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Chapter 16. Solids, Liquids and Gases. Kinetic Theory. Explains how particles in matter behave. Three assumptions: 1. All matter is composed of small particles (atoms, molecules, and ions). 2. These particles are in constant, random motion.
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Chapter 16 Solids, Liquids and Gases
Kinetic Theory • Explains how particles in matter behave. • Three assumptions: • 1. All matter is composed of small particles (atoms, molecules, and ions). • 2. These particles are in constant, random motion. • 3. These particles are colliding with each other and the walls of their container.
Kinetic Theory • Imagine a room filled with tiny bouncing ping pong balls. That is what atoms are like! • A very small amount of energy is lost with each collision.
Thermal Energy • Thermal energy = Kinetic energy + Potential energy Moving Energy Forces holding particles together
Temperature • Temperature: the measure of average kinetic energy • Quick definition: How fast are the particles moving? • Absolute Zero: no more thermal energy can be removed; particles barely moving at all. • -273.15 °C or 0 K (kelvin)
Statesof Matter Freezing Boiling
Chemical & Physical Properties • Chemical Properties: How a substance reacts. Examples: Flammability, reactions to light • Changes into a new substance during the reaction. • Physical Properties: Characteristics you can observe. Examples: Color, boiling point, magnetic • Doesn’t change what the substance is.
Solid State • Particles packed tightly together and constantly vibrating in place. • Form a geometric arrangement, which give it specific chemical and physical properties. • Solids have their own shape and a definite shape and volume
Liquid State • Particles packed tightly together, but are able to move around more freely. • Liquids can flow; their particles can slide past each other. • Liquids have a definite volume, but take the shape of their container.
Gas State • Particles have enough kinetic (moving) energy to separate and spread far apart or contract. • Gases do not have a fixed volume or shape. They fill up the space they are in.
Vaporization • A particle has enough kinetic (moving) energy to escape from other particles. • 2 ways: • Evaporation: happens on surface of a liquid at room temperature • Boiling: happens throughout liquid at a specific temperature.
Boiling Point • To become a gas, the pressure of a vapor in the liquid must be higher than the pressure of the air on the surface. • Heat of vaporization: energy required to change a liquid to a gas.
Diffusion • Diffusion:Spreading of particles throughout a given volume unit they are evenly distributed. • Example: spraying perfume in a room • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html
Adding energy changes the state of matter! **Sketch picture!
Heating Curve of a liquid **Sketch picture!
Plasma • Most common state of matter in the universe. • Plasma: matter made of + and – charged particles, but is neutral overall. • The collisions are very intense and cause electrons to be taken away. • Examples: the sun, lightening bolts, neon and fluorescent tubes.
Behavior of Gases • Pressure = Force/Area (P = F/A) • Unit: Pascals (Pa) = 1 N/m2 • At sea level, atomospheric pressure = 101.3 kilopascals (kPa) **Sketch picture & chart !
Behavior of Gases • Balloons stay inflated because of the atoms colliding with the walls of the container. • If you add air to the balloon, there are more air particles. Therefore, more collisions are occurring and the container expands.
Boyle’s Law • ↓ volume = ↑pressure (constant temperature)
Boyle’s Law • P1V1 = P2V2 • Example: • A balloon has a volume of 10.0 L at a pressure of 100 kPa. What will the new volume be when the pressure drops to 50 kPa? • P1 = • V1 = • P2 = • V2 = P1V1 = P2V2 100 * 10 = 50 * V2 1000 = 50 * V2 1000 = 50* V2 50 50 100 kPa 10.0 L 20 L = V2 50 kPa 20 L
Pressure-Temperature Law • What happens when you heat a container that can’t change shape? • ↑ temperature = ↑ pressure • Pressure builds until the container can’t hold it any more and it explodes.
Charles’s Law • ↑ temperature = ↑ volume (constant pressure)
Charles’s Law • V1/T1 = V2/T2 (temp must be in kelvin) • Example: • A balloon has a volume of 2.0 L at a temperature of 25ºC. What will the new volume be when the temperature drops to 10ºC? • V1 = • T1 = • V2 = • T2 = V1/T1 = V2/T2 2.0 = V2298 283 298 * V2 = 2.0 * 283 2.0 L V2 = 2.0 * 283 298 25ºC + 273 = 298 K 1.9 L V2 = 1.9 L 10ºC + 273 = 283 K