Chemistry Flashcards
charge on PROTON or ELECTRON
1.6 x 10^-19 C
rutherford
dense +ve nucleus
bohr
single e- in H atom
heisenberg
cannot know both momentum AND position of an electron simultaneously
hund’s rule
e- fill empty orbitals to stay UNPAIRED before doubling up
paili exclusion
each e- has set of 4 distinct quantum numbers
quantum numbers
n = energy level – MAX e- per energy level = 2n^2
l = angular momentum (s=0, p=1, d=2, f=3)
ml = magnetic quantum (-l to +l)
ms = spin
periodic table trends: RIGHT
- decreasing atomic radius
- increasing EN
- increasing IE
- increasing electron affinity
periodic table trends: UP
- decreasing atomic radius
- increasing EN
- increasing IE
- increasing electron affinity
highest - lowest EN atoms:
F O N Cl Br I S C H
3 exceptions to octet
- incomplete octet
- expanded octet, period 3+, d orbitals
- odd # of electrons, eg. NO has 7, can’t distribute evenly
ionic, polar covalent, nonpolar covalent
ionic = EN > 1.7 – crystal lattice, electrostatics
polar covalent = 0.5 < EN < 1.7
nonpolar covalent = EN < 0.5
formal charge
FC = (valence e-) - (nonbonding e-) - (0.5 x bonding e-)
vs oxidation assumes more EN atom gets ALL e- in bond
electronic geometry vs molecular geometry
electronic = spatial arrangement of all e-s (lone + bonds)
molecular geometry = spatial arrangement based on coordination # only (ignores lone pairs)
basic molecular goemetry for coordination #
2 = linear
3 = trigonal planar (bent)
4 = tetrahedral (trigonal pyramidal, bent)
5 = trigonal bipyramidal (sawhorse, T, linear)
6 = octahedral (square pyramidal, square planar, T, linear)
percent yield
% yield = actual/theoretical x100%
avogadros number
6.02 x 10^23 molecules/mol
normality
concentration
refrence to # of protons (3N = 3 protons)
Molarity = Normality/n
1N HCl = 1M. VS. 1N H2SO4 = 0.5M
combination reactions
A + B = C
decomposition reactions
C = A + B
combustion reactions
CxHy + O2 = CO2 + H2O
single displacement reactions
REDOX
A + BC = AC + B
double displacement reactions
eg. neutralization
AB + CD = AD + BC (or: acid + base = salt + H2O)
how many litres is 1 mol of gas at STP
22.4L
collision theory
rate of reaction is proportional to # of collisions per second (that are EFFECTIVE)
rate = total # collisions x fraction effective
use Arrhenius equation
transition state theory
transition state has HIGHEST eenrgy (peak on graph)
but it is theoretical structure, can’t isolate
rate laws
- rate = mol / Ls = M/s
- Rate = k[A]^x [B]^y
- ONLY REACTANTS in the equation
- orders ≠ coefficients – coefficients go inside the brackets, eg. 2CO2 = [2X]^y
- coefficients on RDS = orders of rate law
- value + units of k are specific for each rnx at a specific temperature
0th order reaction
- Rate = k
- independent of ANY change in [ ] of reactants
- only TEMP, CATALYST can change rate
- k = M/s
1st order reaction
- Rate = k[A]
- rate directly proportional to ONE reactant
- curved graph, log gives straight line
- eg. radioactive decay
- k = s-1
2nd order reaction
- Rate = k[A][B] OR k[A]^2
- proportional to both reactants or square of one
- more curved graph
- INVERSE gives linear graph
- k = M-1s-1
MIXED order reaction
- beginning of reaction = 1st order
- end of rxn = 2nd order
S and G at equilibrium:
- MAX entropy
- MIN free energy (G = 0)
Q < Keq, Q = Keq, Q > Keq
- Q<Keq = rxn proceeds forward, more reactants
- Q = Keq = rxn in equilibrium
- Q>Keq = reverse reaction, more products
le chatellier’s principle
- rxn will shift to offset any stress (concentration, P, V, temp)
- endothermic (heat is reactant) VS exothermic (heat is product)
- eg. temp increases, exothermic reaction shifts reverse
- must have at least ONE gaseous species to be affected by P/V changes
kinetic product
made FIRST
low temperature, fast, less energy to form
UNSTABLE
thermodynamic product
high temp, slower, more energy to transition state
STABLE (low NRG)
made over time in rxn after kinetic product
standard conditions VS. STP (ideal gases)
Standard Conditions: 25 degrees / 298K, 1M, 1atm
STP: 0 degrees/273K, 1atm
fusion
solid - liquid
MELTING
vs freezing (liquid - solid)