CHEM 2200 1nd EditionExam # 1 Study Guide Lectures: 1-7Lecture 1 (August 21)- Equations:o Ideal Gas Law – PV=nRTo Clausius-Clapeyron Equation: lnP2 = -ΔvapH (1 - 1) lnP1 R T2 T1- In real gasses (not ideal) intermolecular forces are at work- Four kinds of IMF’s o Hydrogen Bondingo Dipole-dipole forces: between molecules with permanent partial chargeso Ion-ion forces: between ionso London Dispersion forces: between nonpolar molecules (occurs in ALL bonding situations) – two induced dipoles- The greater the forces of attraction between molecules, the greater the energy that must be applied to separate them- Boiling point increases with atomic mass, but molecules with greater charges will have higher boiling points- Hydrogen bonding molecules to not follow that molar mass trend for boiling point, they have much higher boiling points due to the large electronegativity charges- Hydrogen bonding explains why water has such a high boiling point and is lower in density in the solid form- Polar molecules can create a temporary dipole in nonpolar molecules- Vaporization: the process in which a substance in the liquid state becomes a gas- Vaporization is an endothermic process- Condensation is the reversed process of vaporization (enthalpy change is equal but opposite in sign to that of vaporization)- Vapor pressure is created when there is a liquid in a closed container and some of its molecules are changing to the gas formo Can be measures one the two liquids reach equilibrium- Normal Boiling Point is the temperature at which the external pressure is 760 mmHgo Normal boiling point for water is 100° C- Molecules at the surface of liquids only interact with molecules at or immediately around the surface (reason for surface tension)- Viscosity increases with increasing molecule size- Unit cell: smallest repeating unit that makes up a solido Primitive cubic – just the four corner molecules Total atoms – 1 o Body-centered cubic – has an additional particle, same type as in corners, in the center of the cube Total atoms – 2o Face-centered cubic – additional particle on each of 6 faces Total atoms – 4 - Semiconductors are given their name because they do not conduct electricity easily but can be prompted to do so by the input of energyo Contain a band gap between molecular orbital bands Gap acts as a barrier to keep electrons from entering the higher energy stateo P-type semiconductor: a semiconductor where positive holes can appearo N-type semiconductor: a semiconductor consisting of negative charge carriers- Lattice Energy: a way to measure the strength of the bonding in an ionic crystal lattice (high strength = high melting point)o Lattice energy comes from the energy of formation of one mole of the compound- Lattice enthalpyo Has a larger negative value for more highly charged ionso The smaller the ions in the lattice, the more negative their enthalpies- Melting points increase with increasing molar mass- KNOW how to interpret a phase diagram!- Molarity (M) = moles of solute moles of solvent - Molality (m) = moles of soluteKg of solvent- When a solution is saturated, no more of the solid placed in the solvent will dissolve, and the concentration of the ions of the solute will not increase- Solubility: the concentration of solute in equilibrium with un-dissolved solute in a saturated solution- Miscible: when liquids mix to an appreciable extent to form a solution- Immiscible: when liquids do not mix to form a solution- Factors that affect solubility: Pressure and Temperatureo With an increase in pressure, more molecules are able to reenter the liquid phase in a given period of timeo Solubility of all gas decrease with increasing temperature- Colligative properties: properties that depend on the relative number of solute and solvent particles in a solution and not their identityo Vapor pressureo Boiling point elevationo Freezing point depressiono Osmotic pressure- True solution: a solution in which the solute does not settle, and solute particles should be in the form of ions or relatively small molecules- Suspension: solute settles to the bottom- Emulsions: colloidal dispersions of one liquid in another- Surfactant: affects the properties of surfaces, and affect the interaction between two phaseso Surfactants use for cleaning are called detergents- Chemical kinetics: a study of the rate of chemical reactions- Reaction mechanism: the detailed pathway taken by atoms and molecules as a reaction proceeds- Rat of reaction = Δconcentration Δtime- The longer after a reaction has begun, the slower the rate will