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Convert between F and C (when C = 0, F = 32)
TF = 9/5TC + 32
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Energy of electron jumping
- E relates to Z2/n2, where Z = nuclear charge
- E = constant (1/nf2 - 1/ni2)
- So, jump from higher initial ni = more E, farthest = most energy
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Quantum numners
number of e in a level
- Number of e in an level = 2n2
- First QN = n = average radius, level
- Second QN = l = n-1---> 0
- Third quantum number = ml = +/1 all of l values
- 4ths = ms = spin
- L = shape, 0 = s, 1 = p, 2 = d, 3 = f
- ml = axis in shape, for l = 0, ml = 0 = sphere
- for l = 1, ml = -1, 0, 1 = 3 lobes for p
- Each lobe = 2 electrons
- So, s = 2, p = 6, d = 10
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Z effective, periodic trends
- Zeff = nuclear pull = core e- + protons = 2 + protons so Z effective increases as go right, and decreases down
- EA, IE, EN all increase as you go right and up
- Atomic radius = opposite
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Series for absorption
Photoelectric effect
- To n=2 = Balmer
- To n = 1 = Lyman
- To n = 3 Paschen
- hv (photon) = work + KE
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Radioactive Decay
- Remember charge and mass must match on each side
- Alpha decay = losing helium
- Beta decay = losing electron, so neutron converted to proton
- Positron decay = losing positive electron so proton converted to neutron
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Equilibrium constant
Forward, reverse rate
Keq Change
Qrx
Volume
- Keq = P/R at eq
- forward rate = k1[R], reverse = k2[P]
- So, Keq = k1/k2
- Stoichimetric coeff = exponents
- Keq only changes with temperature, nothing else
- Qrx = P/R at any old time
- Be careful of volume with problems, doesn't always cancel in P/R
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How to solve Keq problem
When to ignore +x and -x
- Always set up as + and -x, solve for Keq
- Note, adding up E components in gas proble
- Ignore x if,
- all reactants and Keq = <10-3
- all products and Keq = >103
- R and P and K = 1
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Complex equilibirum
LeChatleir's
- Happens if product of 1 rxn = reactant of second
- Multiple coeff of 1 rxn so numbers match, and do Keqn to get new Keq for the altered one
- Next to get whole Keq multiply this new Keq x other rxn's Keq
- LeChat; rxn goes back to eq if add or change something. Consider heat, endo exo, moles of gas etc
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Molar solubility
Ksp
Common Ion Effect
- MS = true measure of solubility = max moles per volume
- Ksp = solubility product = [P1][P2]
- Solve like Ice box, +x, -x, but also, coeff = exponents
- x itself = molar solubility
- if question asks for moles dissolved after eq, do n times coeff, b/c x is in solubility/mole
- CIE = like reverse le chatlier's, can represent in ICE box
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Arhenius Acid, B-L, Lewis
Neutral Water, 14
Ka
Kb
Conj pair
- Arhenius A = produces H3O in water
- B-L = proton doner
- Lewis A = lone pair acceptor
- Neutral at 25 C, pH = pOH, 7 = 7
- Ka, larger = higher P/R = better acid
- pka = -log Ka
- Kb, larger = better base
- pkb = -logKb
- For conjugate pair, pKa + pKb = 14
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Strong, weak, very weak acids, bases
Typical strong acids, bases
Haloacid trend
Oxyacid anatomy
- Strong, K>1, pka<0
- Weak, 10-14<K<1, 0<pka<14
- Veryweak, K < 10-14, pka > 14
- Same trend for bases, except, Kb and pKb
- Strong acids = oxacids and haloacids
- Strong bases = carbides (Li-Butyl), amides (Li Dia, NR2), alkoxides, hydrides, hydroxides
- Haloacids, opp of FONClBrISH, I>Br>Cl>F
- Oxyacid, more O, more EN central atom = more acidic
- C.A.Ph.AlcAlpha, 5,10.15.20
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Logarithms
Equation for pH when you know pKa and HA
Equation for pOH when you know pKb and A-
- log (axb) = loga + logb
- log (a/b) = loga - logb
- log 2 = .3
- log 3 = .48
- pH = 1/2pKa - 1/2log[HA]
- pOH = 1/2pKb - 1/2log[A-]
- note, HA or A must be > Ka or Kb
- and pK must be 2<pK<12
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pH and pka
Amino acids
HH equation
- if pH < pKa, protonated, conj acid presides
- if pH > pKa, deprotonated, conj base presides
- AA, C.A., pka = 2-3, so deprot, NH3, pka = 9-10, prot
- if conj a and conjb present
- pH = pKa + log([A]/[HA])
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Buffer range
Recipe for buffer
- Buffer range when A- = HA of conjugate pair
- But also, range in pH = + and -1 from pKa
- Since HH says pH = pKa + log([A]/[HA]), then that means between when A-/HA = 10/1---1/10
- Recipe; 1/2 HA + 1/2A of conj pairs OR
- 1/2 A + 1SA OR 1/2 HA + 1 SB
- SA and SB will react completely, should be unrelated to original acid or base
- Pick HA or A with pka etc near pH you want
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Titrations, SA + SB
pH before titration
pH before eq point
pH at eq point
pH after eq point
- SA + SB, equivalence = when equal moles added = pH 7 aways.
- SA into WB or SB into WA
- if second, when 1/2 equivalent added = buffer, at 1 equivalent, pH > 7 because produce all conjugate base
- opposite for SA into WB
- To find pH of weak acid before titration = 1/2pKa - 1/2log[HA]
- Before eq point, near buffer zone, use HH. At exactly 1/2 eq point, pH = pKa
- At eq point, pH = 1/2(pka + pH titrant)
- After eq point, pH = 14 - pOH, pOH = -log(molarity of SB * each new ml added/total liquid added so far)
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Indicators
- Indicators, H-IND -> H+ + IND-
- Treat like HA and A of buffer
- Color changes at eq point
- pH solution = pKaind +log[Ind/Hind]
- Choose pkA indicator that is + or -1 from equivalence point of acid and base titrating
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Best ideal gas
van der waals gas law
- Best ideal gas = decrease collisions= low P, increase temp so IMF overcome
- (P+an2/V2)(V-nb)=nRT, so Pressure usually less or more depending on repel or attract, and V is usually less
- Usually real gas behaves in a way to fall short of any predictions of Ideal Gas Law
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Avogadro's Law
Boyle's Law
Charle's Law
Partial pressure
liquid pressure
- V/n = V/n
- PV=PV
- V/T = V/T
- PP = mole fraction x total pressure
- LP, difference in heights = density x gravity x change h
- absolute = Patm + pgh
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Gas speed, kinetic energy, trends
root mean squared speed
Diffusion, effusion, iffusion
Isotropic enrichment
- 1/2mv2 = 3/2RT
- Use R as 8.3 if includes speed
- v2/v1 = aqrt(m1/m2) = sqrt(T2/T1)
- rms speed = sqrt (3RT/m)
- lighest gas diffuses fastest
- effusion, gas withmore conc, lighest = fastest
- Can separate isotopes based on weight, lightest effuses first
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