Matter and Thermal Energy PDF

Matter and thermal energy Gas state Kinetic theory- Explanation of how the particles in gases behave 1) Gas particles are separated with lots of empty spaces 2) Gas particles are in constant, random motion....

Matter and thermal energy Gas state Kinetic theory- Explanation of how the particles in gases behave 1) Gas particles are separated with lots of empty spaces 2) Gas particles are in constant, random motion. 3) The collisions between gas particles are elastic Gas state Pressure of gas in a container Collision between the particles and the container’s side wall cause the gas pressure inside. Liquid state Particles are: 1) Constantly moving but less quickly than particles in gas 2) Have less kinetic energy than those in the gas 3) Less able to overcome attractions to each other- packed more tightly 4) Liquid cannot be compressed; it can only change shape to fit the container Solid state Solid has- 1) Definite shape and volume 2) Particles are closely packed together 3) Still in motion of vibrating, do not have much kinetic energy 4) Cannot be compressed or change shape Crystalline and Amorphous Crystalline: Amorphous: 1) Particles arranged in 1) Particles that do not have a regular geometric patterns crystalline form 2) Have a definite melting 2) No definite melting point point (will get softer and softer Examples: Salt, Sugar, sand before liquid) Thermal energy in the particles In solid: Attraction between particles hold them tightly in place Offer solid- definite shape/volume Particles still able to vibrate- due to the thermal energy Thermal energy-total energy of a material particle (Kinetic energy and potential energy of particle) Temperature represent the average kinetic energy of particles in the substance. Changes in state Thermal energy added into a system: 1) Part of the particles move faster, collide on the slower particles 2) Energy transferred in this process Melting vs. freezing Kinetic energy > attractive force 🡪 crystalline structure is broken Melting point: the temperate at which a solid becomes a liquid Heat of fusion: the energy required to change a substance from solid to liquid at its melting point. Melting and freezing Collision between the particles cause solid to melt Liquid particles slow down after the collision🡪 less kinetic energy🡪 temperature drop Melting vs. freezing Freezing: energy removes from the liquid particles🡪 molecules become fixed into position Freezing point: the temperature at which a liquid turns into solid. Vaporization and condensation Vaporization: when liquid becomes gas Particles move fast enough 🡪overcome the attraction between each other Condensation: process of gas becomes liquid Reverse process of vaporization Vaporization and condensation 2 ways of vaporization: evaporation & boiling Evaporation only occur on the surface of a liquid; particles need to have enough kinetic energy to overcome the attraction of the liquid Boiling: occurs through out the liquid at a specific temperature Vaporization and condensation Boiling point: temperature at which the liquid vapor pressure = external pressure acting on the liquid surface Heat of vaporization: the amount of energy required for liquid at its boiling temperature to become a gas Is a liquid going to become gas if we stop heat it up after it just reach the boiling temperature? Sublimation At certain pressure, some solid can directly change into gas state without going through the liquid state- sublimation Dry ice(solid carbon dioxide)🡪 gas Heating curves Shows how temperature change over time as thermal energy is continuously added At melting / boiling point, thermal energy was used to overcome the attractive forces between the particles- temperature remain constant during the process. Plasma state Matter has enough energy to overcome the attraction between particles and the attraction within atoms Atoms collide with each other with great amount of force Examples -Lightning -Fluorescent Light Bulbs -Sun -Plasma Display Panels(TV) -Stars -Aurora Borealis (interaction of earth’s -Neon “Lights” magnetic field and a plasma) Fact about Plasma state An ionized gas OR charged gas. (+ and – charged electrons) Some of the electrons break free from, but travel with, their nucleus Most common state of matter in the universe. Much of the mass of the universe is plasma Thermal expansion Temperature rise- particles move faster and further apart🡪 causing expansion of the volume🡪 thermal expansion Temperature drop- substance contract Thermometer- liquid undergoing thermal expansion- liquid in the thermometer expand - rise in the narrow tube as the temperature increase🡪 - we can read the numbers Hot air balloons Thermal expansion of the air- Volume increase while mass is not change🡪 Air density decrease🡪 Hot air tend to float upward Water as an exception As temperature drop, water molecules move closer to each other until reach 4 ºC When freezes, water expand the volume- Liquid water molecules have highly positive area and highly negative area, they form hydrogen bond with neighbors when temperature drop from 4ºC to 0ºC, molecules align and empty spaces occur🡪 causing the water volume expand Solid or liquid? Amorphous solid- soften and melt in a range of temperature(glasses) Liquid crystal- start flow during the melting phase, not losing the ordered arrangement completely.(liquid crystal display)