1. Temperature Does Not Change During a Change of State Heat of Fusion –Energy applied is used to change the state from solid to liquid (and vice versa), so temperature remains constant. –It takes energy to keep breaking or forming bonds. Heat of Vaporization –Energy applied is used to change the state from liquid to gas (and vice versa), so temperature remains constant. –It takes energy to keep breaking or forming bonds.

2. Sublimation Some materials change directly from a solid to a gas. State change from Solid directly to a Gas. Liquid state is skipped under normal circumstances. Particle bonds break “completely” when heated to a certain point. Sublimation vs. Deposition

3. Diffusion The movement of particles from an area of high concentration to an area of low concentration. Requires no energy. Spreads particles out evenly. Occurs faster in the gaseous state than in the liquid state. Why does Oxygen enter our bodies? How can diffusion be speeded up?

4. Ordinary evaporation is a surface phenomenon - some molecules have enough kinetic energy to escape. If the container is closed, an equilibrium is reached where an equal number of molecules return to the surface. The pressure of this equilibrium is called the saturation vapor pressure. saturation vapor pressure In order to evaporate, a mass of water must collect the large heat of vaporization, so evaporation is a powerful cooling mechanism. Evaporation heat loss is a major climatic factor and is crucial in the cooling of the human body.heat of vaporization cooling of the human body Evaporation

5. Ordinary evaporation is a surface phenomenon - since the vapor pressure is low and since the pressure inside the liquid is equal to atmospheric pressure plus the liquid pressure, bubbles of water vapor cannot form. But at the boiling point, the saturated vapor pressure is equal to atmospheric pressure, bubbles form, and the vaporization becomes a volume phenomena.evaporationliquid pressureboiling pointsaturated vapor pressure Evaporation vs Boiling

7. Electronegativity

9. Linus Pauling Electronegativity is defined as –The power of an atom in a molecule to attract electrons to itself. There is a numerical scale that lists the Electronegativity of all elements. Excluding the noble gases, the values tend to increase as you move to the right and up. The values tend to decrease as you go down and to the left. This is used to determine the ionic magnitude of a bond.

11. Some Numerical Electronegativities F4.0C2.5 O3.5S2.5 Cl3.0H2.1 N3.0Na.9 Br2.8K.8

12. Using Electronegativity One can tell the type of bond two atoms will form by calculating the difference between the two. –Ionic, Polar Covalent, or Pure Covalent Ionic EN > 2.0 Ionic/Polar Covalent EN: Between 1.6 and 2.0 Polar Covalent EN between 0.2 and 1.6 Pure Covalent EN < 0.2

13. EN: Between 1.6 and 2.0 If a metal is involved –Ionic If only nonmetals are involved –Polar Covalent