stuff i need to review Flashcards
a 2kg ball falls off the roof of a skyscraper that is 500m tall. ignoring air resistance, to what height will it have fallen after 6 seconds?
after 6 seconds ball will be travelling 60m/s
take average velocity- 30m/s
multiply by time- 30x6 = 180m
500-180m = 320m (will be its height)
terminal velocity is reached when?
when F(air) = F(g) when air resistance = gravity
when to use sin and when to use cos in physics equations?
when multiplying two vectors-
if the answer is a scalar, use COS(theta)
if the answer is a third vector, use SIN(theta)
only when you’re multiplying two vectors to start out with!
in physics, when do use sin vs cos in velocity equations specifically?
cos(theta) for when finding horizontal velocity (including normal force ON an inclined plane!)
sin(theta) for vertical velocity (including DOWN an inclined plane!)
you long toss a ball going 60m/s at an angle of 60* to horizontal. ignoring air resistance, what will be its horizontal velocity striking the ground?
v(x) = 60m/s x cos(60) v(x) = 60 x 0.5 v(x) = 30m/s horizontal velocity
a ball strikes the ground going 100m/s. from what height did it fall?
if going 100m/s, it must have fallen 10s ago
100m/s is final velocity, take average- 50m/s
50m/s x 10s = 500m initial height
you throw a rock horizontally going 40m/s from a 125m cliff. how far from the bottom of the cliff does the rock hit the ground?
find time in air first x = 1/2at^2 125 = 1/2(10)t^2 t = 5s horizontal velocity is constant 5s x 40m/s = 200m
a 4,000kg fresh-water fish floats on water and is 1/4 submerged. What is the volume of the fish?
1/4 submerged means that mass of water that would fill 1/4 volume of fish would be 4,000kg
density of water is 1,000kg/m^3
D=m/v
1,000 = 4,000/v –> v = 4m^3
this volume is only 1/4 of fish, so total volume of fish is 16m^3
what is the specific gravity of a liquid in which a boat with a specific gravity of 2.5 is 1/4 submerged?
if ball is 1/4 submerged, then liquid must be 4x dense as the boat. 2.5 x 4 = specific gravity of 10
specific gravity = density / density(water)
25kg ball is placed in unknown liquid and has apparent weight loss of 25N. If the density of the ball is 11g/cm^3, what is specific gravity of unknown liquid?
apparent weight = actual weight - Fb
(so Fb = apparent weight loss)
Fb = pvg (density and volume of fluid, x gravity)
Fb = weight of fluid displaced = apparent weight loss
actual weight of ball = (25)(10) = 250N
ball’s worth of fluid weighs 25N (Fb), while ball weighs 250N
the fluid is 10x less dense than ball
so 11g/cm^3 / 10 = 1.1g/cm^3 is density of fluid
a ball with density of 8x10^2kg/m^3 floats in a liquid with density of 1x10^3kg/m^3. What fraction is above the surface?
liquid density = 1x10^3, ball density = 8x10^2, or 0.8x10^3
this means ball is 0.8 density of liquid
so 0.8 of ball will be below, therefore 0.2 of ball will be above liquid- this is 2/10 or 1/5 of ball
difference between representative heuristic and availability heuristic
representative heuristic: stereotype
availability heuristic: most recent example that comes to mind
stereotype threat vs self fulfilling prophecy
stereotype threat: institutional
self-fulfilling prophecy: individual encounter of someone else imposing stereotype on you
adiobatic
no heat transfer
which of these is soluble:
BaNO3
BaSO4
AgBr
BaNO3- nitrates are always soluble
sulfates not soluble
silver + Cl-, I-, Br- not soluble
what is the centripetal force of your 3kg arm, moving 5m/s, if your arm is 1m long?
F = mv^2/r F = (3)(5^2)/1 = 75N
Ka x Kb?
alternatively, pKa + pKb?
Ka x Kb = 10^-14
pKa + pKb = 14
when is filtration used? when would you use gravity vs vacuum filtration
separate solid from a liquid
gravity: product of interest is in filtrate
vacuum: solid is desired product
are amino groups electron donating or withdrawing
donating
reactivity of metals with water is due to what property of metals?
low ionization energy
in general, all acids react with metal carbonates to form…
CO2 and related salt (decarboxylation)
what can be done to increase percent yield
removal of product
temperature and catalyst affect rate only
temp can also increase Keq (but this is distinct from percent yield)
what is at play during color changes in flame tests and solution chemistry, respectively
flame test = photon emission
solution chemistry = partially filled d orbitals
beta decay
neutron –> proton (antineutrino emitted)
loss of electron
larger negative heat of combustion mean what?
less stable species
more stable species have smaller negative heat of combustion, aka more positive heat of combustion
“-ic” vs “-ous” means what for acids?
“-ic” means more oxygen than “-ous”
ex: HNO3 = nitric acid (nitrate), but HNO2 = nitrous acid (nitrite)
(“-ic” = “-ate”, while “-ous” = “-ite”)
where is the half-equivalence point on a titration graph?
[HA] = [A-] at half-equivalence point, which is at horizontal portion
reminder, strong/strong titrations do not have half-equivalence points
glycogen synthase catalyzes formation of what bond
alpha-1,4-glycosidic bond in glycogen (the branched bond)
alpha-1,6-glyosidic bond is more common in glycogen but not the one made by glycogen synthase
nucleotides are linked by phosphodiester bonds between….
5’ sugar (hydroxyl group) and 3’ phosphate group
proinsulin is cleaved into insulin before secretion in the ____ of the cell
ER- for secreted proteins
ribosomes- for cellular proteins
explain surface tension
contractive tendency of surface of liquid that allows it to resist external force (cohesive forces)
Ts = F/d (force/length)
due to the fact that liquid molecules on top are touching air, so they bond stronger to molecules below
higher surface tension = harder to break through surface of liquid (to evaporate)
ex: surfactant lowers surface tension in lungs so they can expand more easily
also: increased temperature (higher KE) lowers surface tension (ability to resist escape) –> boiling
what property of sound waves depends on the medium
speed of sound depends on bulk modulus, density, and temp of medium (v = [sqrt] bulk modulus/ density)
general formula for speed of a wave
v = [sqrt] bulk modulus/ density
MHC I vs MHC II
MHC I expressed on ALL cells (self proteins). will trigger cell mediated immunity if deemed foreign
MHC II expressed on APC ONLY. will trigger humoral immunity if deemed foreign
how to know if something is H bond donor or acceptor or both?
if something has an H bond in it, it can donate and accept
electronegative atoms that do not already have an H attached are H bond acceptors only (O in carbonyl, O in ether, etc)
glycosidic bond
oxygen of hydroxyl (nucleophile) attacks anomeric carbon of sugar hemiacetal, forming acetal. bond between is a glycosidic bond
SDS is used in: electrophoresis, isoelectric focusing, both, neither?
just electrophoresis- SDS disrupts the charges so proteins are only separated by size
northern vs southern vs western blotting
northern- RNA, western- protein, southern- DNA
what has alpha-tubulin: microvilli, flagella, cilia
cilia and flagella. alpha-tubulin is microtubule component
deductive vs inductive reasoning
inductive = top down: goal or general idea (hypothesis) guides thinking
deductive = bottom up: data or observations guide thinking
which amino acid has amino group on the right in Fischer projection
cysteine (R)
L amino acids have amino group on the LEFT
(L = Left)
compare starting materials for Strecker and Gabriel synthesis, both of which produce both L and D amino acids (racemic) because they start with a planar molecule
Strecker: aldehyde + NH4Cl + KCN
Gabriel: potassium phthalimide, diethyl bromomalonate, alky halide
(products are NOT optically active)
what bond links nucleotides
phosphodiester (phospho di ester) between sugars of nucleotides
pyrophosphate
PPi
this type of spectroscopy measures molecular vibrations, such as bond stretching or bending. what is it and what type of molecule does it require
IR (infrared) spectroscopy- requires net dipole moment for molecule to be detected
absorption of light changes bond vibration, and changes dipole moment
this type of spectroscopy dissolves sample in inert, non-absorbing solvent, and absorbance is plotted against wavelength. the max absorbance shows extent of conjugation. what type is this and what causes absorbance?
UV (ultraviolet) spectroscopy- measures conjugation. absorbance caused by electronic transition between orbitals
more conjugation = longer wavelength of max absorbance (lower energy)
this type of spectroscopy relies on absorption of radiation that causes excitation at different frequencies, depending on the atom’s magnetic environment. the graph is frequency vs absorption of energy. what is this, and what does it require?
nuclear magnetic resonance (NMR)- requires atom with nuclear spin (odd atomic number, odd mass number, or both)
what do each of these mean for NMR?
integration
spin-spin coupling (splitting)
n+1 rule
integration: area under peaks, these correspond to ratio of protons produced at each peak
splitting: protons in close proximity to one another that are not identical, but influence each other (causes multiplets)
n+1 rule: proton with ‘n’ neighboring protons (3 bonds away) will show with n+1 peaks
what are NMR values for aldehyde, carboxylic acid, and aromatic ring
deshielded = downfield = left
aromatic ring: 6-8.5ppm
aldehyde: 9-10ppm
COOH: 10.5-12ppm
IR spec tells you ____, UV spec tells you ____, NMR tells you ____
(hint: how can they be used together to identify molecule)
IR = functional groups UV = conjugation NMR = arrangement of functional groups
what layer will be on bottom in extraction (and what kind of solution is it usually)
denser layer on bottom- this is usually the aqueous layer (with organic on top)
in extraction, why does adding base help extract acid into aqueous phase?
acid dissociates, anion formed will be more soluble because it is charged
superheating
liquid is heated to temp above its boiling point without vaporization- gas bubbles within liquid are unable to overcome atmospheric pressure and surface tension
explain how fractional distillation works
fractional column increases surface area (using glass beads or steel wool)
vapor rises up column, condenses on surface, refluxes back down until rising heat causes it to evaporate again- condenses higher up in column
every time the condensate evaporates, it’s a higher proportion of compound with lower boiling point (purifies it)
how to calculate Rf in TLC
Rf = distance spot moved/ distance solvent front moved
nonpolar travel farther (unless it’s reverse-phase)
proximal vs distal stimulus
distal stimulus- stuff in the world
proximal stimulus- stuff that actually reaches your senses
how many sigma and pi bonds in a double bond? in a triple bond?
double bond = 1 sigma + 1 pi
triple bond = 1 sigma + 2 pi
what determines energy of a photon
separation between energy levels = energy of photon (large separation = higher energy photon)
ping pong reaction mechanism
double displacement- no ternary complex forms
binding of 2 substrates causes enzyme to switch back and forth between 2 states
carnitine shuttle
transports FA into mitochondria for beta oxidation
how do pCO2 and pH relate to hemoglobin oxygen curve
increase pCO2 or decrease pH —> lower affinity of hemoglobin for oxygen
sizes of prokaryotic and eukaryotic ribosomes
eukaryotic = 60S + 40S = 80S prokaryotic = 50S + 30S = 70S
sites of amino acid translation, in correct order
A- amino acid
P- peptide
E- exit
amber codon
stop codon (UAG, UAA, UGA)
Carl Roger’s incongruence
gap between person’s actual self and ideal self (Rogers is humanist)
functions of cornea, iris, retina, lens
cornea/iris accommodate incoming light rays, lens focuses incoming light on photoreceptors, which are in retina
Big Five personality trades (Cattell)
neuroticism, agreeableness, extraversion, conscientiousness, openness
overextension (psych)
using a term too broadly
what property of a wave is determined by medium. which property never changes between mediums?
velocity is DETERMINED by medium
frequency is INDEPENDENT of medium
(and if velocity is changed by medium and frequency never changes, that is why wavelength must change!)
distance between adjacent nodes in a wave
1/2 wavelength
what causes effect of a prism
refraction- wavelengths of differing colors travel at different speeds, so bend at different angles when they hit a medium with a different index of REFRACTION –> dispersion (separation of colors)
different from diffraction because this is just light waves bending around something it its way (no separation of colors, index of refraction is the same)
phosphorylase vs phosphatase
phosphorylase = kinase phosphatase = REMOVE phosphate
analogous vs homologous structures (in evolution)
analogous- developed separately but serve same function (wing of bee, wing of bird)
homologous- share evolutionary history but have different functions (arm of human, fin of walrus)
structure of chlorate and nitrate? Chlorite and nitrite?
chlorate (ClO3-): 2 double bond O, 1 negative charge O, 1 lone pair
nitrate (NO3-): 1 double bond O, 2 negative charge O, positive charge on N, no lone pairs
chlorite (ClO2-): 1 double bond O, 1 negative charge O, 2 lone pairs
nitrite (NO2-): 1 double bond O, 1 negative charge O, 1 lone pair
enantiomer vs epimer
enantiomer- R/S switched at EVERY chiral C
epimer- R/S switched at ONE chiral C
meso compounds have plane of symmetry and opposite R/s at every spot across plane of symmetry, so substituents have to be on ___ side of plane
SAME side of plane
when ____ react with chiral molecule, 2 different substituents are formed
ENANTIOMERS
(tetra/mono) substituted alkene is most stable, and has (high/low) heat of combustion
TETRA substituted alkene is MOST STABLE- has LOW heat of combustion because it is STABLE (does not want to combust, will not give you a lot of heat)
but tetra-substituted alkenes are more reactive as nucleophiles than less substituted alkenes
(trans/cis) is better for stacking
TRANS- keeps C main chain more straight
which is electrophile, which is nucleophile?
carbonyl, alkene
carbonyl C is e- WITHDRAWING (because it has partial positive due to electronegative atom attached)–> carbonyl is ELECTROPHILE
alkene is NUCLEOPHILE (double bond is e- dense, but lacks electronegative substituent)
which is nucleophile, which is electrophile?
alcohol, HCl
alcohol = classicccc nucleophile HCl = GREAT electrophile (partial + on H because of dipole moment with Cl)
tell me about combustion of methane
easily propagated BUT has high energy of activation. however, this is overcome by being a highly exothermic reaction (heat provides energy). also, proceeds via radical reaction
low Kd means
higher affinity
kcat equation
kcat = vmax / [E] where [E] is enzyme concentration (in a saturated solution)
catalytic efficiency = kcat/ Km
Lewis acid-base interaction between metal cation and electron pair donor
coordinate covalent bond
what is SDS
detergent (NOT reducing agent! need reducing conditions to break up disulfide bonds)
dissociative disorder
disconnection in thought, selective forgetting, trying to escape reality in involuntary/unhealthy ways
which sociological theory points to manifest and latent functions?
functionalism- manifest = intentional function, latent = unintended side effect function
what happens to velocity of wave when music goes from air to through a wall?
velocity of sound INCREASES in solids and liquids compared to gases (light waves travel SLOWER than when in air)
if a mutation in the Lac operon impairs the ability of the REPRESSOR to bind the OPERATOR region, the Lac operon genes will be transcribed under what conditions?
constitutively active, in presence of both glucose and lactose. Lac operon encodes for genes involved in lactose metabolism- repressed until glucose is not available
saponification
basic hydrolysis of ester
ester –> alcohol + acid salt
how does increasing temperature affect voltage in a wire?
higher temp = higher resistivity
R = (resistivity)L / A
V = IR
higher temp = lower voltage
how does voltage change for batteries in parallel vs batteries in series? what about current?
batteries in parallel- voltage is the same (separate loops), current changes (additive)
batteries in series- voltage is additive (one single loop), current is the same
rank in order of increasing polarity
water, sugar, ethanol
sugar < ethanol < water …. aka decreasing amount of carbon
for the MCAT- sugar is highly nonpolar!!
what is the charge at the cathode
cathode is NEGATIVE charge which is why it attracts CATIONS and this is where reduction occurs (of the cations!)
how to find pOH given concentration of base and its conjugate acid
pOH = pKb + log[conjugate acid]/[base]
for both pOH and pH…. conjugate species goes on top, aka reactants over products
pKa on a titration curve?
pKa = HALF equivalence point, aka buffer region, aka flat region, aka [acid/base]=[conjugate base/acid]
(equivalence point is steep region, where [H]=[OH])
why is no work done in circular motion
W=Fdcos(theta)
angle between force (inward) and velocity (tangential) is 90, and cos90=0
work uses (sin/cos), while torque and magnetics uses (sin/cos)
work = COS (vector and scalar being multiplied!)
torque (T=Flsin) and magnetics (Fb=qvBsin) use SIN (two vectors, getting a third direction!)
how to use right hand rule
RIGHT HAND
thumb = force vector
pointer finger = velocity vector
other fingers = magnetic field vector
all angles perpendicular to each other
blood pH during exercise?
CO2 + H2O -> H2CO3 -> HCO3- + H+
exercise produces CO2 -> push equation to right -> DECREASE pH
increase respiratory rate -> blow off CO2 –> push equation left -> increase pH
which would be best for measuring transcription? RT-PCR Western blot Southern blot qPCR
RT-PCR –> measures mRNA. uses RT to make DNA out of RNA, then amplifies it
(southern- measures DNA, western- measures protein, qPCR- levels of DNA)
how many sigma and pi bonds in single, double, and triple bond?
single bond- one sigma bond (sp3, 25% s)
double bond- one sigma, one pi bond (sp2, 33% s)
triple bond- one sigma, two pi bonds (sp, 50% s)
definition of current
flow of charge per unit time
electric fields inside each of the conductors that forms a capacitor is zero. how is this possible?
free electrons on the surface of the conductors arrange themselves to create an internal electric field that perfectly cancels out the external electric field. therefore net electric field in the conductor is 0
does SN2 or SN1 favor polar protic solvents and why
SN1 favors polar protic solvents because SN1 is a 2 step rxn that proceeds through carbocation intermediate (carbocation formation is rate limiting). polar protic solvent stabilizes the carbocation
what kind of image is formed by glasses with a -50cm lens focal length?
negative focal length = diverging lens = virtual, reduced image when object is farther than focal length
view point of conflict theorist =
stratification always
script vs schema (psych)
schema = ideas script = how to act in a given situation
