Chapter 3: States of Matter Ch. 3.1: Solids, Liquids, and Gases Ch. 3.3: Phase Changes

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 Fly through this

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. Fly through this

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.

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. STOP HERE 1/29

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.

Explaining the Behavior of… Gases – high KE, there are forces of attraction among the particles in all matter, BUT under ordinary conditions, scientists ignore the forces of attraction in gas. Liquids – lower KE than gases, are closer to each other, and the attractions between particles do affect the movement Solids – lower KE than liquids, closer together, stronger attraction between particles

Forces holding particles together Thermal Energy Thermal energy = Kinetic energy + Potential energy Forces holding particles together Moving Energy

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)

Ch. 3.3: Phase Changes Phase change – reversible physical change that occurs when a substance changes from one state of matter to another

Solid Liquid Gas States of Matter Freezing Vaporization Deposition Sublimation Melting Freezing Start here on 2/6 lecture day to review S,L,G and intro heating curve. What do you know about Solids regarding particle arrangement, shape, volume, behavior? Liquids? Gases? Draw chart. Phase changes: add energy as you go around clockwise, take away energy as you go around counter clockwise Vaporization Liquid Gas Condensation

Ideal Gases We are going to assume the gases behave “ideally”- in other words, they obey the Gas Laws under all conditions of temperature and pressure An ideal gas does not really exist, but it makes the math easier and is a close approximation. Particles have no volume? Wrong! No attractive forces? Wrong! Helps with KTM comp assign

Ideal Gases There are no gases for which this is true (acting “ideal”); however, Real gases behave this way at a) high temperature, and b) low pressure. Because at these conditions, a gas will stay a gas! Helps with KTM comp assign

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.

Melting Point vs. Boiling Point To become a liquid, the particles gain enough KE to slip out of their ordered arrangement Heat of fusion: energy required to change a solid to a liquid. 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

Pre-teach vocab: Latent Heat Latent Heat (enthalpy) is the "hidden" heat when a substance absorbs or releases heat without producing a change in the temperature of the substance, eg, during a change of state.

Pre-teach vocab: Latent Heat Latent Heat (enthalpy) of Fusion is the heat absorbed per mole when a substance changes state from solid to liquid at constant temperature (melting point). Latent Heat (enthalpy) of Vaporization (vaporisation) is the heat absorbed per mole when a substance changes state from liquid to gas at constant temperature (boiling point). Latent Heat (enthalpy) of Sublimation is the heat absorbed per mole when a substance changes state from solid to gas, without going through the liquid phase, at constant temperature. Pre-teaching vocabulary

Adding energy changes the state of matter! As you move to the right, more energy is required and as you move to the left, more energy is removed If this were a temperature vs. energy graph, where would the latent heat be? How do you know?

Heating Curve Axes are labeled: y axis is temperature, x axis is time or energy

Heating Curve explanation A substance is heated at a uniform rate: Temperature of the solid rises uniformly until the melting point is reached. At the melting point, heat is absorbed and used to melt the solid without any temperature change (latent heat of fusion), all the energy is going into weakening the intermolecular forces between the particles in the solid.

Heating Curve explanation cont When all the solid has melted to a liquid, the temperature starts to increase uniformly again until the boiling point is reached. At the boiling point, heat is absorbed without any change in temperature (latent heat of vaporization), all the energy absorbed is being used to overcome the intermolecular forces between the particles in the liquid. When all the liquid has been vaporized to gas the temperature will once again increase

Latent Heat Latent Heat (enthalpy) is the "hidden" heat when a substance absorbs or releases heat without producing a change in the temperature of the substance, eg, during a change of state. Latent Heat (enthalpy) of Fusion is the heat absorbed per mole when a substance changes state from solid to liquid at constant temperature (melting point). Latent Heat (enthalpy) of Vaporization (vaporisation) is the heat absorbed per mole when a substance changes state from liquid to gas at constant temperature (boiling point). Latent Heat (enthalpy) of Sublimation is the heat absorbed per mole when a substance changes state from solid to gas, without going through the liquid phase, at constant temperature. Kind of skip

Heating Curve of a liquid **Label picture! END OF LECTURE: think-pair-share describing heating curve of water using vocab: s, l, g, latent heat, energy, intermolecular forces, etc.