g in § equilibrium ·'T." ~ "apor pressul-e: Thc " partial pressure of the :2 gas in equilibrium,t with liquid depends on temperature: equals I atm at "Th ." HINTS FOR BALANCING EQUATI
Trang 1, -.- d -subshell
=
1 01
N
I
*x
=
,.
II K Sc Ti V Cr Mn Fe Co NI Cu Zn Go Ge As Se Br d:< .y
39.10 37 4.08 44.96 38 3' 47.88 40 50.94 5200 54.94 41 42 43 55.85 58.93 58.69 63.55 45 , 65.39 At 69.72 4' 72.61 SO 74.92 78.96 7951 52 90 53 83.80 54 - , (}
y' - O -""
Of
=
85 47 8762 88.91 9122 92.91 95.94 97.91 101.07 102.91 106.42 107.87 12.41 114.82 118.71 121.75
23
132.91 137.32 138.91 178.49 180.95 183.85 186.21 19020 192.22 19508 196.97 200.59 204.38 207.20 208.98 208.98 20999 222.02
87 8& 89 104 lOS 106 107 108 109 110 111 112 113 114 115 110 117 118
30
90 91 92 '3 94 95 '0 97 98 100 101 102 103 v. _
Th Po U Np Pu Am Cm Bk Cf Es Fm Md No lr Y~r·
23204 231.04 238.05 23705 24406 243.06 247CJ1 24707 251 =al 25710 25810 2&1.10 WIll s
ATOMIC STRUCTURE
Atomk Number, Z: # or protons in the nucleus:
atom Z = # oreleclrol1S; lor all ion ol'charge -q Z fq cleclron n: principle L: angular momentum (orbital shape)
for calion of charge +q Z-q electrons Mass Number,A: A= Z + N m,: magnetic (orb al irection) m.: ciectro
the number of ncutrons in the nucleus Isotupes: Atol11s with the For each 11 the possible 1 values arc O I n-l; lor each I the po s
same Z, dinerent A An clement can have a !lumber or isotopes; any m, values arc - I .0 +/ : n\ has two possible value : + II a n d - '/ , (spi
up spin down) Each value orn den tes a "shell" in e alomic slruc
sample contains a number of isotopes; in practical work, lise the
ture: each I denotes a subshcl
isotopes Ii)r a given element) s-orbital: I =0 I type p-urbital: 1= 1 3
60 \Id I\! l! Od \' 1l111 1 111
Nuclear reactions alter the nucleus: part ides ejected or absorbed Aufbau order for filling sublevels 1>4 l id Ciadliliniuril
lor Ihe hydrogen atom are used to
describe all many-electron atoms 66 Dy J) ys pn)~iurn il,lIows Ihe Einstein Equatiun: E = mc' and io s A more rigorous trcat- ~ , r J/, I 4.J 1 67 Iii, Iltllmium
menl cielermines exact energy lev-~JiU}t~" 3., I 41' ~ ~ I 5{ 69 Tm ItlX,lJ Thlililllll
71 Lli 175.11 Lulclillill
Types uf processes: ''',,'' i, ,,, ,"b~ ,' "Il , " , ,, d;IT,,,"' '""' ~ ~ , ml n I II" 17X" l1alili mll Transmutatiun: New clements made li'om particle collisions gics The filling or levels is guided by the i 7 r 7.1 Ta IX1l ~ Tanl allll ll
Fusion (small atol11s combine): H-I + H-2 -> He-3 Aufbau Principle: 7, 74 W IUS T Ull g si 11
7 R 1 8 ~ /{h i: l1IUIl1
0 0 + II, H Is-orbital 7Y Au \9 7.0 (.uld Radioactive decay: [ First ton,zation Potential vs Z [
XO Ilg 2UI).6 Nlcn.:ur y
! 25 t'H-fe" -""""CC 2 0 0 + II Li 2s-orbital r'b 207.2 Lead
~ 2 0 tft _~ N ~ e-~ - 2 0 0 ' /, Be spherical J1i 2 Y Ui~mul11
U-23S ==> a -I Th-234
'Ydeca)' (photon): Accompanied c: 10r1~-+_r~ A<~ 2 +1 + 'I, N
'~ 5 j-.JL c1F -clIC= = - ' I
P 'c 0 ' - - -
electron configuration: Atomic orbital occupancy [ Electroneativity vs Z Atomic Radius vs Z Pauli Exclusion Principle: Each electron has a unique sct or quan
tum #s An orbital may hold up to two electrons one with spin-up
3 In = + 1/: and one with spin-do\'.ll m = -I/::
~~ ~ ul50~~~~-~ -~ H~nd's Rule: Electrons rill p d and f sub-shclls in a manner to max
imize the number of unpaired electrons (hal l~rilkd orbilals)
5 2 ';; '" loo t- t = "' ' ' ' ' - - - -=
ionizatiun potential (IP): Energy required 10 remove cieCiron
:;: 0 l _ _ _ _ _ _ _ an atol11 or ion First IP: Removal or rirst valence electron
iIi
00 5 to t5 2025 30 3540 o 5 10 15 2025 30 35 electronegativity: Tendency or an atom to al1rael electrons in a
Atomic Number Atomic Number chemical bond; 0-4 scale 0 1'01' rare
1
Trang 2formation: Elements to compound; C + 2 H, =>
combination (synthesis): 2 substances ">rIn a
-2 Na + CI, => 2
ox
(s
(sec expanded se
decomposition: I substance yields 2 or more subs
2 HgO => 2 fig +
displacement: Elcnlent displaces
compound; Zn , 2 HCI => H, + Znel,
double displacement or metathesis: F:xchangc anions
precipitate: NaCI (aq) + AgNO,(aq) => AgCI(ppt) f NaNO,
combustion: Exothermic reaeiion with oxygen: C + 0 => CO ,
PHYSICAL PROCESSES
melting (s => I): (j'eczin (I => s)
(at I atm normalmclting point "T "
evaporating (I > g)~ condensation (g => I) III
(at 1 all11, normal boiling point "T,,"')
sublimation (s =>
solution formation = mixing 01' gases
distilla
mixture hy slective
Liquid
triple point:·s I g in §
equilibrium ·'T." ~
"apor pressul-e: Thc "
partial pressure of the :2
gas in equilibrium,t
with liquid (depends
on temperature):
equals I atm at "Th "
HINTS FOR BALANCING
EQUATIONS
Find the whole-number coefficients which give the same
amount or each e(cment on each side of the equation
Identify e ch element involved in the reactio
Change eoelTicients only not the f
Apply coclTicicnts to e h atom in a polyatomi
Determine th net charge lor each side of the equa
Must be balanced in the
Start with the element appearing once on each side
Next focLls nn the more complex compounds
II' an element appears in a pure form, leave it to the last ste
It may help to use fractions to balance the
integer coefficients n!'ter all elements arc balance
Final step make sure c(Je lTicients are the smalles
numbers
Remember: Always chee, your work I Make SLlre that the
same number of cach type ofatom and the same total charge
are on e ch side of the equation
NOMENCLATURE
Chemical
Stan with the "cation" name
1l,lIowed by "anion": use
fixes to a
from clement na
Organic: Separate naming sys
~-('2' - - • " ,
Chemical Formulae Cation symbol followcd by anion
Subscripts denote relative composition
Enclose polyatomic ions or molecules in parentheses
Mol~cular Formula: Discrete molecule
Empirical Formula: Relative molar ratio of elements for solids or molecules
Transition metal: Valence varies, give the va are less confusing
ferric Fe (III)
stannic Sn (IV) stannous, plumbic Pb (IV)
cupric eu (II) cuprous mercuric Hg (II) mercurous
ammonium, NH +
hydronium H,O+; active f(lI'Ill ofacid in water
@ carbide C silicide
@ nitride N .1' phosphide P ]' arsenide, As
@ oxide ° ' - sulfide S " selenide Se 1- telluride Tc
8) hydride H halides: fluoride F' chloride CI ' Br~ iodide I Acids: hydro -fiuoric, - chloric ·bromic -iodie Polyatomic anions (& respective acids)
8) acetate, C,HP', aceti c a id, C,H,O
nitrate NO.; nitrite NO, nitmlls acid
hypochloritc ClO inpach/ul'Olis acid, H
chlorite CIO,' chloroll s
perchlorate ClO; perch/oric a c id , HC/O
hydroxide OH' ./i)rmed h.\' has e
bicarhonate or hydrogen carbonate, H C
bisulfate or hydrogen sull' permanganate M
@ carbonate cot carhoni c acid, fi, C
sulfate, SO," SII/fill'i c ocid, if, S
sulfite, SO, , s lI/fimJl(s {/cid
chromate CrO, , chmlllic acid,
peroxide 0, biphosphatc or hydrogen phosphate HPO/' dichromate Cr,07 , thiosulfate s ,ot(thio: S subsl tor 0 atom) disulfide
-phosphate, po ," p/IO 'phori c acid, H,PO,
@ silicate SiO, ,~ ,i/icic uc id H,SiO,
Reaction equation i ~ a molecular equation; the maSses or individualmokcules are too small for routine us The mole (Avogadro's number or atoms particles or molecules) gives
a morc usable quantity
The molar mass of a material is the mass (in grams) of I mole of the material (the formula weight or molecular weight) It is determined by summing the atomic weights
lor the ements comprising thc material, weighted by the I'ormula coefficients (e.g I mille of c rbon-12 is 1.0
The balanced molar equation can alsll be vie
anced molecular equation with the coen-icicnts inte
as molar qua theoretical yield: Mass of pro ucts is determined fro
mass of re ctants molar mass and balanced equati
limiting reagents: For two or more reactants the OIlL' co
sumed first will limit the amount solution calculation: Number of moles = solution (in liters) x the molarity (moles per liter) of the reag
2
MEASUREMENT Be UNITS
rnass: Kilug ramlkg) = 1,000 g 2.2tJ46 pound I~ngth: Meter (111) = ItJO em - l.tJ936 yard = 10'" A
time: Second ( ); temperature: Kelvin (K)
T(K) =T("C)+ 273.15 T(,'F) = "I" T ("C) 32
Boiling water _ mJ: _ _ _ j.QQ"j:';- - -· 373 K Body
temp
Room temp
-310 K
-293 K Freezing
water
_~;;> : c_ _ _ _ O : C _ _ _ _ _
-273 K
volume: I iter (l) = 1.0110111 L - 1.0567 quart
pressure: Pascal Pa ( N / I11 " ) : atm - 101.325 I'a
force: 'lewton, N (JIm); chargc: c·Qulomb l'
energ : Ioule • 1 (kg 111'/s) = 0.~3901 ca lo e
Prefixes tera T (1012) ~iga (; ( j(J") mega M ( 1"
kilo k (10' ) centi c (1 0 ") millim(I() '
micro ~I ( Itt", nano n (10-") "ico p (1 0'''
R = R.J I4.1 n1Ole" K ' (Io rencrgy calculatio )
R = 0.082 I atm mole" K ' ( for g s pr"pert ealclliatinn)
Avogadro'S Numher: N, 6.021 x 10" mole " Boltzmann constant: k R f N, U RI , In " J Illolcl'ulc-' K·'
Elementary charg" of the el,'ctron e: 1,(,02 x I(J ,,' C
Faraday Constant I : c h"r~ c of N c!cctruns
Mass of a proton m : 1.6 3, 10 ," k
Mass of a neutron, m,,: 1.675 \ III 27 k Mass of an electron m : 9.110 \ 10 " h!
Planck's Constant, h: (~.62(, x 10" I s Speed of light in a vacuum, c: 2.9 97 ~ \ Ill' m s·
CHEMICAL INTERACTIONS
A Electronic Properties:
sity relative to the cenll:r ~ )r l1la~s: imparts partial l:hargc to
thc molecule: /1= 0 for symmetric (II,)
, > for asymnu'tric:
O + H _ Cl e polarizability: Tcndclll:y ofl:h:clron c10UlJ to distol1 fmm equi librium due to ternal ckc lro ~ tali cs : inl'reaSl'S with atom size
B Intermolecular (betwe n molecules)
London Forces (DiSCrsion): t\t1radion or Induced-dipole
tnO T1l em~ ; stronge fllr ll1C.wc polarl/ub1c ~pc cie s: nCl!OU nb
1;:'11' liquc:faction of g<J ";t.:s like argon ti nd m~th a nc
dipole-dipolc: Molectllcs wilh Jipolc 11i01 Jle.Jlb CXl'K!ri cl lI':c ~t trnc li\c forces for ccnain rdlli\c o ri~ n tntio n :{ 13ascL1 O ~k-eL r (i ~ wtir : fu rcc~
s+ stable S- S+ 1' less st0+ o· Sab' 0+le hydrugcn -bond in~ : E n n t.:~J u ip o l (.;-i ll t~r; l t: tion hctw""""ll h ro
gl.!l1 (iran -011 or -Ni r(Jt!p arid a Ilc.:alt)y oxyg~lll ) r nitrogenatolll
cl('ctrostatic: trong intc.:ral:lion lX'h\ il.'l.'i l iuns: allra~ l i\'\ ~ (oppn
~itc c h arg~:t;) or rcpulsiv(' (/ (: I.:hargc.:s) Imcr"ldy prop\lrtivn:ll
to d i ~tan cc and dielectric ~{)list n nt of iht! llll.'diUTll Wakr h~l 3
C Chemical onds ( bet,, ~~ n atoms in llIo l ~cu l es)
valence electro : The o ter det:toll:-; \\ hich form thc mi c l bonds The rl.!: l of !hc clcdrons (inIH.:r- hL"ll) flrC 111l:rI curl' electrons Bonding is described with three ideal modek covalen bond: lcct r on~ an: shared: the pohtriy of th ~
ionic bond: I- Ic:ctrustatic inlcr,l( tiutls iJct\\ \ 'i.:1l ion:-::i.:reat",'ll by the U UllS
ter ofelectronsbcrvvecn atom , to create! kIllS \\ ilh fil led \ ·mx· : hell
metallic bond: Electron, arc doloc"li7c(1: Shored by n large
numb!.!r ofmdnlJic nuc":i
real bonds: P:\rtially conkntlpartially ionic Dil1l:I"(,JlcC in
ch.!clroncgativity dClcnnlllCS the t~ ' D i\lllic L"ilar;ll :tcr
Io ic Cha racter I
::::;:= '!zzTf¥
0.5 1 1.5 2 2.5 3 3.5 Electronegativy difference
Trang 3FORMAL BONDING MODELS
H:H : ¢I : 9.1: g::g
H : 9.1:
4 bonds (exccpt H, which will have 2 electrons, and
atoms with d-orbitals, which cn form 6 bonds e.g SF,,)
multiple IKlnds: Bonded atoms may share 1,2 or 3 electron pairs
number of neighbors Single bond (order 1.0) double
triple (3.0), may be fractional For
rL'sonance: If dillcrcnt Le\vis structures
electrons, relative to the li'ee atol11 Calculated as t(lilows: (#
of valence electrons in li'ce atom) - /, (# bonded electrons)
(# lone pair electrons ) Other things equal: Structures with
smaller formal charges arc morc stable, place negative charge
" -= _~ _ = = - _ _ _ -= _ _ _ ~_ o: -
BF3 ~I=O Hybrid=sp2
NH3
AX2E2
H2O
T-s haped
AXl2
I 13
AX2E3
ICI2-AXSF 6 oct~I=O ahedral Hybrid=sp3d2 •
S, p, d and f AOs can mix or hybridize to form equiv
alent lone p irs and bonding pairs orbitals Supports
VS EPR model S and p can h bridi Le to sp (2), Spl (3)
or sp' (4 equivalent orbilal,); d orbitab expand the
options to five (sp'<l) and six bonded neighbors (spJd)
+
+ 2p,
Geometry: Valence Shell Electron Pair Repulsion
Particle-Wave Duality: Electrons and lighl exhibit waw and par
ticle character The wavelength (A) of light desclibes the "color,"
related to the fj'cqucncy (v) and spced of light (e), by AV ~ c: th
energy of light is quantized in photons, hv (h, Planck's Constant)
In simple form, the electron wave-property is described by the deBrUJllic mooel: the A is related to its mass (m) and velocity (v)
by A= h/mv Eleclrons in atoms occupy discrete energy levels and are described with quantum numbers and wavelike atomic orbitals (AOs) The Autbau principle guides the tilling or Ihe atomic energy levels The complete description ofthe wave char
acter is termed the wavefunction 1jf The AOs give IjI lor an atom
MOs give the IjI tor a molecule; each MO is a
enee: A less stable
8 1 a '~
~
rr
a: ofT ax is arc termed
rr Antibolllling inter
actions arc notL'd IT
and G'
density in the bonding region
for electrons in the molecule As for
BEHAVIOR OF GASES
P: Pressure is the force/area exerted on the container walls (in atm, mm IIg, Pal V: Volume of the gas sample (in liters)
273.15 K one molc ortdeal Gas occupies 22.414 liter
Bovle's Law: P x V is a constant lor fixed T: p ~
-1
~o
:J O
>0
Gas is 3/2 RT; the velocity (rms) for a gas with
"M" at a given T is (3RT/M)' (the average speed of
expands into a vacuum); also fits diffusion j()r low P
3
• Gases liyucfy at low r and high P_
• Mulcclill's haVl' rotational anti vibr.l liuna energy
adds terms t~'r 1l1l1]ecuiar volume and inlcnnl)lcl'uiar n tt rn('ti(m~
MIXTURES 8& SOLUTIONS
Phvsical cmbination: Solule (,ulid or les 'cr amount) dis sol~es In the solvent (liquid or i3rger amount)
more disordered than ,cparate pha,cs
Variable Factor: Interaction between materials "I ike-dissohCs
liI,c"; polar materials mi'l (miscible), u.s do nonpolar Pular and
nonpolar arc usually immiscible (furm sepanlte liquid la)cn»
Solution unils:
M: Molarity -moles of solute cii"olved in I lilcroi'soluuon
Ill: Molalit) - l110les of solute per kg or soh en!
x: Mole fraclion -1110le of solute divided by tMal l11ules
colligative propel·ties: Dep nd o ly 0 11 the llul11ocrot'solute par ticles lind the identity of the solvent Ionic matelinls tlis"x:iatc
vapor pressure lowering:
feezing pt dc pr es~io n :
.1.T= -m 111.:k rp (con~tal11 depl'nds on "iu!n:nt)
boili ng pt, elevalion
Il.T= m"",,,k hr (constunt dep nd
osm
n M~(/ltU~ RT R is the Ideal ,as constal1l; account\ f'
gor pressure in rlunts and ' hapc
oxidation #: Element (0), ionic substance
io , covalent compound (charge on atom if all
electrons shi n to the more electonegat
redox chemistry: I.kctr(lils arc exchallged in the reaction
View rection "A +B A " in two stcjls (half-reliction,) t'irst oxidation: (A loses elcctrons! A ~
thell reduction (B gaills electn",,), l3 +e
-A + B I(lnll th e pmtluct
Balancinl( Redox Reactions: Tvv" eOl11lllon approuehes:
I lJalr-Reaclion ~I c thod : IJalance Ihe reduction and o.\ida lion "hal r L'Ul:llon:,:' ClHllhillC \\ it h electron l1(m halalll:t.!J
o Oxid:lHnn-Number Method: I~e lily change, In elements
\ ll.!ncl!: hillnt.:\! C k C ln)J)- c\t h ang~
Foracidlc: Usc II () anJ II ,0 II ) hakJl1cc For Ixt"ie: lisc Oil aJ1~ fLO
Examples of redo\ reactio battcry/gahanie: n(s) ~Cu (a'l ) > Ln' laq) +
electrolySis 2 110 () 2 II, (g) 0 , (g)
c rrosion: 2 AI (s) 30'(g) ·
dectrochemical cell: An external CirCUit
tmdes (anode - ,itc uf Ll\idalo anti cathode
reduction) 10 facilitate the reactio
cell EMF: Electrical potential generated by the cell: f >
for spontall!.!Ou:,
galvanic (vo llaic): pontancolls reation produces a nO\\
current; u,;ed to make batt
Diagram for Zn eu cll: n(s) IZn' (aq) II ClI' (aq) I(lI(sl
Trang 4electrolytic: Exte:nal currentivolt- Electrolysis of molten NaCI
age drives the reaction
powered electrolytic process
For E < 0, reverse
neous AG = -n Jt ( 7, Farad
constant, "n" mol es or elec
trons); reverse' a tion, ch
th sign of the
Standard poten
EY :::: Etlan",!.: + EO (.';!lhm J,:
Reduction poten
tials: Standard tab
ulation of electrod
half-rea tions (writ- 2 CI-(I~ CI2(g)+2e- 2 Na+(I)+2e 2Na(l)
ten as reduction)
Reference potential: H, electrode O OU V
o Non metals: E, + 2 e~ => 2 E-
A larger, positive numher is evidence ofa more reactive materiaL
Fo 2.87 I, 1.36 Br, 1.09 1 54
o Metals: M ' (aq) + x e-=> Metal
The positive value is evidence of a less-reactive metal
Ag(l) + 0.80 Cu(ll) + 0.3 Pb(") -0.13 Ni(ll) -0.26 Fe(II) -0.45
Zn -0.76 AI-I 6 Mg -2.37 Na -2.71 Li -3.04
Aqueous Solubility:
acdatt: chlori(it: fluoride sulfate carbonate oxide
nitrate bromid : sulfide
chromate
i.iJl1lll0n iUlll rSOlu ~ ~e ide
Ca Mg s insol inso
Sr Sa insol insol inso
rc, Cu Zn Insol s ins-ol
P(ll) lIlso1 Illsol insol insol
Ag Illso1 insoi ins
Chara
violet: potassium, rubidium,
green: copper (emerald), barium (yellowish) zinc
yellow: sod
red: lithium (carmine), strontium (seariet), calcium (yellowis
ACID-BASE REACTIONS
Self-ionization or water: H10 <=> OW + HJO
K" = 1011-IIH,o' 1 = Ixlo- I' at 25"e For all aqueous
Neutral solution 10H-1= IH,O+I =
IxIO-pH = -loglII[H,O'I: A measure of acidic strength:
solutions, pH = 7; acidic, pH < 7; basic, p H > 7 (eg a
M solution of H,O has a pH of 2) pOH (pOH = -logl
can be used for basic solutions H + pOH = 1
Acids (HA): HA + 1-1,0 <=> A- + H,O
A - s Iii" co n i l/gal e "ds" ()/' Ih e aci d HA
Strong acid total dissociation: HC I HBr, HJ, HClO, H2S0
and IINO,
Acid equilibrium is described by K" = [A-][H,O ] [I-IA]
Weak acids have K « I pK, = -loglII(K
Common weak acids (pKy acetic (4.1 ); IIF (4 15); nitrou
(3.35): c rbonic (6.37
Lewis acid is an electron pair accepto
Bases (B): MOl 1<=> OH-+ M
B + H,o <=>
HB i s th e cOl/iI/gale a cid oI ,h" hase B
Strong base, complete dissociation: NaOH, KOH and Ba(OH)2
Base equilibrium is described by Kb =
[OH-Weak bases have Kb « I pKb = -Iog"i Kb) Common wea
bases (pK,J NH, (4.75); C - 4.70)
Lewis base is at ;electron-pair
Polyprotic acid: A compound with more tban o e i
proton (eg H,SO"H,
Amphoteric substance: A material which can react as
or a bas c
fOlming OH- or H,O :A + H20 < > HA + OH (basic, ego
F-or acetate); HX + H,o <->X + H,o' (acidic, ego NH, )
butTer: A solution ofweak acid and a salt ofits conjugate base
or a solution ofa weak base and a salt of its conjugate a id The mixture maintains "constant" pH, Henderson-Hasselbalch
equation for an acid/salt buflcr: pH = pK" t log",([salt]/[acid])
acid-base titration: React a known amount of acid with
a basic solution of unknown concentration
At the equivalence point: a moles ofacid = the moles of
base b For stTOng acid-strong base titratio , pH = 7 c
F r weak acid-strong base titration, pH >7 d For weak base-strong acid titration, pH <7 (Hydrolysis of the salt
ions changes the pH ofthe soluti n)
Reactions: Acid-rain Sulfur and nitrogen oxides react with water to give acids Strong acid/bases react with metals, produce H, and saiL Carbonates are decomposed
by acid Copper + nitric acid produces nitrogen oxides
EQUILIBRIUM
o Reactions to completion: All reactants are converted to products
o Equilibrium: The reaction reaches a steady state of for·
ward and reverse reactions
For: aA <=> bB: The equilibrium concentrations of
reagents, [At, and [B],." arc constrained by the relation
ship: K'G = [Bt,b/[At,"· K is a constant, characteristic
of the reaction at a given temperature
o Solubility Product, K,p: Defines the equilibrium
between a salt and its aqueous ions; for AX" the equilib
rium is AX/s) <=> A" (aq) + 2X-(aq), a;"d the K" = lA'-][Xl'; small K,p = low solubility
o LeChatelier's Principle: The equilibrium shifts in response to changes in temperature, pressure or reagent concentration A < > B; removing B or adding A shilis equilibrium towards the product
For increases in pressure, the equilibrium shitts to lower the total pressure (increasing the pressure raiscs the con
centration) Most relevant for gas-phase reactions
o Exothermic reaction produces heat: ";\ <=> B -t heat" ; lowering the temperature removes heat and shifts equi
librium towards the product Raising the temperature has thc opposite eflect
Endothermic reaction absorbs heat: "Heat + A <=> B";
raising the temperature adds heat and shifts equilibrium
towards the product Lowering the temperature has the opposite effect
THERMODYNAMICS
The study of the heat and work associated with a physical
or chemical process
o Types of Processes:
Reversible, the system is in a state of equilibrium
Spontaneous (irreversible), the system is moving towards a state of equilibrium
o Laws of thermodynamics:
First Law -conservation of energy, (U): The heat (q) and work
(w) associated with a process are interrelated: 60U = change in the energy of the system must correspond
interchange of heat or work with an external
Second Law - entropy, S, is conserved for a
process The disorder of the system and ings must increase for a spontaneous
Third Law -entropy is zero for an ideal crystal at T= The system is in its lowest possible energy state and ordered
o enthalpy (H): AH is the heat absorbed or produced by
a process under conditions of constant pressure (normal lab conditions)
6.H<0 for an exothermic reaction and >0 for endothermic Enthalpies of Formation, 60 HV : The 60H for the synthesis
of the compound from standard elemental !orms at 25"C
Note: These quantities can be either positive or negative
60H = (sum of product"" H l!) -(sum of reactant ~ H~ )
o entropy (S): Thermodynamic disorder:
LlS is the change in order in a system For s => I or I = g, 60S
is positive (the product in each case has more random motion)
relative to 0 K Note: Hu!se {llICll1lilit:s are 1I1m~IS {)(}\ 'iti\'l'
60S = (sum of product S") - (sum of rl'actant S") Gibbs Free Energy (G): AG All -Til:; 6oG: The capacity of the system to perform \\ork
6oG=0 for equilibrium AG<O Illt· spontancou>: If
~G>O~ the reVerse process is ~
Free energy offormation, ~(;:'
-elemental forms 1C = (sum ofpnx.lud.1.(i\!) -at 2S"C (sull1ofrei.lctant H.3'I') -The equilibrium constant K•.•1 and ,L),G arc
relatcd by the equation: 60G = -RT In(l":, /
E, )
®Reactants Reaction progress P r od~ ®
KINETICS
Rates of Chemical Process
For a generic reaction: aA h8 > cC + dO thl' rate usuaily depends on IA] and [13J
First-order rate law: Rate - ', fA] "" k,[B]
A graph of" ln[:I vs time" i:- lllL'ar, tll(.' slope
rate-constant kl half.life~ I I~ : Th : lilll": n:quin::o for the concentra
tion to decrease by a factor ofe tl, O 6~ 3 ' I: c\: Radioactive decay
Second-order rate law: Ratc - qAl' or k [BI'
A graph of ""I I VS time" line,nc slop,· is lh,' ratc
constant k,
Half-life ciwngcs during th Zero order: Rate - kll[A]" = The rate is independent "I' [AJ NOh': IAI"
Temperature-dependence of rate consta Arrhenius Law: k =A e-I: •K1 Ea is the-activati encrgy (cnergy barrier): a gl"ph of "In(k) \., I
is lincar, !>.Iop.: is -LlI R and the intc.=R"Cpt i, In( A)
Kinetics and Thermodynamics
A < > B: K fll = 1 · 1 /k ,k 1 is forward-rat,· co , t,lnt
and k., is reverse-rate Constant
CREDITS
Author: Mark
Artwo rk:
Layout: Rich M ar NOTE TO STUDENTS This QuickStudy" guide is an outline of the principles of
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