S1 Fall Exam

UNIT 1 - ATOMIC STRUCTURE & PROPERTIES

  • isotope - same protons and electrons but diff. neutrons » diff. mass

photoelectric effect: high enough energy » ejection

* max e- in main energy levels is 2n²

energy lvl » sublvl » orbital

aufbau exceptions: d & f “borrow”

  • isoelectronic - same e- configuration

binding E: hν - KE

F α q1q2/r²

IE ^>; +E is endothermic

EN ^> F***; no noble gases

EA ^>; -E is exothermic

AR v<

IR: least protons is the largest when they are isoelectronic

D-block: 2 valence e-

FORMULAS

avg. atomic mass = ∑(% each)(mass each)/100

percent mass = (mass element)/(molar mass) *100

UNIT 2 - MOLECULAR & IONIC COMPOUNDS

covalent bonds based on EN (so noble gases excluded)

  • nonpolar covalent: two of same OR C&H

  • polar covalent: dipoles w/ partial charges

  • ionic: M + NM

as atoms approach, potential E decreases; but too close leads to repulsion between nuclei

  • happy medium: min. potential E

inverse rls between bond length and E

larger AR » long, weak bond; smaller AR » short, strong bond

(ionic): charges, distance - coulomb’s law

ionic lattice structure - high MP&BP, low volatility&VP, brittle, conduct when aq.

*presence of H2O implied in dissolving equation

covalent IMFs - low MP&BP

  • interstitial alloy: smaller atoms fill spaces

  • substitutional alloy: replacement with other atoms (EX: sterling silver, rose gold)

(N - A)/2 = S

*H & F are never central atoms (least EN)

expanded octets start from 3d orbital

incomplete octets are usually Be or B

  • isomers: same molecular formula, diff. arrangment (EX: pentane, isopentane, neopentane as C5H12)

overall dipole moments go to most EN

sum of formal charges is total charge of polyatomic ion

lowest formal charges & (-) charges on most EN

  • cis isomers: same sides of double bond

  • trans isomers: diff. sides of double bond

*diff. conformations are not isomers

FORMULAS

formal charge = (neutral atom # of e-) - (central atom # of valence e-)

UNIT 3 PART 1 - IMFs & PROPERTIES

LD » DiD » DD» HB » ID » IB

  • LD: instantaneous dipole = induced/polarized dipole (“atomic peer pressure”)

polarizability - **e-, *SA

(EX: I2, high sublimation point)

  • ID: **charge, *AR

  • HB: N,O,F lone pair to H+

**↑BP, ↓VP

covalent network solids - diamond & graphite (allotropes), silicon dioxide, silicon carbide/quartz

diamond- tetrahedral; high MP&BP

graphite - trigonal planar 2D plane; high MP; single-plane conduction

molecular solids - low MP, nonconductive (EX: I2)

solUTE dissolves in solVENT

  • chromatography - stationary and mobile phases

  • eluent - fluid entering

  • eluate - fluid exiting

  • elution - process of moving compund using solvent

FORMULAS

Rf = (mixture component distance traveled)/(solvent distance traveled)

UNIT 3 PART 2 - GASES & SOLUTIONS

↑P↑T; ↑V↑T; ↑P↓V

(STP): 1 mol (g) = 22.4 L

  • effusion - gas escaping through small opening

  • diffusion - homogenous mixture formed through mixing of two diff. gases

  • urms = sqrt[3RT/MM]

KMT: gas particles (1) are spherical, (2) move in straight lines, (3) have no volume, (4) have no IMFs, (5) undergo perfectly elastic collisions, KE conserved

avg. KE dependent on K temp. ONLY

KE = ½MMv²

distribution graphs should consist of same areas

deviation: high P, low T

  • endothermic - breaking bonds

  • exothermic - forming bonds

  • enthalpy - heat of solution (△H)

UV & visible - short λ, high E

IR - intermediate λ, E

microwave - long λ, low E

low absorption = higher reflection

FORMULAS

PV = nRT (atm L mol⁻¹ K⁻¹)

Pa = Ptotal*Xa

Xa = (mol A)(total mol gas)

(rate effusion A)/(rate effusion B) = sqrt[(MM B)/(MM A)]

A = εbc

(absorbance) = (molar absorptivity)(path length)(concentration)

UNIT 4 - CHEMICAL REACTIONS

separating physical components - chromatography, filtration, distillation

combustion: hydrocarbon + O2 → CO2 +H2O

**subscript H/2: even is coeff. 1, odd is coeff. 2

strong solubility: SNAP, So I CLearly BRought NO CLean CLothes, G1&2 metal hydroxides

  • titrant - from burette, known M & V

  • titrand/analyte - into flask, known V, unknown M

acids lose H+; bases gain H+

  • amphoteric - both acid and base

LEO, GER

(oxidation #s)

pure element: 0

monatomic ion: charge

F: -1

O: -2

O w/ F: +1, +2

O w/ perioxide: -1

H: +1, -1

G1: +1, G2: +2

Al: +3

FORMULAS

percent yield = (actual)/(theoretical)

UNIT 5 - KINETICS

collision theory criteria:

  1. reactant particles must collide

  2. Ea met

  3. correct molecular orientation

increasing reaction rate: increasing concentration, SA, temp. or adding catalyst

△H does not affect reaction rate

unimolecular (fastest) » bimolecular » termolecular (slowest)

  • rate-determining step - slowest, highest-reaching potential energy

intermediate: ○»●——●»○

catalyst: ●»○——○»●

**neither present in overall reactions

rate law determined from reaction mechanism and/or experimental data

**no intermediates in final rate law

  • zero order: linear, constant rate

  • first order: constant half-life

  • second order: exponential

FORMULAS

rate = △M/△s

rate = k[A][B][C]

zero order lin: [A]t - [A]₀ = -kt

first order lin: ln[A]t - ln[A]₀ = -kt

second order lin: 1/[A]t - 1/[A]₀ = kt

t½ = ln2/k