G.Chemistry Theory 1

krabi's version from 2015-09-12 15:53

Section Solution Properties

Question Answer
Which cations always dissolve in H20?Group I ions (Li, Na, K, H+), NH4+
Which anions always dissolveH20? Nitrate (NO3-) CH3COO-, Cl04-
What is always insoluble?Ag, Pb2+, Hg2+ (silver; lead, mercury - Silver Terminator w/lead pipe) CO32- carbonate in limestone buildings, PO43- phosphate in bones; S2- sulfide in eggs. Egging an old building on Halloween w/skeletons
Define Molaritymolute soute per LITRE; is temp dependent; Molar teeth in a Litre measuring cup
Define Molalitysolute per KG for fixed mass solvent; independent of temperature
Mole fractionmole solute /per TOTAL mol
What formula for mixed concentrations?C1V1 = C2V2
Define Colligative PropertiesProperties that vary w/solute concentration (but NOT solute identity)
What are the implications of colligative properties?They extend the liquid range of water eg. anti-freeze which lowers the freezing point
Solute concentration can account for which property?Electrolyte dissassociation regardless of concentration
How to you ID solute concentrationConcentration x Van Hoff Factor
Colligative properties are caused by what?Higher solute concentration ⇒ increases IMF in the solution
Formula for vapour depression?APsolution = [-xP] -x( mole fraction of solute) x P(VP of solvent); Windows -XP in cloud of smoke
Define vapour depressionWhen there is higher ++IMFs ⇒ holds IMF together more tightly
Define Boiling Poiint Elevation++IMF holds on tight ⇒ thus, need to give particles more Energy to leave the solution ie. add salt to water to boil
Formula for Boiling Pt. Elevation?At = kim (constant for given solvent x Van Hoff factor x Molality)
Define Melting and freezing point depression++ increased IMF keeps water lattice from forming
Formula for Melting and freezing point depressionAT = -kim (kim does not like the arctic) (constant for given solvent x Van Hoff factor x Molality)
Osmotic Pressure ElevationHigher concentration is required ++ pressure to RESIST osmosis ie. create drive to move water
Formula for Osmotic pressurePi = iMRT (Van HOff Factor x gas constant x Kelvin); Kelvin ate Pie at the iMRT

Section Kinetic Theory 101

Question Answer
How do you define Kinetics?Rate enzymes, Mechanism, Intermediates, Transition stats and activation Energy
Define ThermodynamicsStability, Equilibrium, Energy, Entropy, Enthalpy, Free energy
Enthalpy isthe amount of heat content used or released in a system at constant pressure. Enthalpy is usually expressed as the change in enthalpy
entropy is a measure of what?In thermodynamics, S is the number of specific ways in which a thermodynamic system may be arranged, commonly understood as a measure of disorder.
Define Activation EnergyDifference between reactant energy and the highest energy of the transition state. AND is the slowest step in the Rate Determining Step. E.g. the baggage holding everyone else back.
How does the Catalyst impact the Activation energy?Catalysts lower the peaks but NOT change the valleys
Define RateChange in the concentration of a reactant or product over time.
Formula for Rate?rR ⇒ pP
Name 6 conditions to change probability of a RX1) Reactants collide w/high concentrations 2) Move faster in solution 3) Lock and key orientation 4) Higher temp gives the minimum energy 5) weaken a bond thru catalyst
How is a Good Tutor like a Catalyst?It gets regenerated; need to know concentration of the constant catalyst


Question Answer
How is a Smart Student an Intermediate?Students are temporary and get used up; can detect and isolate
Difference between transition state and intermediate?Cannot detect and isolate the transition state but ID the intermediate.
Define Rate Laws from MechanismGives the Rate in terms of initial concentration of reactants & rate constant for process; tells me how fast and predicts how fast
Rate FormulaRate = k [R,order] tells me how fast number of particles are colliding in the right orientation.
What are exceptions to the Rate Law?Solids and solvents because they have constant concentration.
What is a condition for a Rate lawRate law is defined by the slowest step which is the rate determining step RDS
define Rate Constantk, roughly equivalent to the probability of a rx, k=Ae (-Ea/RT)
What does the k tell us?Roughly equivalent to the probability of a rx
What is the relationship between K & TDirect correlation (k is fixed)


Question Answer
Define Ionic Solidelectrostatic attraction of cations and anions
Structure of Ionic solid?lattice structure, strong ion bonds
How to ID bond strengthThrough ion charge magnitude & size of Coulomb’s Law
What is the relationship between Charge & Ion attraction?Direct Correlation
Define Network SolidOne big molecule like a diamond, Lattice of covalent bonds where IMF = INTRAmolecular forces
Define Metallic solidsA mango seed of covalent lattice of nuclei & inner shell of electrons, free roaming electrons for conduction
Physical Properties of Metallic Solidsmalleable and ductile but solid at room temperature
Name 3 kinds of IMFs Van der Waals1) Hydrogen bonds w/NOF 2) Dipole-Dipole Forces 3) LDF London Dispersion forces
Define IMFRelatively weak interactions take place between Neutral molecules
Define Ion-DipoleIons attracted to Polar molecules
Define Dipole-DipoleAttraction between positive and negative end (+-) opposite ends attract like in a battery
Define Dipole InducedPermanent dipole induced in a neighboring molecule
Define Instantaneous Dipole Induced Dipoleinstant and temp. Weak and transient interactions between the non polar molecules
Name condictions of Hydrogen Bondingbetween neutral molecules (no ions/dipoles), H w/NOF, covalent plus Lone pairs
What is the strong kind of Dipole-Dipole?H bonding
Define Coulomb LawCoulomb's law states that: The magnitude of the electrostatic force of interaction between 2 point charges ==> is directly proportional to the scalar multiplication of the magnitudes of charges (and inversely proportional to the square of the distance between them.)


Question Answer
Which PT trends go NE?Ionization Energy, Electron Affinity, Electronegativity
Which PT trends go SE?Acidity
Define Resonance Structures1) Octets around all atoms 2) Minimized formal charges 3) -ve charge on electroneg
Define Covalent bondsformed elements of similar electronegativities of 2 non metals
Define Coordinate Covalent bondsforms between a Lewis base (e-donor) & Lewis Acid (e-acceptor)
Ionic bonds form betweenmetals and non-metals due to large electronegativity differences
Why is Ionic bond so strong?strength of bond & Coulomb (larger charges and smaller ions make the strongest ionic bonds)
Non polar bondingmeans equal electron sharing
Polar bonding meansunequal electron sharing w/higher electron density around most E element
VSPR theory isangles between electron groups around the central atom ⇒ maximized for ++ stability
IF bond dipoles are in symmetryTHEN the molecule as a whole is NON POLAR w/London
IF bond dipoles are asymmetricalTHEN molecule with be polar
How are physical changes different then chemical? when no INTRAmolecular bonds are made/broken (just intermolecular forces between atoms/molecules)
Define Phase Transitionare physical changes due to temperature.
What impacts phase transition?Average KE of molecules (temp) affects its phase. KE ⇒ to Entropy.
What are the physical properties of solids?Least KE, most ordered, when enuf KE is absorbed it turns into liquid
What as the most KE and entropy?Gases
What is the KE of liquids?Has enuf KE to escape fixed position; more entropy than solids