States of Matter The Kinetic Theory 1. All matter is composed of small particles (atoms, molecules, or ions). 2. Particles are in constant, random motion, therefore they have kinetic energy. 3.The different particle arrangement, how much they move and how they move determines the state of matter.
Phase Properties Particle Properties Phase Proximity Energy Motion Volume Shape Solid close little vibrational definite definite Liquid close moderate rotational definite indefinite Gas far apart a lot translational indefinite indefinite
Temperature, Heat, and Thermal Energy 1. Temperature is related to the average kinetic energy of the particles in a substance.
TEMPERATURE SCALES 2. Other Important Facts Temperature scales: Fahrenheit scale (ºF) Celsius scale (º C ) Kelvin scale (º K ) Absolute Zero: the lowest temperature in the Kelvin scale is 0 ºK, which is called absolute zero. Absolute zero is the temperature at which all molecular motion stops. It is not possible to actually reach absolute zero, although temperatures very close to 0 ºK have been reached in laboratories. Thermometer: device used to measure temperature. Thermometers can measure temperature because of a property called thermal expansion. Thermal Expansion: is the increase in volume of a substance because of an increase in temperature. As a substance’s temperature increases, its particles move faster and spread out. So, there is more space between them, and the substance expands.
3. SI unit for temp. is the Kelvin a. K = C + 273 (10C = 283K) b. C = K – 273 (10K = -263C) 4. Thermal Energy – the total of all the kinetic and potential energy of all the particles in a substance.
5. Thermal energy relationships a. As temperature increases, so does thermal energy (because the kinetic energy of the particles increased). b. Even if the temperature doesn’t change, the thermal energy in a more massive substance is higher (because it is a total measure of energy).
a. The flow of thermal energy from one object to another. Cup gets cooler while hand gets warmer 6. Heat a. The flow of thermal energy from one object to another. b. Heat always flows from warmer to cooler objects. Ice gets warmer while hand gets cooler
7. Ways Thermal Energy can be Transferred Thermal energy can be transferred in three ways: Radiation, Conduction, and Convection. Radiation: is energy that travels by waves in all directions from its source. Conduction: is the transfer of thermal energy from particle to particle through a material when there is a temperature difference. Particles do not travel from one place to another, they simply move in place, bumping into each other and transferring energy from faster-moving particles to slower-moving ones. Convection: transfers thermal energy when particles move from one place to another where there is a difference in temperature. This is most common in gases and liquids.
8. Conductors & Insulators Conductors: materials through which it is easy to transfer thermal energy. Most metals are good conductors examples are gold, silver, and copper. Insulators: materials that do not allow thermal energy to be conducted easily. Examples: plastic, wood, rubber, ceramic tiles, and several layers of cloth.