General Chemistry Flashcards
what is the equation for angular momentum of an electron? for energy of that electron?
L = nh/2pi
E = -Rh/n^2
pauli exclusion principle
no two e- in an atom can possess the same set of four quantum numbers
how to determine the maximum # of e- in a shell?
what is max # of e- in subshell?
2n^2, where n = principle quantum #
4L+2
explain the 4 quantum numbers
- n = principle quantum # (energy level) (also tells you # subshells)
- L = azimuthal (angular momentum) quantum # - refers to shape/#shells within given principle energy level
- mL = magnetic quantum # (specifies particular orbital within sub shell where e- is most likely to be found) (2L+1 possible values for mL)
- mS = spin quantum # (e- spin orientation) (+1/2 or -1/2)
how does n limit L? how does L limit mL?
L = 0 to n-1
mL = -L < mL < +L
explain spectroscopic notation
shorthand representation of principal azimuthal quantum #’s
L=0, called s; L=1, called p; L=2, called d; L=3, called f
ex) e- in shell n=4 is in 4d
explain electron configuration
first number denotes principal energy level (n), letter designates sub shell (L) , and superscript gives # e- in that shell
ex) 2p^4 means 4 e- in second (p) sub shell of second principal energy level
what is the aufbau principle?
electrons fill from lower to higher energy subs jells, and each sub shell will completely fill before electrons enter next one
what is hund’s rule?
within a given subshell, orbitals are filled such that there are a max number of half-filled orbitals w/ parallel spins
paramagnetic vs diamagnetic
paramagnetic is the presence of unpaired e- (and PARALLEL spins & ATTRACTION), while diamagnetic is paired e- (and REPELLED)
what are valence electrons? are they easy or hard to remove? explain groups
the e- in outermost energy shell, easiest to remove
- Groups 1 & 2, only highest s subshell e- are valence
- Groups 3-12, highest s&d subshell e- are valence
- Groups 13-18, highest s&p subshell e- are valence
A elements
representative elements
IA-VIIIA
S or P subshells
B elements
nonrepresentative elements
transition/actinite/lanthinide series
S and D subshells
explain properties of each of the following: metals, nonmetals, metalloids
- metals - luster, malleable, low EN, high atomic radius, low e- affinity, EASILY GIVE UP ELECTRONS
- nonmetals - brittle, high IE, high EN, small atomic radius, DO NOT EASILY GIVE UP ELECTRONS
- metalloids - medium EN and IE, luster but brittle and poor conductor
what is Zeff? trend?
effective nuclear charge, it is the electrostatic attraction b/w valence shell e- and the nucleus
- it is a measure of the net positive charge experienced by the outermost e-
- increases going from left to right
what is the principal quantum # trend seen in the periodic table? what does it mean?
moving down a column, principal quantum # increases by one each time
- the valence e- are increasingly separated from nucleus by greater # filled principal energy levels, which reduces attraction b/w valence e- and nucleus, valence e- held less tightly
what is ionic radius trend?
increases as you go left to right because adding electrons increases size of atom
ionization energy; how does Zeff affect IE?
What is first vs second IE?
energy required to remove e- from gaseous species (endothermic)
- larger Zeff or closer to valence e- means more tightly bound and thus a higher IE
- 1st IE is energy to remove 1st e- and 2nd is for 2nd e-
electron affinity, what is the trend?
energy dissipated by gaseous species when it gains an e- (Exothermic)
- essentially opposite of IE
- increases going left to right, decreases top to bottom
define trends for AR, IE, EA, EN
- AR decreases L to R/increases T to B
- IE increases L to R/decreases T to B
- EA increases L to R/decreases T to B
- EN increases L to R/decreases T to B
octet rule exceptions
- Incomplete octet - these elements are stable w/ <8 e- (H, He, Li, Be, B)
- Expanded octet - any element in period 3 and greater, holds more than 8 e- (P,S,Cl, period 3 and greater)
- Odd # of e- - any molecule w/ an odd # of valence e- can’t distr. to give 8 e- to each (ex. NO has 11)
ionic bonding
one or more e- from an atom w/ low IE (usually metal) are transferred to an atom w/ high EA (usually nonmetal)
- ex. NaCl
covalent bonding; polar vs nonpolar
What is a coordinated event?
e- pair is shared b/w 2 atoms (usually nonmetal), w/ similar EN values
- if e- pair is shared equally it is nonpolar covalent, and unequally is polar covalent
A coordinated event is when both of the shared e- are contributed by only one of the 2 atoms
what are some characteristics of ionic compounds?
high MP, high BP, crystalline lattice in solid state (repeating + and - ions), dissolve readily in H2O, good electrical conductors in molten/aqueous states
explain bond strength and length of single, double, and triple bonds
what is bond order (for triple bond as an example)?
single - longest and weakest
double - medium and medium
triple - shortest and strongest
bond order is the # shared e- b/w 2 atoms (ex. triple bond has bond order of 3)
bond energy
energy required to break a bond by separating its components into their isolated gaseous atomic states
what are the diatomic elements that form non polar covalent bonds
H2, N2, O2, F2, Cl2, Br2, I2
what is the equation for a dipole moment and define variables
p = qd
p is dipole moment, q is magnitude of charge, d is displacement vector separating 2 partial charges
what is the formal charge equation?
FC = (V e-) - (NB e-) - 1/2(B e-)
how to draw a lewis dos structure?
- draw out backbone of compound, least EN atom is central (H and usually halogens are terminal)
- count all Ve- and make sure sum is achieved
- draw single bonds
- complete octets
VSEPR theory
uses lewis dot structures to predict molecular geometry
- draw lewis dot structure
- count total Be- and NBe- of CENTRAL ATOM
- arrange e- pairs around central atom so they are as far apart as possible
electronic vs molecular geometry
coordination number
electronic describes spatial arrangement of all pairs of e- around central atom (including NB and B e-), while molecular describes spatial arrangement of only B e-
- # of atoms that surround and are bonded to central atom (helps determine geometry)
bonding vs antibonding orbitals
sigma vs pi bonds
bonding is when signs of 2 atomic orbitals are the same, antibonding is when the signs are different
sigma is when orbitals overlap head to head, allowing for free rotation about their axes, while pi is when there are 2 parallel overlap e- cloud densities, and there is not free rotation
rank intermolecular forces from weakest to strongest
london dispersion < dipole dipole < H bond < covalent
what is a london dispersion (van der waals) force?
attractive/repulsive interactions of short-lived and rapidly shifting dipoles
what is a dipole-dipole interaction?
a temporary positive attractive force from + end of dipole to - end
what is the equation for gram equivalent weight? and explain equivalents in terms of hydrogen ions, for example
gram equivalent weight = molar mass/n
for H2SO4 (62g/mol), we’d need 31g in order to obtain 1 eq. of H+ ions.
what is normality? what is the equation for converting from normality to molarity?
normality is a measure of concentration in equivalents/L
Molarity = normality/n (n is # protons)
empirical vs molecular formulas
empirical gives the simplest whole number ratio of the elements in the compound, while molecular gives the exact # of atoms in the compound
what is the equation for % composition of an element?
% composition = mass of element in formula/molar mass x 100%
how to determine empirical and molecular formula?
- assume there are 100g -> each % x100g
- Divide each amount by molar mass
- Divide each resulting # by lowest number (3.3/3.3, 4.5/3.3)
- find lowest whole number ratio to fit
MOLECULAR: - divide total molar mass by empirical molar mass
- multiply empirical formula by that integer
what is a combination reaction? example?
what is a decomposition reaction? example?
2 or more reactants forming 1 product
2H2 + O2 -> 2 H2O
1 reactant forming 2 or more products
2HgO -> 2Hg + O2
single vs double displacement reactions w/ examples
SINGLE - occurs when atom/ion in compound is replaced by atom/ion of another element
Cu + AgNO3 -> Ag + CuNO3
DOUBLE - elements from 2 diff compounds swap places
CaCl2 + 2AgNO3 -> Ca(NO3)2 + 2AgCl
combustion reaction & example?
neutralization reaction & example?
- involves a fuel (usually hydrocarbon), an oxidant (usually O2). and they form CO2 and water
CH4 + 2O2 -> CO2 + 2H2O - type of double-displacement where acid reacts w/ base to produce a salt (and usually H2O)
HCl + NaOH -> NaCl + H2O
talk about compounds ending in -ide, -ite, and -ate and starting with hypo- and per-
- monoatomic anions end in -ide (H- = hydride, F- = fluoride)
- when a compound forms 2 oxyanions, the one w/ less oxygens ends in -ite and more ends in -ate (NO2- = nitrite and NO3- = nitrate)
- for extended series, hypo means less and per means more (hypochlorite, chlorite, chlorate, perchlorate)
explain the collision theory
how do you incase reaction rate in arrhenius equation?
rate of rxn is prop. to # of collisions per sec. b/w reacting molecules
decrease Ea or increase temp.
define the following
- zero-order rxn.
- first-order rxn.
- second-order rxn.
- mixed-order rxn.
dynamic vs. static equilibrium
- zero-order rxn. - rate of formation of product is independent of changes in conc. of reactants (only temp. or catalyst can change rate)
- first-order rxn. - rate prop. to only one reactant
- second-order rxn. - rate prop. to conc. of either rxn
- mixed-order rxn. - non-integer orders or varying orders
dynamic is when forward/reverse rxns are still occurring, static is when they’ve stopped
relationship b/w Q and Keq
the larger Keq is _________
- If Q < Keq then forward rxn has not reached eq. and more reactants than at eq; deltaG < 0
- If Q = Keq then reaction is dynamic eq. and deltaG=0
- If Q > Keq then forehead rxn. exceeded eq. and deltaG >0
the further to the right the rxn is
given reaction: A (aq) + 2B (g) => C (g) + heat will shift right if: - - - - will shift left if: - - - -
Right: - A or B added - C removed - P increases or V decreases - T decreases Left: - C added - A or B removed - P decreases or V increases - T increases
isolated vs. closed vs. open systems
explain deltaU, G, Q for
- isothermal
- adiabatic
- isovolumetric
isolated is neither energy nor matter can be exchanged w/ surr; closed is just energy but not matter can be exchanged; open is both can be exchanged
- isothermal - deltaU=0, so Q=W
- adiabatic - Q=0, so deltaU= -W
- isovolumetric - deltaU=Q, no work done
state functions mnemonic
standard conditions vs. STP
what is the relationship b/w alkane size and combustion?
when im under PRESSURE and feeling DENSE, all I want is TV and HUGS
standard conditions is 25C (298K), 1atm pressure, 1M; STP is 0C (273K), 1atm
larger alkane = larger combustion
LOOK UP AND KNOW EVERY SPACE AND LINE OF A PHASE DIAGRAM
OKAY
define endo and exothermic (Q and H)
when is bond enthalpy positive? negative?
what is the change in entropy equation?
endothermic is deltaQ>0 and deltaH>0, so the system absorbs heat; exothermic is deltaQ<0 and deltaH<0, so the system releases heat
positive when breaking bonds, negative when forming bonds
S=Qrev/T
converting b/w atm and mmHg? what volume does 1mol gas occupy at STP?
what is boyle’s law (V vs. P) and charles’ law (V vs. T) and Gay-Lussac’s law (P vs. T) and Henry’s law ([A] vs. P)?
1atm = 760mmHg
22.4L
P1V1=P2V2; V1/T1=V2/T2; P1/T1=P2/T2; [A1]/P1=[A2]/P2
when new interactions are stronger than initial ones, solvation is _____ and then new ones are weaker it is_________
what are the first 2 solubility rules?
exothermic; endothermic
- all salts containing NH4+ and alkali metal (group1) CATIONS are water-soluble
- all salts containing NO3- and CH3COO- ANIONS are water-soluble
molarity vs. molarity (units)
what is normality?
what is the dilution equation?
molarity is mol/L and molality is mol/kg
normality (N) is # eq. of interest per L of soln
MiVi=MfVf
what is the common ion effect?
how does adding solvent affect vapor pressure? (Raoult’s law)
what is boiling point elevation formula? freezing point depression formula?
solubility of a salt is reduced when dissolved in soln already containing one of the constituent ions
adding solute decreases vapor pressure of solvent
deltaTb = iKbm deltaTf = iKfm
bronsted-lowry acid vs base?
lewis acid/base?
amphoteric? amphiprotic?
BL acid donates H+, BL base accepts H+
Lewis acid is e- acceptor, lewis base is e- donor
amphoteric can be acid or base; amphoprotic can gain or lose H+
how to solve for -log(n x 10^-m) ?
equation for finding unknown concentration of titrand? (N and V)
m - 0.n
NaVa = NbVb
oxidation # rules
- free elements have Oxid. # of 0
- Oxid. # of monoatomic ion is equal to the charge (Na+ = +1, Cl- = -1)
- Group I oxidation # is +1
- Group II oxidation # is +2
- Group VII is -1 EXCEPT when combined w/ higher EN atom
- Hydrogen is usually +1, sometimes -1 w/ less EN atoms
- Oxygen is usually -2
- sum of oxidation # in neutral compound is 0
how to balance half rxn in acidic soln? basic soln?
what is a spectator ion?
combination vs decomposition reactions
Acidic - use H2O to balance O and H+ to balance H
Basic - use OH- to balance O and H2O to balance H
ion that is unchanged in charge across the reaction
combination is when 2+ species come together to form a product, decomposition is when 1 product breaks into 2+ species
what is a combustion rxn?
what is a double displacement rxn?
what is a disproportionation rxn?
a fuel (usually hydrocarbon) is mixed w/ oxidant (usually Oxygen) forming CO2 and H2O
when counter ions switch places
element undergoes both oxid. and red. in producing its products
electrodes in electrochemical cell mnemonic
what is electromotive force (emf)? +emf vs -emf
which direction does current flow in electrochemical cell? which direction do e- flow?
AN OX and a RED CAT
- anode does oxidation and cathode is reduction
emf is voltage or electrical potential diff. of the cell
- + emf cell is able to release energy (deltaG<0) and -emf cell must absorb energy (deltaG>0)
cathode to anode
A->C
how to construct a cell diagram? (ex)
galvanic vs. electrolytic cell
electrodeposition eq. and mnemonic
Zn | Zn2+ (1M) || Cu2+ (1M) | Cu
anode | anode soln (conc.) || cathode soln. (conc.) | cathode
galvanic is spontaneous, electrolytic is non spontaneous and requires electrolysis (chem. comp. decomp.)
mol M = I(t)/nF
calculating mol. M, It is Not Fun
what is unique about a concentration cell?
what is a rechargeable cell?
what is energy density (high vs. low)?
it is a type of galvanic cell (spontaneous), but the electrodes are chemically identical, therefore current is generated as a function of concentration gradient established b/w the two solutions
cell that can act as galvanic or electrolytic
measure of battery’s ability to produce power as a function of weight (low energy density requires heavier amount of battery material)
in cells, when is anode positive/negative and cathode positive/negative?
what is reduction potential (talk about high vs. low)
- talk about electrodes in each cell w/ their reduction potential
- galvanic cell, anode negative and cathode positive
- electrolytic cell, anode positive and cathode negative
tendency for species to gain e- (be reduced); more positive means more likely to be reduced
- galvanic cells have more positive RP in cathode, electrolytic cells is anode
how are deltaG and emf related?
what is nernst eq. for cells?
deltaG = -nF(Ecell)
n is mol of e- transferred, E cell is standard emf
Ecell = E(0)cell - RT/nF(lnQ)
