Question | Answer |
Dipole-Dipole Bonding | occurs between polar molecules; (+) end of 1 molecule is attracted to the (-) end of another molecule; 1-2% of the strength of an ionic bond; larger molecule = higher boiling point |
Hydrogen Bonding | special type of dipole-dipole (stronger than regular); between hydrogen and "highly electronegative elements" (usually F, N, O); larger molecule = higher boiling point |
London Dispersion Forces | occurs between nonpolar molecules; size of molecule and strength of force are directionally proportional (larger molecule= higher boiling point) |
Surface Tension | resistance of liquid to increase its surface area; large intermolecular forces = high surface tension |
Capillary Action | the spontaneous rising of a liquid in a narrow tube (forming meniscus); when substance is polar, meniscus is concave, when substance is nonpolar, its convex |
Cohesive Forces | forces among the molecules that can cause capillary action |
Adhesive Forces | forces between the molecules and the container that can cause capillary action |
Viscosity | measure of a liquid's resistance to flow; large intermolecular forces = highly viscous |
Crystalline Solids | solids with a highly regular arrangement of their components |
Amorphous Solids | solids with considerable disorder in their structures |
Ionic Solids | type of crystalline solid; ions are at the points of the lattice |
Molecular Solids | type of cyrstalline solid; have covalently bonded molecules at each lattice point |
Atomic Solids | type of crystalline solid; have atoms at the lattice points |
Metallic Solids | subgroup of atomic solids; a special type of delocalized nondirectiona covalent bonding occurs |
Network Solids | subgroup of atomic solids; atoms bond to each other with strong directional covalent bonds that lead to networks of other atoms |
Group 8A Solids | subgroup of atomic solids; noble gases are attracted to each other with weak London dispersion forces |
Hydration | process by which ionic substances dissociate into ions. cations are attracted to the (-) end of H2O (O) and anions are attracted to the (+) end (H2) |
Properties of Electrolytes | dissociate in solution; solution conducts electricity |
Strong Electrolytes | completely dissociate in H2O |
Weak Electrolytes | dissociate to a small degree in H2O |
Non-Electrolytes | may dissolve in H2O, but do not dissociate at all |
Strong Acids | HCl, H2SO4, HNO3, HClO4, HBr, HI |
Strong Bases | NaOH, KOH, LiOH, Ca(OH)2, Sr(OH)2, Ba(OH)2 |
Weak Acids | HC2H3O2, H3PO4, HNO2, HOCl, C6H5COOH |
Weak Bases | NH3 |
Molarity | moles of solute / liters of solution |
Molality | moles of solute / kg of solvent |
Mole Fraction | moles of solute / moles of solution |
Mass Percent | ( g solute / g solution ) x 100 |
Acids | releases H+ into solution; proton donor; electron acceptor |
Bases | releases OH- into solution; proton acceptor; electron donor |
Properties of Acids | dissociate into ions in solution; solution conducts electricity; low pH (below 7); litmus turns red; phenolphthalein remains colorless; if reacted w/ active metal, produces H2 gas; if reacted with carbonates, will form CO2 |
Equilibrium | equal rates of reaction; lies far to the right for strong acids, far to the left for weak acids |
Ka | equilibrium expression; [concentration of products] / [concentration of reactants] |
Amphoteric | can act as both an acid and as a base, e.g., water |
Evaporation | the process by which molecules go from liquid to gaseous state; endothermic because gas has more energy than liquid, so energy must go into the system |
Boiling | gas is able to come up from the bottom; occurs throughout entire liquid |
Vapor Pressure | ability of molecules to enter vapor stage |
Boiling Point | temperature at which vapor pressure of liquid is equal to the atmospheric pressure |
Normal Boiling Point | temperature at which the vapor pressure of the liquid is equal to the normal atomospheric pressure |
Temperature | a measure of the average kinetic energy |
Relationship Between Temperature and Vapor Pressure | as temperature increases, energy of molecules increase. higher energy means less energy has to be added to become gaseous, so it is easier to become gaseous. higher ability to become gaseous = higher vapor pressure.as temp increases so does vapor pressure |
Why does evaporation lower a liquid's temperature? | evaporation is endothermic, so energy enters the system and increases the molecules' energy. the energetic molecules evaporate, leaving low-energy molecules (not enough energy to become gas). lower energy is reflected in a lower temperature. |
Melting Point | point where the liquid and solid have identical vapor pressures |
Normal Melting Point | temperature at which the solid and liquid states have the same vapor pressure under conditions where the total pressure is one atmosphere |
Raolt's Law (Vapor Pressure of Solution Formula) | P(soln) = X(solv)P(solv) (vapor pressure of solution = (mole fraction of solvent)(vapor pressure of pure solvent) |
Sublimation | process by which molecules of a solid become gaseous without passing through the liquid state |
Colloids | suspension of tiny particles in some medium; particles are single large molecules or aggreates of molecules/ions; also called colloidal dispersions |
Tyndall Effect | suspended particles scatter light, making the beam of light visible from the side; can be used to distinguish between a suspension and a true solution |
Coagulation | destruction of a colloid; can be caused by heating or adding an electrolyte |
Van't Hoff Factor (i) | i = ( moles of particles in solution / moles of solute dissolved ); number of particles a substance dissociates into when in solution |
Ion Pairing | some ions remain paired instead of dissociating; leads to deviation from expected value of "i" |
Osmotic Pressure (formula) | osmotic pressure = iMRT |
Gas Law Constant (R) | 0.0826 |
Change in Freezing Point (formula) | Tf = imTf ; Tf = temperature of pure solvent in K |
Change in Boiling Point | Tb = imTb ; Tb = boiling point of pure solvent in K |
Triple Point | only point at which all three phases can coexist |
Critical Point | end of the line between vapor and liquid phases; shows the critical temperature and critical pressure |
Critical Temperature | highest temperature at which vapor can be liquified |
Critical Pressure | the pressure needed to liquify vapor at the critical temperature |
Ion Dipole | ionic bonding; occurs between two polar ionic molecules; strongest type of intermolecular bond |
Mixture | two or more elements physically sharing the same space; the elements' appearances may change, but their chemical properties won't; a mixture can be separated into its component parts with relative ease |
Compound | two or more elements chemically combined; a new substance is formed and the individual elements lose their original properties |
Homogenous | consistent throughout; components are evenly dispersed |
Solution | a homogenous mixture |
Solubility | the ability to dissolve |
Temperature's Effect on Solubility | increases solubililty in solids and liquids; decreases solubility in gases |
Pressure's Effect on Solubility | increases solubility in gases; no effect in solids/liquids |
Why is it beneficial to have measures of concentration that are Temperature Independent? | temperature affects volume, but not mass. molality, mole fraction, & mass percent are mass-based, but molarity is volume-based. M of a solution may change as the temp. changes, but m, x, and m% won't change |
Explain nature of solute and solvent in relation to (delta)T. | (delta)T doesn't depend on the nature of the solute, just on the number of solute particles (i); it does however depend on the nature of the solvent, because Kb and Kf are specific to each individual solvent. |
Colligative Properties | properties that change when a solute dissolves in a solvent; vapor pressure, osmotic pressure, freezing point, boiling point |
Enthalpy of Vaporization | (delta)Hvap; energy required to vaporize one mole of molecules at standard atmospheric pressure |
Enthalpy of Fusion | (delta)Hfus; energy required to melt one mole of molecules at standard atmospheric pressure |
Conjugate Base | everything that remains of the acid molecule after a proton is lost |
Conjugate Acid | formed when the proton is transferred to the base; essentially base + H+ |
Conjugate Acid-Base Pair | two substances related to each other by the donating and accepting of a single proton; two substances that differ only by the presence or lack of H+; e.g., acid and conjugate base |
Acid-Base Reaction | H+ and OH- combine to form H2O; also called neutralization reaction; enough base is added to react exactly with the acid in a solution |
Precipitation Reaction | a reaction in which an insoluble substance forms and separates from the solution |
Oxidation-Reduction (Redox) Reaction | a reaction in which one or more electrons are transferred |
Equivalence Point | point in titration where enough titrant has been added to neutralize the base |
Endpoint | point where indicator changes color |