Cheatography
https://cheatography.com
Important formulas from book covering chapters from chem 121 + 122
This is a draft cheat sheet. It is a work in progress and is not finished yet.
CH 1: ESSENTIALS
density=mass/volume |
°C= 59 ×(°F−32) |
°F= (95×°C) + 32 |
K=°C + 273.15 |
°C= K−273.15 |
CH 5: THERMOCHEMISTRY
q =(c × m × ΔT) = (c × m × (Tfinal−Tinitial)) |
ΔU = q+w |
ΔH∘ reaction = (∑n × ΔHf(products)) −( ∑n × ΔHf(reactants)) |
CH 8: ADV. COVALENT BONDING
bond order = ((number of bonding electron) − (number of antibonding electrons)) / 2 |
CH 10: LIQUIDS AND SOLIDS
h=(2Tcosθ) / (rρg) |
P=Ae−ΔHvap/(RT) |
lnP=−ΔHvap/(RT)+lnA |
ln(P2/P1)= (ΔHvap/R) (1/T1−1/T2) |
nλ=2d sinθ |
CH 11: SOLUTIONS AND COLLOIDS
Cg=kPg |
(PA=(XA) (PA)) |
Psolution=Xsolvent Psolvent |
ΔTb = Kbm |
ΔTf = Kfm |
Π = MRT |
CH 17: ELECTROCHEMISTRY
CH 14: ACID-BASE EQUILIBRIA
Kw = [H3O+][OH−] = 1.0 × 10−14 (at 25 °C) |
pH=−log[H3O+] |
pOH = −log[OH−] |
[H3O+] = 10−pH |
[OH−] = 10−pOH |
pH + pOH = pKw = 14.00 at 25 °C |
Ka=[H3O+][A−] / [HA] |
Kb=[HB+][OH−] / [B] |
Ka × Kb = 1.0 × 10−14 = Kw |
Percent ionization = ( [H3O+]eq / [HA]0 ) ×100 |
pKa = −log Ka |
pKb = −log Kb |
pH= pKa+ log ([A−]/[HA]) |
|
|
CH 2: MOLEC, ATOMS, IONS
average mass= ∑ i (fractional abundance × isotopic mass) i |
CH 6: ELECTRONIC STRUCTURE & PERIODIC PROP
c = λν |
E = hν= hcλ ...where h= 6.626 × 10−34 J s |
1λ = R∞(1/n2(#1) −1n2 |
En=−kZ2 / n2 ...n=1,2,3,… |
ΔE =kZ 2 ( 1/n 2 (#)1 −1/n 2 (#) 2) |
ΔE= kZ2 (1/n2(#1) −1/n2(#2)) |
r= ( n2 /Z) a0 |
CH 9: GASSES
P =F/A |
p = hρg |
p = hρg |
PvTotalv = PvAv + PvBv + PvCv + … = ƩiPi |
PvAv = (XvAv)(PvTotalv) |
XvAv =(nvAv)/ (ntotal) |
rate of diffusion = (amount of gas passing through an area) / (unit of time) |
(rate of effusion of gas A / rate of effusion of gas B) = √mB / √mA =√MB/ √MA |
KEavg =(3/2)(RT) |
CH 12: KINETICS
relative reaction rates for aA⟶bB =(−1/a)(Δ[A]/Δt) =(1/b)(Δ[B]/Δt) |
integrated rate law for zero-order reactions: [A]t=−kt+[A]0 |
half-life for a zero-order reaction t1/2= [A]0/(2k) |
integrated rate law for first-order reactions: ln[A]t=−kt + ln[A]0 |
half-life for a first-order reaction t1/2= ln2/k |
integrated rate law for second-order reactions: 1/[A]t=kt+ 1/[A]0 |
half-life for a second-order reaction t1/2 =1/([A]0k) |
k=Ae−Ea/RT |
lnk= (−Ea/R)(1/T) + lnA |
lnk(1/k2)= (Ea/R) (1/T2−1/T1) |
CH 15: OTHER EQUILIBRIA
MpXq(s)⇌ pMm+(aq)+ qXn−(aq) |
where Ksp=[Mm+]p[Xn−]q |
|
|
CH 3: SUBSTANCE/SOLUTION CONCENTRATION
%X=(massX / mass compound) × 100% |
(molecular or molar mass) / (empirical formula mass)=nformula units/molecule |
(AxBy)n = (Anx)(Bny) |
M=(mol solute) / (L solution) |
(C1)(V1) = (C2)(V2) |
Percent by mass =(mass of solute / mass of solution) ×100 |
ppm = (mass solute) / (mass solution) ×106 ppm |
ppb=(mass solute) / (mass solution) × 109 ppb |
CH 4: STOICH/CHEM. REACTIONS
percent yield = {(actual yield)/(theoretical yield)} ×100 |
CH7: CHEM. BONDING & MOLECULAR GEO.
formal charge = (# valence shell electrons (free atom)) − (# lone pair electrons −(1/2) # bonding electrons) |
Bond energy,diatomic molecule: XY(g)⟶ X(g) + Y(g) DX–Y=ΔH° |
Enthalpy change: ΔH = ƩDbonds broken – ƩDbonds formed |
Lattice energy, solid MX: MX(s)⟶ Mn+(g) +Xn−(g) ΔH^lattice |
Lattice energy, ionic crystal: ΔHlattice = (C(Z+)(Z−)) / Ro |
CH 13: FUNDAMENTAL EQUILIBRIUM CONCEPTS
Qc=[C]c[D]d / [A]a[B]b |
Qp= [PC]c[PD]d / [PA]a[PB]b |
P = MRT |
Kc = Qc at equilibrium |
Kp = Qp at equilibrium |
KP = Kc (RT)Δn |
CH 16: THERMODYNAMICS
ΔS= qrev/T |
S = k ln W |
ΔS=k ln(Wf/Wi) |
ΔS° = ∑νS°(products)−∑νS°(reactants) |
ΔS=qrev/T |
ΔSuniv = ΔSsys + ΔSsurr |
ΔSuniv=ΔSsys+ΔSsurr=ΔSsys+ (qsurr/T) |
ΔG = ΔH − TΔS |
|
