Chemistry

1 Chapter 10 - Liquids and Solids 10.1 Intermolecular Forces A. Dipole-Dipole Forces 1. Attraction between molecules with dipole moments a. Maximizes (+) ----- ( - ) interactions b. Minimizes (+) ----- ( + ) and (-) ----- ( - ) interactions 2. About 1% of strength of ionic bonds a. Unimportant in gas phase due to distance between molecules B. Hydrogen Bonding 1. Special dipole-dipole attraction a. Hydrogen covalently bonded to highly electronegative elements (N, O, F) has a higher than normal d+ charge 2. Bond strength is higher than other dipole-dipole attractions 3. Important in the bonding of molecules such as water and DNA C. London Dispersion Forces 1. Instantaneous dipoles a. Random movement of electrons can create a momentary

AP Chemistry A. Allan Chapter 8 Notes - Bonding: General Concepts 8.1 Types of Chemical Bonds A. Ionic Bonding 1. Electrons are transferred 2. Metals react with nonmetals 3. Ions paired have lower energy (greater stability) than separated ions B. Coulomb's Law 1. ? ? ? ? ? ? ? ? ?= - r QQ E nmJx 21191031.2 a. E = energy in joules b. Q1 and Q2 are numerical ion charges c. r = distance between ion center in nanometers d. negative sign indicates an attractive force C. Bond Length (covalent) 1. Distance at which the system energy is at a minimum 2. Forces at work a. Attractive forces (proton - electron) b. Repulsive forces (electron - electron, proton - proton) 3. Energy is given off (bond energy) when two atoms achieve greater stability together than apart

AP Chemistry A. Allan Chapter Six Notes - Thermochemistry 6.1 The Nature of Energy A. Definition 1. Energy is the capacity to do work (or to produce heat*) a. Work is a force acting over a distance (moving an object) b. *Heat is actually a form of energy. (1) chemicals may store potential energy in their bonds that can be released as heat energy B. Law of Conservation of Energy 1. Energy can be converted from one form to another, but cannot be created or destroyed a. Potential energy (1) energy due to position or composition b. Kinetic energy (1) energy due to the motion of an object (2) vmKE 22 1= C. Heat and Temperature 1. Temperature reflects random motion of particles in a substance 2. Temperature indicates the direction in which heat energy will flow

AP Chemistry A. Allan Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry 4.1 Water, the Common Solvent A. Structure of water 1. Oxygen's electronegativity is high (3.5) and hydrogen's is low (2.1) 2. Water is a bent molecule 3. Water is a polar molecule B. Hydration of Ionic Solute Molecules 1. Positive ions attracted to the oxygen end of water 2. Negative ions attracted to the hydrogen end of water C. Hydration of Polar Solute Molecules 1. Negative end of polar solute molecules are attracted to water's hydrogen 2. Positive end of polar solute molecules are attracted to water's oxygen D. "Like Dissolves Like" 1. Polar and ionic compounds dissolve in polar solvents like water 2. Nonpolar compounds like fats dissolve in nonpolar solvents like ____ ?_____

AP Chemistry A. Allan Chapter 2 Notes - Atoms, Molecules and Ions 2.1 The Early History Refer to the Chemistry History Timeline for this chapter 2.2 Fundamental Chemical Laws A. Law of Conservation of Mass 1. "Mass is neither created nor destroyed" 2. Translation: In ordinary chemical reactions, the total mass of the reactants is equal to the total mass of the products B. Law of Definite Proportion 1. "A given compound always contains the same proportions of elements by mass" 2. Translation: Compounds have an unchanging chemical formula C. Law of Multiple Proportions 1. "When two elements form a series of compounds, the ratios of the masses of the second element that combine with one gram of the first element can always be reduced to small whole numbers