Chem/phys flashcards mcat

ionic radii patterns

• decrease with increasing atomic #

• in isoelectronics species (same # of e-), ionic radii decrease with increasing atomic #

• helpful in comparing cations, anions, & neutral atoms

catalyst changed activation energy; how do different activation energies affect reaction rate

• only rate at which equilibrium is achieved changes, but equilibrium constants are still the same

law of mass action

expression w/ respect to equilibrium constant of rxn

• when applied to dynamic equilibrium of elementary rxn, this law states rate of rxn is proportional to molar amount of each reactant raised to its power

• rxn order = stoichiometric coefficient

How do catalyst particles affect surface area?

• increase surface area

• increase rxn rate by stabilizing transition state

where are e- generated & where do they flow to?

• generated at anode (oxidation) & flow twds cathode (reduction)

electromagnetic spectrum wavelengths for each color

• red: 650 to 740

• orange: 590 to 650

• yellow: 565 to 590

• green: 490 to 565

• blue: 450 to 490

• violet: 400 to 450

Strong bases

• Group 1 OH

• Group 1 oxide

• some group 2 hydroxide: Ba(OH)2, Sr(OH)2, Ca(OH)2, Metal oxides (NaNH2)

Strong Acids

• HI

• HBr

• HCl

• HClO4

• H2SO4

• HNO3

Electrical conductivity patterns

metal > metalloids > nonmetals

Conduction

heat transferred thru direct contact

Radiation

heat transferred thru emission & absorption of electromagnetic waves

Convection

heat transferred w/ flow of matter

Increasing stability for carbanion

• methyl > primary > secondary > tertiary

how are multimeric proteins bound tg

• noncovalent interaction, but can also have cov disulfide bonds btwn cysteine residues (broken by reducing agents)

Simple distillation:

• used for mixtures of liquids that have bp below 150 C & more than 25C diff

Fisher projection

• vertical lines: go to back of page, like dashes

• horizontal lines: come out of page, like wedges

IR spectroscopy, measure molecular vibrations

• Alkane: 2850-2960

• Alkene-H: 3020-3100

• Alkene: 1640-1680

• Alkyne-H: 3300

• Alkyne: 2100-2260

• Alkyl halide

  • C-Cl: 600-800

  • C-Br: 500-600

• Alcohol

  • OH: 3400-3650

  • C-O: 1050-1150

• Arene

  • C-H: 3030

• Aromatic:

  • 1660-2000

  • 1450-1600

• Amine:

  • N-H: 3300-3500

  • C-N: 1030-1230

4 characteristics of ideal gases

1. no attractive/repulsive forces

2. size/ molecular volume of the individual gas molecules of an ideal gas is negligible (as zero), compared to volume/space of container the gas occupies

3. collisions btwn molecules of ideal gas are completely elastic (no E lost by interac or friction)

4. ideal gas molecules have average KE/ energy of motion that is directly proportional to gas temp

• ideal under high T & low P

elastic collision vs inelastic

Elastic= same KE

• w/o attractive interactions

• no KE loss

• total E of motion is unchanged

Inelastic = same KE

• interactions occur during collision

• some KE lost in collision

• lost E changed to other forms (i.e heat)

lewis acid

accept e-

lewis base

donate e-

Bronsted-lowry acid

donate H+

Arrhenius base

produce OH-

Pourbaix diagram

• boundary lines btwn species domains indicate transition from 1 species to another

• along boundary btwn aq & precipitating solid species, equilibrium can exist

• show relationship btwn chemical species as function of given conditions

• boundary lines btwn domains indicate transition from one species to another, also indicate equilibrium btwn aq & precipitating species

• boundaries parallel to axis show constant ranges independent of changes

Bronsted lowry base

accept H+

galvanic cell

convert chemical E to electrical E via spontaneous redox rxns, acts as a power source

• chemical to electrical

• Delta G < 0

• Anode (-)

• Cathode (+)

• no energy source required

electrolytic cell

uses external electrical energy to force non-spontaneous redox rxns, act as an energy consumer

• electrical to chemical

• Delta G > 0

• anode (+)

• cathode (-)

• energy source required

Gas chromatography & phases

• Vaporizes the liquid before separation, molecules are separated based on boiling point

• consists of injection port, mobile & stationary phase, column in heated oven, detector, & computer for data analysis

• molecules w/ lower bp reach detector before molecules w/ higher bp

1. mobile phase: inert gas, i.e: helium or nitrogen

2. stationary phase liquid that coats solid support on inside of column

how are gamma rays & intensity related?

more gamma rays = higher intensity

how are intensity of electromagnetic radiation related to individual energy of each emitted particles & # of particles emitted per unit time?

proportional, increase w/ higher photon E & emission rate

electrochemical cell

e- are always transferred from anode (where oxidation occurs) to cathode (where reduction occurs)

galvanic cell

overall cell potential must be positive & the electrode w/ greater standard reduction potential has a greater tendency to be reduced & function as cathode

relationship of wavelength to frequency & energy

inversely proportional

destructive interference

when path length of 2 waves differ by half the wavelength

• diff in path length that are integer multiples of wavelength cause constructive interference

what is necessary for decarboxylation?

B-carbonyl is necessary bc cyclic transition state incorporating both carbonyls is formed

A photon is absorbed when…

it goes from lower, more stable E level to higher, unstable E level

A photon is emitted when…

it goes from higher, unstable E level to lower, stable E level

trend of atomic size

cations are smaller (greater tug, less e-) & anions are larger (smaller tug, more e-)

transverse waves displace components of medium ___________ to direction of wave’s propagation

perpendicular

longitudinal displace medium in a direction _____________ to direction of wave’s propagation

parallel

mechanical wave

created by disturbance in medium