’t hitting the sides of the balloon as much.