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Solids , Liquids, and Gases

Solids , Liquids, and Gases. 9-3. Mariajose Burgos Marco Aguilar Michelle Casanova Jan Rischbieth. SOLIDS.

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Solids , Liquids, and Gases

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  1. Solids,Liquids,andGases • 9-3 Mariajose BurgosMarco Aguilar Michelle Casanova Jan Rischbieth

  2. SOLIDS A solid has a definite shape and a definite volume. The particles in a solid are packed up closely together and vibrate in place. This fixed, closely packed arrangement of particles causes a solid to have a definite volume and shape. Crystalline solids: These solids have regular repeating patterns which create crystals. Examples: salt, sugar, and snow. Crystalline solids melt at a specific temperature. Amorphous solids: Particles are not arranged in a regular pattern. Examples: plastics, rubber, and glass. An amorphous solid does not melt at a distinct temperature. Instead, it may become softer and softer of change into other substances.

  3. Liquids • A liquid has a definite volume but no definite shape of its own. Particles in a liquid are packed almost as closely as in a solid. However, the particles in a liquid move around one another freely. • Because its particles are free to move, a liquid has no definite shape. A liquid is also called a FLUID: “a substance that flows.”

  4. PROPERTIES OF LIQUIDS • Surface Tension:is the result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together. • Viscosity: a liquid’s resistance to flowing, which depends on the size and shape of its particles and the attractions between the particles.

  5. GASES • A gas is a state of matter with no definite shape or volume. A gas is also a fluid like liquid. As gas particles move they spread apart moving in all directions, filling all the space available, because of this they have no definite shape and no definite volume.

  6. CHANGES OF STATE • CHANGES BETWEEN SOLID AND LIQUID:MELTING • MELTING: The change of state from a solid to a liquid. Chemists often compare melting points when trying to identify an unknown material. Example: Melting point of pure water is 0 degrees C. • MELTING POINT: The specific temperature at which melting occurs. • Thermal energy makes the water molecules vibrate faster, raising their temperature. At its melting point, the particles of a solid substance are vibrating so fast that they break free from their fixed positions.

  7. Liquid to Solid • CHANGES BETWEEN SOLID AND LIQUID: FREEZING • FREEZING: The change of state from solid to liquid. • At its freezing temperature, the particles of a liquid are moving so slowly that they begin to form regular patterns. • EXAMPLE: When you put water into a freezer, it loses energy to the cold air. The water molecules move more and more slowly and eventually they become ice.

  8. Liquid to Gas CHANGES BETWEEN LIQUID AND GAS • VAPORIZATION: The change from a liquid to a gas. Vaporization takes place when the particles in a liquid gain enough energy to form a gas. Two main types of vaporization are evaporation and boiling. • EVAPORATION:Vaporization that only takes place on the surface. Example: shrinking puddle. • BOILING:Another kind of vaporization that occurs throughout the liquid. It occurs when a liquid changes to a gas below, as well as at, the surface. • BOLING POINT AND AIR PRESSURE:The boiling point of a substance depends on the air above it. The lower the pressure, the less energy needed for the particles of the liquid to escape into the air.

  9. Gas to Liquid • CONDENSATION • Condensation is the opposite of vaporization. It occurs when particles in a gas lose enough thermal energy to form a liquid. • Example: clouds form when water vapor in the atmosphere condenses into liquid droplets. When the droplets get heavy enough, they fall to the ground as rain.

  10. Solid to Gas CHANGES BETWEEN SOLID AND GAS SUBLIMATION: The change from a solid to a gas. Sublimation occurs when the surface particles of a solid gain enough energy that they form a gas. During sublimation, particles of a solid do not pass through the liquid state. One example of sublimation is dry ice, (solid carbon dioxide). CO2 cannot exist as a liquid so instead of melting, it changes directly into a gas.

  11. GRAPH: CHANGES OF STATE Deposition Freezing Condensation Melting Vaporization Sublimation SOLID LIQUID GAS

  12. Gas Behavior • When working with a GAS, you must know its volume, temperature, and pressure. • Remember: Volume is the amount of space that matter fills. Temperature is a measure of the average energy of random motion of the particles in a substance. • Particles in gas move very fast so they collide with each other and with the walls of their container. This causes the gas to push on the walls. • PRESSURE of the gas is the force of its outward push divided by the are of the walls of the container. Pressure is measured in units of pascals (Pa) or kilopascals (kPa). PRESSURE=FORCE/AREA

  13. The firmness of a gas-filled object comes from the pressure of the gas. Air inside a pumped basketball has a higher pressure that the air outside because there is a greater concentration of gas particles inside the ball. When air leaks OUT of a basketball, the pressure DECREASES. Even if the ball has a tiny hole, air leaks because the high pressure inside the basketball causes the particles to hit the inner surface of the ball. Therefore, particles reach the hole and escape. Low concentration of gas particles High concentration of gas particles. Basketball: HIGH PRESSURE Basketball: LOW PRESSURE

  14. Pressure and Volume… • In the 1600’s Robert Boyle found that when the pressure of a gas at constant temperature is increased, the volume of the gas decreases. When the pressure is decreased, the volume increases. • Boyle’s founding is called BOYLE’S LAW.

  15. PRESSURE AND TEMPERATURE The faster gas particles move, the more frequently they are to collide with the walls of the container and the greater the force of the collision. Recall: The higher the temperature of a substance, the faster its particles are moving. When the temperature of a gas at constant volume, which means the gas is in a closed container, is increased, the pressure of the gas increases. When the temperature is decreased the pressure of the gas decreases.

  16. CHARLE’S LAW • Charles found that when the temperature of a gas increased at constant pressure, its volume increases. When the temperature of the gas is decreased at constant pressure, its volume decreases. In the next slide you’ll see an example.

  17. GRAPHING GAS BEHAVIOR • Graph: A diagram that tells how two variables, or factors that change, are related. • Origin: point (0, 0) • Directly proportional: When a graph of two variables is a straight line passing through the origin. • Ex.) the graph of Charles`s law shows that the volume of a gas is directly proportional to its Kelvin temperature under constant pressure. • Vary inversely: When a graph of two variables forms this kind of curved lined. • Ex.) The graph for Boyle’s law shows that the pressure of a gas varies inversely with its volume at constant temperature.

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