Dawn - CP - Flashcards
What is the phase shift in order to get complete destructive inteference?
destructive interference = 180 shift
When temperature increases, what direction does that shift equilibrium based on endo and exothermic reaction?
if DeltaH > 0 = endo = shift to product side
if DeltaH < 0 = exo = shift to reactant side
What does the reaction between sulfur dioxide and water produce?
Sulfurous acid (H2SO3)
Why would you have a reaction quotient that doesnt equal a Keq?
- If Keq = Q then youre in equilibrium, but if Q is smaller then you have more products
What does the Kp express? and how do we determine the mole fraction?
Kp = product partial pressure/ reactant partial pressure
- Take that value and then do a normal equilibrium calculation using partial pressures. Once you have the partial pressure, to find mole fraction divide partial pressure by total pressure (sum of partial pressures).
How can you tell which species is most likely to be a radical?
A radical is a species with one or more unpaired electrons, thus, an substance with an odd number of electrons could become a radical
What would make something a heterogenous vs homogenous catalyst?
- Heterogenous = catalyst is in a different phase than the reactants
- Homogenous = catalyst is in the same phase as the reactants
Which compound would be most effective in catalyzing the saponification of an ester?
Strong base (NaOH)
What is the energy content in kcal of one peanut, if the temperature of 1 kg of water in a calorimeter increases by 50C upon the combustion of 10 peanuts? (Note: For water, the heat of fusion is 1.4 kcal/mol, the specific heat is 4.185 J/g•oC or 1 cal/g•oC, and the density is 1.0 g/mL at 15oC. One kg equals 2.2 pounds.)
(1 kg) × (1000 g/kg) × (1 cal/g oC) × (1 kcal/1000 cal) × (50oC) = 50 kcal but that is for 10 peanuts so divide by 10 to get 5kcal
How do you calculate the number of protons, neutrons and electrons in an element?
- Protons = atomic # = electrons IF neutral
- Neutrons = mass # - atomic #
- Electrons = atomic # - charge
What is the difference between tautomerization and resonance?
- Resonance - only moves electrons around
- Maintains same structure (arbitrary and do not exists)
- lowers potential energy to stabilize the molecule - Tautomerization - moves bonds (atoms or H) around making new functional groups
- Makes structural isomers that interconvert rapidly
- has no stabilization effect
What does red litmus paper detect and what color will it change? and what does blue litmus paper detect and what color does it change?
- Detects whether a solution is acidic or basic
1. Blue turns red under acidic conditions
2. Red turns blue under basic or alkaline conditions - color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F).
3. Neutral litmus paper is purple.
Why does nickle (II) ion produce a green color?
Nickle (II) is green colored because the nickle II ion has a partially filled d orbital and the electrons in the lower energy d orbitals absorb visible light to move to the higher energy d orbitals
when a sound wave crosses the X axis it is considered to be at what point?
Zero displacement
When capacitors are in series how does that effect overall capacitance? what about in parallel?
- Opposite of resistors
1. Series = 1/C1 + 1/C2 + etc
2. parallel = C1 + C2 + etc
What is the function of an ebulliator?
To prevent superheating of the liquid to be distilled
What would improve the degree of fractional separation between two substances?
- Heat the distillation flask at a slower rate!
- Cooling condenser doesnt effect, shortening fractionating column = less separated
- lower pressure inside = decreases BP and will cause smaller difference
What happens if there is a leak in the vacuum distillation apparatus?
- The BP of the two components will BOTH INCREASE
- Vapor pressure of a liquid increases with increasing temp, so BP of liquid decreases as pressure on surface of liquid is decreased
- A leak would cause the surface pressure to increase
What is the bond order between oxygen atoms? in O2
2
- 12 valence electrons with 8 in bonding and 4 in antibonding
- Subtract bonding from antibonding and then divide by 2
What is an isoelectronic compound?
- Have same number of electrons
How can you tell which electrons will have the greatest energy?
- Whichever one has the highest n value because it makes the smallest negative number
What does a trigonal planar bond look like?
AlCl3 bc it is an expection to the octet rule, makes 120 degree angles
What pure substance has the highest bp typically?
Water, based on IMFs
What is a permanent dipole?
- when the dipoles do not cancel out, must have polarized bonds
The H-C-H bond angle in dichloromethane (DCM) is expected to be: A. Greater than 109.5, but less than 120 B. Equal to 109.5 C. Less than 109.5 D. Equal to 120
Less than 109.5 because the steric clashing between the Cl will cause the H’s to be pushed together
What is a conjugated system?
A system that is connected by p orbitals with delocalized electrons in molecules with alternating single and pi bonds
What is the difference between resonace, constitutional isomers, conformational isomers and epimerization?
- Resonace - rearranging of valence electrons from one atom to another
- Constitutional isomers - structural isomers, that have completely differnt functional groups
- Conformational isomers - same molecular formula, same connections but are comprised of bonds that are freely rotatable
- Epimerization - Mutarotation - change in specific rotation of a chiral compound. The sugars ring opens up and rearranges the orientation at the anomeric carbon
What is the difference between thermodyamic control and kinectic control in the formation of compounds?
if something is stable and does not change upon mixing it means it is in kinetic control
- if something changes to a new state it as a preference and is likely in thermodynamic
What would allow a product to be detected with color?
- More conjugated double bonds
How do you determine catalytic efficiency?
Ratio of Kcat/Km
what is the equation for wavelength, velocity and frequency?
wavelength = V/f
When does the ideal gas law not hold true?
- The ideal gas model tends to fail at lower temperatures or higher pressures, when intermolecular forces and molecular size becomes important
- It also fails for most heavy gases, such as many refrigerants, and for gases with strong intermolecular forces, notably water vapor
What is the dopler effect and how does it affect wavelength and frequency of things traveling?
towards you, higher f, higher pitch, smaller wavelength
When using spectroscopy what absorbance color do you want to measure? what are the colors and wavelengths?
- Want to use complementary colors
- Y(560-600) –> V (400-500)
- O (600-640)–> B (450-480)
- R (640-700) –> G (450-560)
How do you determine a Km from a line weaver burk plot
it would be 1/Km which is the X intercept
When looking at concentration graphs, shifting to the right indicates an increase or decrease in stability?
Increase!
How does PAGE and SDS PAGE affect the molecules?
- DOES NOT AFFECT HOMODIMERS!!
- If the dimers are of different molecular weight, THEN they will make different bands, other wise all one band
- Applies negative charge to molecule
What is the difference between a random order mechanism and an ordered mechanism and how can you tell if a ternary complex is formed?
- Ordered mechanism - One thing binds then another binds
- Random - either substrate could bind first
- Ternary because both substrates occupy the catalytic cleft
The oxidation of aldehydes and ketones produces what? the reduction of ketones produces what?
- Oxidation of aldehydes = carboxylic acids
- Reduction of ketones = alcohols
- Oxidation of ketones = cannot be oxidized further! bc C=O bond already possesses two C-C bonds and cannot be broken easily
What is a diol?
Must have two alcohol groups
Which of the following is a plausible scenario for the work of CoQ in the electron transport chain?
A. Coenzyme Q10 is reduced by Complex I and later oxidizes Complex III.
B. Coenzyme Q10 oxidizes Complex I and then is later oxidized by Complex III.
C. Coenzyme Q10 reduces Complex I and later reduces Complex III.
D. Coenzyme Q10 is oxidized by Complex I and is later oxidized by Complex III.
B - read closely
- From the passage we learn that CoQ takes electrons from Complex I and II and passed them to Complex III. Since it takes electrons from Complex I, it is reduced and it oxidizes Complex I. Later, when it passes electrons to Complex III, CoQ is oxidized and reduces Complex III.
What are the common IR regions for the for the following bond types:
- O-H
- C=O
- C=C
- CtriplebondC, CtriplebondN
- O-H (3200-3600)
- C=O (~1700)
- C=C (~1650)
- CtriplebondC, CtriplebondN (2100-2300)
NOTE: C-H is 2950 and will NEVER be the answer
When you have an overall E > 0, how does that effect deltaG?
Means negative delta G
What is the voltage generated by an electrochemical cell at equilibrium?
Voltage must be 0!
What is a spectator ion?
A spectator species is unchanged in the net ionic equation
i.e. appears the same on both sides of the reaction and is not consumed
Before coordination to protoporphyrin, what is the ground state electron configuration of Co2+? A. [Ar]4s23d5 B. [Ar]4s23d7 C. [Ar]3d7 D. [Ar]4s24d5
C! bc During the ionization of transition metals, electrons from 4s subshell orbitals are generally removed before those from 3d subshell orbitals. This is because it is also generally true that, when occupied by electrons, electrons of 4s subshell orbitals are higher energy than those in 3d subshell orbitals.
What is the reaction of carbonic acid and when does it occur?
The combination of CO2 and H2O to make carbonic acid (H2CO3)
- Carbonic acid and its conjugate base (bicarbonate) play a large role in maintaining the pH of the human bod
- Makes pH more acidic!
Under anaerobic conditions, bacteria can sometimes derive energy from the oxidation of sulfur-containing species. Which of the following can NOT be oxidized by anaerobic bacteria? A. H2S (aq) B. SO42- (aq) C. S2O32- (aq) D. S8 (s)
B bc The highest oxidation state for sulfur is +6, corresponding to the loss of all of its valence electrons
What is a 5-8.5ppm peak indicitive of?
Amide hydrogens!
How do surfactants exert catalytic effects?
Reducing activation energy of the reaction
What is KMnO4 used for? what is PCC used for?
KMnO4 - Oxidize alcohols to carboxylic acids
PCC - mild oxidizing reagent when added to a primary alcohol in non-aqueous solution, it converts the alcohol to an aldehyde (KMnO4 gets it all the way to carboxylic acid)
What contributes to the levels of FDG signal seen during a PET scan of the colon?
I. Blood flow to the tissue
II. Availability of oxygen to the tissue
Which of the following is most likely to undergo positive beta decay? A. 14C B. 13C C. 17O D. 22Na
D - Looking for a high proton to neutron ratio!
- Positive beta decay, also known as positron emission,
What does a high and low youngs modulus indicate?
- High - steepest slope = stiffest
2. Low - least steep = not stiff
What is the elastic potential energy equation?
PE (spring) = 1/2kx^2
In order to measure the ∆G, researchers needed to denature the proteins. Which of the following steps would be LEAST suitable for this procedure?
A. Increasing temperature
B. Irradiating the protein with non-ionizing radiation
C. Adding a concentrated chaotropic agent
D. Lowering pH
B - bc nonionizing radiation doesnt break bonds
- Irradiating the proteins with X-rays or gamma rays certainly can denature them, but these are forms of ionizing radiation.
Administration of a muscle relaxant causes a vessel to increase radius by 10%. If all else is held constant, the volume flow rate will change to approximately what percent of the original rate? A. Increase to 150% of the original B. Remain at 100% of the original C. Decrease to 65% of the original D. Cannot be determined
A is correct. Volume flow rate is proportional to the radius raised to the fourth power. An increase of 10% means the rate of flow will increase to 1.14 of the original rate. We need not do any calculations here, since only choice A says that the flow rate will increase.
If the volume flow rate through segment 1 is 3 times that of segment 2, with all else being held constant, what is the value of P3? A. 40 B. 70 C. 80 D. 100
C
A horizontal force of 100 N is applied to a 50-kg box that is accelerating at 1 m/s2 on a rough, horizontal surface. What is the work done by kinetic friction if the box is moved 4 m? A. 0 J B. -150 J C. -200 J D. -400 J
Fnet = ma = Fapplied – Fk, where Fk is the force of kinetic friction.
(50 kg)(1 m/s2) = 100 N - Fk
50 N = 100 N - Fk
Fk = 50 N
To calculate work, we use W = Fd cos θ.
W = (50 N)(4 m)(cos 180º) = -200 Nm = -200 J
What reaction conditions are necessary to react amines or alcohols
Amines and alcohols are not reactive on their own so to add them you need to activate it (heat - dehydrate)
What does calcium sulfate look like? what does calcium sulfite look like?
“Calcium sulfate = CaSO4
Calcium sulfite = CaSO3”
” Another possible method of separating 2-methylundecanal and 2-methylundecanoic acid could be based on:
A. their differences in the rotation of plane-polarized light.
B. a mass spectrometry analysis.
C. an extraction based on their differing solubilities.
D. the very different scent profiles of each molecule.”
C - its the only method of separation, the rest are methods of analysis
“Rank the order of these substances boiling points:
- Alkane
- Alcohol
- Aldehyde
- Acid
- Amide
- Amine
- Ester
- Ether
- Ketone “
“1. Amide
- Acid
- Alcohol
- Ketone
- Aldehyde
- Amine
- Ester
- Ether
- Alkane “
“What are the formal charges on the atoms in the molecule below? (Note: the molecule has not been labeled with overall formal charge and may have an overall formal charge that is 0 or a value other than 0.)
OtriplebondN-O”
(+1, +1, -1)
“The preferred ion configuration of many elements on the periodic table is determined by:
A. the electron configuration of the nearest noble gas; elements will gain or lose electrons until they have the same core electron configuration as this noble gas.
B. the electronegativity of the element directly above it, within the same group; elements will gain or lose electrons until they have an electronegativity that matches the period immediately above them.
C. the electron configuration of the nearest noble gas; elements will gain or lose electrons until they have the same valence electron configuration as this noble gas.
D. the relative stability of the nearest d subshell; elements will gain or lose electrons until the outermost d subshell available is stable.”
“C
- Elements will often adopt a configuration with a complete octet – the configuration found in the noble gases. This complete octet is preferred for the outermost valence electrons.”
” If a 65-kg man undergoes a turning acceleration of 5 m/s2 during a running turn, what is the magnitude of force experienced by the foot due to the ground?
A. 325 N B. 650 N C. 750 N D. 1075 N "
"C - We are looking for the overall force experienced, so we must find the hypotenuse. Specifically, we need to find the hypotenuse of a triangle with legs of Fnormal = mg = (65 kg)(10 m/s2) = 650 N and Fturning = (65 kg)(5 m/s2) = 325 N. The combined vector will be bigger than either component alone, so eliminate choices A and B. To solve, let's round 650 N to 700 N and round 325 N to 300 N. With this in mind, this calculation can be approximated as: √(3002 + 7002) = √(90000 + 490000) = √(580000) = √(58 x 104) = (√58) x 102
The square root of 58 falls between 7 and 8, so the overall value of our answer falls between 700 and 800, meaning that choice C must be correct (the actual value is 761). “
” A book rests horizontally on a table. The book experiences a gravitational force of mg due to the earth’s gravity. According to Newton’s third law:
A. the book experiences a normal force of mg pushing up due to the table.
B. the earth experiences a gravitational force of mg from the book.
C. the table exerts a gravitational force of mg on the earth.
D. the earth exerts a normal force up on the table equal to mg plus the weight of the table.”
“B is correct. Newton’s third law can be expressed as:
FA on B = −FB on A
Here, the force of the earth pulling on the book is equal to and opposite of the book pulling up on the earth. Thus, choice B is correct.
A: Remember that Newton’s third law applies very narrowly to the interactions between two objects. While the table does exert a normal force upwards on the book, that normal force is not what Newton’s third law refers to. Notice that in the equation above, the reaction force of A on B is strictly limited to B on A.
C: The question stem defines mg as the gravitational force on the book. As such, since the book is resting on top of the table, mg would not be the gravitational force exerted by the table on the earth unless the table were entirely massless (which is not stated).
D: This statement, like choice A, is true. However, the question stem is asking for the Newton’s third law corollary to ““The book experiences a gravitational force of mg due to the earth’s gravity.”” The two objects we should be focusing on are thus the book and the earth — not the table.”
”
Nitrogen primarily exists in the atmosphere as a diatomic gas. Which of the following is true about this form of nitrogen?
A. The presence of a lone pair of electrons on each nitrogen atom in the molecule allows it to act as a strong Lewis base.
B. The triple bond of electrons creates a region of high electron density that allows N2 to be very reactive as a nucleophile.
C. Diatomic nitrogen gas is relatively inert and can be used as the atmosphere in laboratory conditions to prevent unwanted side reactions.
D. Atmospheric nitrogen reacts spontaneously with carbon dioxide, which keeps atmospheric CO2 levels at a relatively low 0.04% (on a molar basis) of the atmosphere.”
” C is correct. The MCAT will expect you to be familiar with N2 as a very inert gas. It makes up approximately 80% of the air you breathe, yet has no significant chemical reactions with your lungs – or with anything other than nitrogen-fixing plants. This information implies that nitrogen is very inert (unreactive). As such, it would serve as a good artificial atmosphere when working with reagents that might react with oxygen or other gases.
A, B: Although N2 does have relatively high electron density, the strength and stability of the triple bond means it doesn’t react strongly as many other compounds.
D: Atmospheric CO2 levels are primarily determined by the seasons (when the northern hemisphere enters spring and summer, many plants grow leaves and pull CO2 out of the atmosphere) and by humans burning fossil fuels, which puts CO2 into the atmosphere. Nitrogen and carbon dioxide do not react readily with each other.”
” Which of the following is closest to the bond angle between the carbons in a molecule of acetone?
A. 90º
B. 109.5º
C. 120º
D. 180º”
C
What is the equation for power?
P = V^2/R
What is the function of LiAlH4?
Strong reudcing agent that conversta aldehydes to primary alcohols
” Lathyrism is known to target and degrade collagen in the lower limbs. Which pair of amino acids would best provide disulfide links to stabilize the folded form of collagen?
A. C and C
B. M and M
C. M and C
D. S and S “
A - bc the bond is a S-S bond but S is serine in the amino acids
In the electron transport chain, how are electrons passed between species?
From species with less positive reduction potentials to those with more positive reduction potentials (thus, O2 must have the hgihest standard reduction potential)
When does total internal reflection occur?
”- Total internal reflection can only result when a ray of light begins in a higher-index material and reaches a boundary with a lower-index one (e.g. starting in water and moving towards air).
- ie: start in water n=1.3 move to air n =1 “
” Which of the following correctly describes the orbital hybridization of XeF4 and NH3, respectively?
A. sp3d2, sp3
B. sp3, sp3
C. sp3, sp2
D. sp3d2, sp2”
“A is correct. One quick way to determine the orbital hybridization around the central atom is to simply count up the number of bonds and lone pairs. For example, ammonia has three bonds and one lone pair around its central nitrogen atom, for a total of four regions of electron density. This orbital hybrid therefore needs four orbitals to hybridize: s, p, p, and p. Thus, ammonia is an sp3 hybrid. We can narrow it down to choices A and B.
Next, XeF4 has two lone pairs and four bonds around the central xenon atom. We know this because the central Xe atom has eight valence electrons. It gets four of these eight electrons from the two lone pairs and four from the bonds — one electron from each bond. Alternatively, we could try drawing the Lewis structure of XeF4, knowing that 8 electrons must come from the Xe atom and 7 from each of the F atoms, for a total of 8 + 7(4) = 36 electrons. Drawing XeF4 with Xe as the central atom and single bonds between the Xe atom and each F atom produces a structure with only 32 electrons, so we must add two lone pairs to the central Xe atom.
Two lone pairs and four bonds gives us six total regions of electron density. So we need six hybrid orbitals to hold those electrons: s, p, p, p, d, and d. That’s an sp3d2 hybrid.”
”
The transcription factor AP-1 is a heterodimer consisting of c-jun and c-fos. C-jun and c-fos are soluble proteins that can be localized to either the cytosol or nucleus of a cell. C-jun and c-fos dimerize through a leucine zipper motif. In a leucine zipper motif, every 7 amino acid residues, or 2 full turns of an alpha helix, are leucine resides. Leucine and other amino acids on one face of the helix come together to form an opposite alpha helix that has a similar arrangement of leucine and other amino acids. Which solvent would be LEAST favorable for c-fos/c-jun dimerization?
A. Hexane
B. Ethanol
C. Water
D. Phosphate-buffered saline”A
A
What ist he rate of cation formation through the loss of hydrogen atom related to?
“Directly related to the energy required to remove a hydrogen atom from the compound
- More energy = slower reaction because harder to remove “
What is RSE and what does it tell you?
”- Relative stabilization energy
- The more negative the number the more stabilizition “
” What effect will the addition of a fluorine substituent have on carbocation stability?
A. The fluorine group will be destabilizing because it is highly electronegative.
B. The fluorine group will be stabilizing because it is highly electronegative.
C. The fluorine group will be destabilizing because it has additional lone pair electrons.
D. The fluorine group will be stabilizing because it has additional lone pair electrons.”
A is correct. The first part of each answer describes whether the fluorine group is stabilizing or destabilizing. From Table 1, we see that the fluorine group has an RSE of +2.9 and is therefore destabilizing (eliminate B and D). Next, we must explain this destabilizing influence. Carbocations are typically unstable due to their high concentration of positive charge. If a substituent can contribute some electron density to the carbocation, this positive charge will be “balanced” and the species stabilized. In contrast, electron-withdrawing substituents pull even more electron density away from the carbocation, decreasing its stability further. Since fluorine is destabilizing, and since it is highly electronegative, we can deduce that it must be electron-withdrawing.
What are the units for lift?
pN
What is the equation for frictional force?
Ff=uFn which is equal to the graviational force pulling something down
“If the radius bone of the forearm can take up to 1150 N of force along its axis before fracturing, which of the following is likely to cause a Colles fracture in a 60 kg man?
A. Falling on an arm that makes a 60° angle with the ground.
B. Falling on an arm that makes a 45° angle with the ground.
C. Falling on an arm that makes a 60° angle with the vertical.
D. Falling on an arm that makes a 45° angle with the vertical.”
C
"A patient is asked to throw a dart in order to hit the bullseye in the center of a target 5 m away. If the initial velocity of the dart is 10 m/s at 45° with the horizontal, from a height level with the bullseye, where will the dart hit the target? A. 2.5 m below the bullseye B. 1.0 m below the bullseye C. 0.0 m above the bullseye D. 2.5 m above the bullseye"
“D
– First we need to find the time it will take the dart to travel the 5 m to the target, then we can find out the height of the dart at that time.
- To do this we need the horizontal velocity.
vx of the dart = v0
cos 45 = 10√2/2 m/s
Time to travel 5 m = (5 m)/(10√2/2) = 1/√2 s
vy of the dart = v0
sin 45 = 10√2/2 m/s
Now we can use one of our kinematics equations to find out the height of the dart at that exact time.
Δy = vyt + ½ at2
Δy = 10√2/2 (1/√2) + ½ (-10)(1/√2)2 = 5 + (-5)(1/2) = 5 – 5/2 = +2.5 m
Thus, the dart will impact the target 2.5 m above the bullseye.”
What is the difference between a scalar and a vector quanitity and what are examples?
“1. Scalar - no direction only magnitude
- length, area, volume
- Speed, distance
- Mass, density
- Pressure, temperature
- Energy, work, power
2. Vector - direction plus magnitude - Displacement, velocity, acceleration
- Momentum
- Force
- Lift, drag, thrust
- Weight “
"In a fit of anger, a man unfortunately throws his new phone horizontally out his window with an initial velocity of 16 m/s. If his window is 45 meters high, what horizontal distance will the phone travel before hitting the ground? Assume no air resistance. A. 20 m B. 45 m C. 48 m D. 144 m"
C
What does it mean when the center of mass translates due to torque
moves to a different location, due to rotation
"A medical gurney is on a frictionless inclined plane. If the plane has an incline greater than 0° but less than 90°, the magnitude of acceleration of the gurney down the plane: (Assume that gravitational acceleration has a magnitude of 10 m/ s2.) A. can be 0 m/s2. B. can be any value greater than 0 m/s2. C. can be greater than 10 m/s2. D. must fall between 0 and 10 m/s2."
“D is correct.
- The only force acting parallel to the plane is the relevant component of the gravitational force (the x-component).
- This force is equal to Fgravsin(θ), or mgsinθ.
- Since this is the only force that will drag the gurney along the plane, it is also our net force.
- From Newton’s second law, remember that Fnet = ma. Substituting in our equation yields mgsinθ = ma, or gsinθ = a.”
"A simplified model of a mammalian forelimb is shown below. The forelimb has a uniformlydistributed mass of 2 kg and a length of 30 cm. A downward force of 10 N is exerted at the end of the limb, 30 cm from the point of rotation. What is the magnitude of the upward force that must be exerted 10 cm from the point of rotation to prevent the forelimb from moving? A. 3.3 N B. 10 N C. 30 N D. 60 N"
“D is correct.
- We have two downward torques: that of the 10-N applied force and that of the weight of the board (20 N), which is exerted at the board’s center of mass, 15 cm from the point of rotation.
τtotal downward = (10 N)(0.3 m)(sin 90°) + (20 N)(0.15 m) (sin 90°)
τtotal downward = 3 N∙m + 3 N∙m = 6 N∙m
- The upward torque, then, must also be equal to 6 N∙m.
- We are told that the upward force is exerted 10 cm from the point of rotation, meaning that we can calculate it as follows:
τ upward = F ∙ d ∙ sin (θ)
6 N∙m = (F)(0.1 m)(sin 90°)
6 N∙m = 0.1F
F = 60 N”
What is homotropic regulation?
”- A molecule serves as a substrate for its target enzyme, as well as a regulatory molecule of the enzyme’s activity. O2 is a homotropic allosteric modulator of hemoglobin.
- AKA what gives the sigmoidal shape of oxygen binding curve “
“Fluid pressure changes with depth are assumed to be linear. Which statement best explains why this does not hold true for atmospheric pressure changes?
A. At very high temperatures, air behaves less ideally.
B. The volume of a mass of air is not constant.
C. The majority of molecules in air are nonpolar.
D. Air is not of a uniform composition.”
“B is correct. Hydrostatic pressure for liquids is linear because as depth changes, the density of the liquid remains constant. Gases, however, have densities that change according to the forces applied to them. Gases are compressible, while liquids and solids are not.
A: For gases, higher temperatures result in behavior that is more ideal.”
“While the composition of oxygen and nitrogen in air does not change with altitude, the decreasing temperature at high altitude does change the percent of air that is composed of H2O. Assuming constant relative humidity, which of the following can be asserted about the total grams of H2O in a given volume of air at 3000 m above sea level versus at sea level?
A. Assuming constant relative humidity means that air has roughly the same mass of H2O per unit volume at 3000 m above sea level.
B. Whether air at very high altitude has more or less mass of H2O per unit volume than it does at sea level depends on the temperature at high altitude.
C. Air has significantly more mass of H2O per unit volume at 3000 m above sea level.
D. Air has significantly less mass of H2O per unit volume at 3000 m above sea level.”
“D is correct. With decreasing temperature, air is able to hold less H2O. Since colder air can hold less total H2O, this means the same relative humidity would result in less total water in the air.
For example, if warm air could hold 100 g of water in a given volume, then 50% relative humidity would be 50 g of water in the air. And if cold air could only hold 40 g of water in the same given volume, then 50% relative humidity would be 20 g of water in the air. So with the same relative humidity, the cold high-altitude air has less mass of water.”
“The complete conversion of three moles of glucose by aerobic fermentation yields how many moles of acetic acid?
A. 1
B. 2
C. 3
D. 6”
D
“If a hospital requires at least 250 g of 145Nd to complete a standard cardiac image, how long will it be before it must replace a 2000 g sample if the sample decays to 93% after 100 minutes?
A. 25 minutes
B. 50 minutes
C. 75 minutes
D. 100 minutes
”
“C is correct. The decay of a substance can be calculated by knowing its half-life, the time it takes for half of the original amount to decay. The final paragraph states that about 93% of the decay occurs in the first 100 minutes. This leaves about 7% of the sample left, which would indicate that close to 4 half-lives (0.54 = 0.0625 = 6.25% remaining) have passed at the 100-minute mark. Thus, 1 half-life = 100/4 = 25 minutes. The hospital sample is 2000 g and must be replaced once it reaches 250/2000, or 1/8 of its original radioactivity.
Using the shortcut that the amount remaining = (1/2)n, where n represents the number of half-lives that have passed, we can calculate 1/8 = (1/2)3. Therefore, 3 half-lives will pass before the sample drops below 250 g. At 25 minutes apiece, 25 min (3) = 75 minutes.”
“Which of the following charged particles will be attracted to the particle emitted during the decay of 145Nd?
A. An electron
B. A neutron
C. An anti-neutrino
D. A positron “
D
At what pH is spectrophotmetric absorbance greatest?
“Smallest pH because spectrophotometric absorbance is used to measure the conc of metal ion remaining in aquesous solution following extraction
- This value is maximized when the extend fo the extraction is minimized “
“In oxidative phosphorylation, what is the final step?
A. O2 is oxidized to produce H2O.
B. NADH is oxidized to form NAD+.
C. H+ is hydrolyzed to form H2O.
D. ADP is phosphorylated to produce ATP.
”
D
“A 50-kg child is riding on a playground merry-go-round. If the radius of the circular path of the merry-go-round is 5.0 m and the frequency is 0.1 hertz, what is the force required to keep the child on the ride?
A. 25 N
B. 100 N
C. 1000 N
D. 2500 N
”
“B is correct. If the frequency of the merry-go-round is 0.1 Hz, then the period is 10 s. We can calculate the speed of the merry-go-round from V = 2πr/T = 2(3.14)(5.0 m)/(10 s) = 3.14 m/s. Using this in the centripetal force equation:
Fc = mv2/r = (50 kg)(3.14 m/s)2/(5.0 m)
Approximate the square of the speed at 10 m2/s2.
Fc = (50)(10)/(5) = 100 N”
What is a suicide inhibitor?
”- Suicide inhibition occurs when an enzyme binds the inhibitor (structurally a substrate analogue) and forms an irreversible complex with it, usually through a covalent bond.
- This can involve the inhibitor being chemically modified by the enzyme during the normal course of catalysis to produce a reactive group that is specifically responsible for the formation of the irreversible inhibitor-enzyme complex.”
What is the difference between an imine, amine, amide,
“1. Amines are derivatives of NH3
- Amides are acid derivatives (or more rarely, anionic amines)
- (i) the acid derivative, R C ( = O ) N R 2 , or (ii) the conjugate BASES of ammonia, for instance potassium amide, K N H 2 , which is unknown in aqueous solution, but known in liquid ammonia - Imines are nitrogen derivatives of carbonyl compounds.
- R C ( = N R ‘ ) R , formed by condensation of a carbonyl and an amine:”
What does the pKa correspond to on a titration curve?
The half equivalence point on a titration curve
What is the equation for mechanical advantage and what are the ratios sides of a 30-60-90 triangle?
“MA = hypotenuse / height
a 30º-60º-90º right triangle, with side ratio of x : x√3 : 2x. Thus:”
“Gurney 1 has a dummy placed on it to give it a total mass of 200 kg, while Gurney 2 is loaded with a dummy that makes it only 50 kg overall. If the ramp has a coefficient of friction of μs, which gurney is more likely to slide down the ramp?
A. Gurney 1, due to the increased force of gravity
B. Gurney 2, due to the reduced force of static friction
C. Gurney 1 and Gurney 2 are equally likely to slide.
D. Neither gurney can slide unless the wheels are unlocked.
“
C is correct. In order for the gurney to slide down the ramp, the force pulling it downward (mgsinƟ) must be greater than the static frictional force (μsFN = μsmgcosƟ). The net force on each gurney is thus Fnet = (mgsinƟ) - (μsmgcosƟ). Since net force is equal to the product of mass and acceleration, we can rewrite this equation as ma = (mgsinƟ) - (μsmgcosƟ), where an acceleration greater than 0 means the gurney will slide down the ramp. The mass of the gurney is present in all terms and can be canceled, meaning that it is not a factor in whether the gurney slides. Thus, both gurneys have an equal likelihood of slipping down the ramp, regardless of the fact that they have different total masses.
"What is the approximate pH of a saturated aqueous solution of hydrochloric acid whose molarity is 10.6 M? A. -1 B. 1 C. 7 D. 13
”
A is correct. Hydrochloric acid is a strong acid and completely dissociates in aqueous solution. In this solution, the hydronium ion concentration is 10.6 M, which can be approximated as 10 M to make the math easier. The pH is the -log of the hydronium ion concentration: -log[10] = -log[101] = -1. While the typical pH range is normally thought of as ranging from 0 to 14, if the concentration of hydronium ion is greater than 1 M, negative pH values are possible. It is also possible to have pH values greater than 14, i.e. if the hydroxide concentration is greater than 1 M.
Which molecules will have the highest Rf value when studied with thin-layer chromatography using a silica plate?
”- Silica is highly polar
- Something that is nonpolar will move faster (larger Rf) “
What is the difference between an ester and a ether?
“1. Ester - RCOOR’. Esters are made by the reaction between a carboxylic acid with an alcohol.
2. Ester - two alkyl groups, aryl groups, or an alkyl and an aryl group are connected to both side of an oxygen atom(ROR’)”
Which type of synthesis proceeds from the C terminal to the N terminal and which type proceeds from the N terminal to the C terminal?
“1. C terminal to N terminal - Solid phase peptide synthesis
2. N terminal to C terminal - Ribosome protein synthesis (more common) “
What are the traits of benzene that make it good for reactions?
“1. Inert to acids and bases
- aromatic hydrocarbon
- very stable “
“An artificial heart valve was tested for its ability to function under extreme conditions, to a maximum flow rate of 4.00 x 10-4 m3/s. What speed would this correspond to for an average red blood cell within a blood vessel of cross-sectional area 5.00 x 10-6 m2?
A. 2.00 x 10-9 m/s
B. 1.25 x 10-2 m/s
C. 4.05 x 10-4 m/s
D. 8.00 x 101 m/s
”
“D is correct. Watch your units! We’re given one number in m3/s and another in m2. To get an answer in the units of m/s, just divide the two numbers in the question:
Speed = (4 x 10-4 m3/s) / (5 x 10-6 m2)
= (4/5) x (10-4/10-6)
= 0.8 x 102 m/s
= 8 x 101 m/s
This can also be solved using the equation flow rate = cross-sectional area x velocity.”
“A man is accidentally exposed to a toxin which binds irreversibly and noncompetitively to pyruvate dehydrogenase. A likely consequence of this ingestion is:
A. a decrease in lactic acid concentration in exposed cells.
B. an increase in the concentration of acetyl-CoA in exposed cells.
C. a decrease in the level of Krebs cycle activity within the exposed cells.
D. an increased rate of formation of NADH in exposed cells.”
“C is correct. Pyruvate dehydrogenase is the enzyme that mediates pyruvate decarboxylation. This step is the critical link between anaerobic and aerobic respiration. With this link broken, cells would be limited to anaerobic respiration. Thus, a decrease in aerobic respiration makes sense in this context.
A: Lactic acid is a byproduct of anaerobic respiration. With pyruvate decarboxylation blocked, the cell would likely see an increase in such products.
B, D: Acetyl-CoA and NADH are products of pyruvate decarboxylation. Blocking this enzyme would lower these concentrations.”
“If elements in the same group of the periodic table tend to have similar chemical properties, which of the following is the most likely structure of hydrogen sulfide?
A. Tetrahedral
B. Trigonal planar
C. Pyramidal
D. Bent”
“D
- Group 16, directly under oxygen, so the structure of hydrogen sulfide would be similar to that of water: bent. The Lewis dot structure of H2S also predicts a bent structure due to the presence of the two lone electron pairs on the sulfur atom.
A: Neither hydrogen sulfide nor water is tetrahedral. A common example of a tetrahedral molecule is methane (CH4).
B: Trigonal planar molecules have three substituents bound to the central atom, which is not true of hydrogen sulfide. Boron trifluoride (BF3) is a good example of a trigonal planar species.
C: Hydrogen sulfide is not pyramidal. One of the most common examples of a trigonal pyramidal structure on the MCAT is ammonia (NH3).”
“Ritonavir is an antiviral drug that mimics the natural substrate for a key viral protease enzyme. As a competitive inhibitor, ritonavir:
A. decreases the rate of reaction because it decreases the availability of ATP to catalyze the reaction.
B. increases the rate of reaction by altering the tertiary structure of the enzyme.
C. decreases the rate of reaction by binding to the enzyme and altering the structure of its active site.
D. decreases the rate of reaction by binding to the active site.”
D is correct. This question is asking us for the definition of a competitive inhibitor, which binds to the active site and blocks the substrate from attaching. The mechanism of a generic competitive inhibitor is depicted below.
How does recrystalization work and what does MP tell you?
”- Recrystalization works by having a solvent that makes the product of interest highly soluble in warm temperatures and insoluble in cold.
- The MP tells you the purity (ie: if its close to what you want its likely more pure)
- If a compound is always insoluble then it will never dissolve and cannot recrystalize
- if comppound is always soluble then we cannot reform the desired solid even when we have cooled the solvent “
What is the difference between vacuum distillation, simple distillation, and fractional distillation?
“1. Vacuum distillation - used when you have compounds with high BP to help lower the ambient pressure to make them more prone to vaporization
- AKA temps that are hard to get in lab
2. Fractional distillation - use when you have compounds with a BP difference less than 50 - CANNOT be used to separate solvent from solute
- DO have to repeat to purify
3. Simple distillation - used when compounds with BP difference GREATER than 50 - CAN be used to separate solvent from solute
- DONT have to repeat to purify “
How does IR spectroscopy measure absorbance?
- Absorbance is measured as a function of the incident energy that is absorbed directly into the chemical bonds
What type of analysis would be used to anaylze a small organic ligand binding to its receptor?
NMR?
Why is SDS a useful reagent for gel electrophoresis?
“I. SDS confers a uniform charge density to all proteins in the sample.
- Long hydrophobic tail
II. SDS is amphipathic, allowing it to denature most globular proteins.”
What environment can cytosolic proteins not unfold in?
”- Highly charged environments because they are hydrophobic globular cytosolic proteins
- Would case transmembrane proteins to denature “
What does UV-Vis typically assess for?
“The presence of highly conjugated systems
- ie: double bonds or triple bonds “
In gel electrophoresis with SDS PAGE, what do the charged proteins migrate towards and what is their charge?
”- Negative charge
- Migrate towards the anode WHICH is (+) in electrophoresis! (cathode is -) “
What are the SI units for length, mass and time?
The SI units for length, mass, and time are often described as “MKS units,” or meters, kilograms, and seconds
For a velocity vs time graph, an upward linear slope is indicative of what?
- Shows that the velocity is increasing
“Several manic gorillas are throwing objects from a skyscraper. At the exact same instant, one of the gorillas drops a 15-kg table directly downward, another throws a 20-kg refrigerator horizontally with a velocity of 10 m/s, and a third drops a 1-kg lunchbox straight down. If air resistance can be neglected, which object will hit the ground last?
A. The table, due to its larger mass and negligible initial velocity
B. The refrigerator, due to its substantial horizontal velocity
C. The lunchbox, due to its smaller mass
D. All three objects will reach the ground at the same time. “
D is correct. Time in flight does not depend on mass; in other words, if two objects of different masses are simultaneously dropped from the same height, they will hit the ground at the same time. Additionally, though the refrigerator is thrown horizontally while the other two objects are dropped, all projectiles begin with a vertical velocity of zero.
“A slingshot propels a rubber ball horizontally from a platform 30 m off the ground at 15 m/s. Approximately how far from the base of the platform will the ball land?
A. 14 m
B. 21 m
C. 30 m
D. 38 m “
“D is correct. Let’s start by listing our known values. The height of the platform, or vertical distance, is 30 m. The initial velocity is 15 m/s, but remember that this is entirely horizontal! The initial vertical velocity is 0 m/s and the gravitational acceleration can be estimated at 10 m/s2.
First, use vertical components and the equation Δx = v0t + ½at2 to find time. 30 m = ½(10 m/s2)(t2) means that t2 = 6, so t ≈ 2.5 (you should know that the square root of 4 is 2 and the square root of 9 is 3; so the square root of 6, which is between 4 and 9 should be between 2 and 3; just estimate that as 2.5).
Next, use horizontal components to find range, which is equal to the product of initial horizontal velocity and time. Range = (15 m/s)(2.5 s) = 37.5 m. That’s closest to choice D.”
What is the equation for finding horizontal distances along a plane?
vf2 = vi2 + 2aΔx
“Compared to the moon, Earth is about 100 times more massive and has a radius about four times larger. By what factor is the gravity on Earth greater than that experienced on the surface of the moon?
A. 2
B. 6
C. 16
D. 100 “
B is correct. To answer this question, we must remember the equation Fgrav = GMm/r2. Since Earth has a mass that is 100 times that of the moon and a radius that is four times the moon’s radius, it will have an Fgrav that is (100)/(42) = (100/16) times greater. This fraction is closest to 6.
When trying to find the final velocity of an object (mass m) on a ramp (h tall with L length) with friction (uk) what is the equation?
The kinetic energy at the end of the track is equal to the initial potential energy (mgh) minus the energy lost to friction. Since that dissipated energy is the same as the work performed by the frictional force, it can be written as µkmgL. In other words, ½ mv2 = mgh – µkmgL.
What are newtons 3 laws?
“1st - objects at rest will stay at rest and objects in motion will stay in motion as long as no net force is acting on it
2nd - F=ma
3rd - for every reaction there is an equal and opposite reaction “
When solving for the tention in the ropes for objects that are not centered (ie: one rope is longer than the other), which component must be equal and opposite?
The horizontal components of the tension force
How do you determine the coefficient of static friction?
u = Fgrav/Fnormal
For an object moving in a circle, where is the force pointed and how does this effect the work?
”- Always pointed towards the center of the circle
- Velocity vector points at tangent from the circle so angle is 90 which means 0 work is done “
What is the equation for finding weight in a circular path?
Mg + Mv2/R (Combo of centripetal force and gravity)
A metal box with a glass bottom slides down a steep incline. The incline can be assumed to be frictionless, and no air resistance acts on the box as it slides. However, a substantial amount of gravitational potential energy is converted to kinetic energy. How are total energy and mechanical energy conserved? (ie: are they both consereved, neither, or only one)
”- Total energy and mechanical energy are both conserved.
- If friction and air resistance do not affect this process, we can assume that all forces involved are conservative. (The fact that gravitational PE is converted to KE is irrelevant, and happens whenever an object falls or slides downwards.) In cases like this, (KE + PE)initial = (KE + PE)final, so mechanical energy is conserved.
- TOTAL energy is ALWAYS conservered”
The SI unit for power, the watt, is equivalent to one joule/s. This unit can also be written as:
(kg∙m2)/s3.
What are the units for Power and how do you calculate the amount of work that is done?
J/s and you multiply by the seconds
“Which fundamental law of physics prohibits an engine from having an efficiency that is greater than 100%?
A. The first law of thermodynamics
B. The second law of thermodynamics
C. The theory of special relativity
D. No law; this is just a current obstacle related to modern technology. “
A is correct. It is the first law that states that energy cannot be created or destroyed, only converted between forms. In other words, we cannot possibly obtain a larger energy output than was originally supplied. Such a scenario would be required to yield an efficiency of greater than 100%.
What is the equation for work that involves pressure? and what is the conversion for 1L-atm to J?
“Work = PdeltaV
- Conversion = 101.325”
How does an objects moment of intertia effect its translational velocity?
An object’s moment of inertia contributes to its rotational kinetic energy. Since a higher moment of inertia correlates to a higher rotational KE, it also means that translational KE must be lower, as the sum of these two values must equal the potential energy at the top of the incline. For the sphere, more of its mass is concentrated towards the center than for the hoop.
How does hydrogen bonding effect the boiling point of a liquid?
- Hydroxyl groups can hydrogen bond, thus if there are more present then the hydrogen bonding INCREASES the BP of a liquid
Why woud saponification of a triacylglycerol result in four different fatty acid salts?
- One of the fatty acid salts was unsaturated, and a small percentage isomerized under the reaction conditions.
- If one of the R groups in the triacylglycerol contained a carbon–carbon double bond and if isomerization of the double bond occurred during the saponification reaction, four fatty acids would be obtained instead of three.
What makes nitrogen very unreactive?
- Its triple bond!
- Not polar (bc N’s are identical)
What is the difference between molecular and empirical formulas?
- Molecular - actual composition of the molecule (C6H12O6)
2. Empirical - Relative # of atoms of each element it contains (CH2O)
What are the requirements for STP vs sandard conditions?
- STP = 1atm, 22.4L, 0C
2. Standard conditions = 1 atm, 25C, solutions are 1M
What does the volume of a gas depend on as temperature changes?
- Depends only on the # of moles of gas present, not the identity of the gas
What is the geometry of the hexafluoroaluminate ion (AlF63–)?
Octahedral
- An ion consisting of a central metal ion and six ligands is expected to have an octahedral geometry.
What is the difference in arrhenius, bronsted and lewis acid and bases?
ACIDS
- Arrhenius - H+ in H2O
- Bronsted - H+ donor
- Lewis - e- acceptor
BASE
- Arrhenius - OH in H2O
- Bronsted - H+ acceptor
- Lewis - e- donor
What is the difference between a galvanic and an electrolytic cell?
- Galvanic cell converts chemical energy into electrical energy
- Electrolytic cell converts electrical energy into chemical energy
- BOTH - flow from anode to cathode
What do the following reaction types do to an unsaturated fat? A. Acetylation B. Hydrogenation C. Elimination D. Substitution
A. Acetylation - Adds more C-C
B. Hydrogenation - Adds Hydrogen to a C-C multiple bond
C. Elimination- create additional C-C bonds
D. Substitution - Add something in (doesnt change saturation)
How do estrogen and progesterone effect milk production?
High levels of estrogen and progesterone inhibit the production of milk
- Levels drop after birth to help stimulate milk production
What is the function of these enzymes? A. Pepsin B. Amylase C. Hexokinase D. Lactase
A. Pepsin - Hydrolysis (breaking) of peptide bonds to make smaller peptides and AA
B. Amylase- Hydrolysis of starches to sugars (produced by salivary glands and panceas
C. Hexokinase - Phosphorlyation of sugars
D. Lactase - hydrolysis of lactose to glucose and galactose
What structures are disrupted when something is denatured?
Secondary, tertiary (and by default quaternary)
When a solution is supersaturated and perturbed what happens?
Cyrstalization (precipitate) out of solution
What are the requirements of an aromatic ring?
- Cyclic
- Planar
- Conjugated
- Obeys Huckel’s rule (# of pi electrons satisfies 4n+2 rule –> n = 0 or any positive integer, n = number of pi electrons)
How does a magnetic field effect velocity and direction of a particle?
The magnetic field can only change the direction not the speed (how fast its moving)
- the velocity can change but the speed cannot
What are the requirements for a furan?
- heterocyclic
- 5 membered aromatic ring
- 4 carbon atoms and one oxygen
When do substances move into the water layer in extractions and what can make this happen?
- When they become charged
- Adding base to mixture = deprotonate the strongest acid = it will separate out
- Adding acid = strongest base
When attempting a substitution, when should you use a nonpolar solvent and when should you use a polar solvent?
- nonpolar solvents are more effective when attempting monosubstitution
- polar solvents are typically used for polysubstitution.
What are the following made up of? A. Lactose B. Maltose C. Sucrose D. Lactulose
A. Lactose - Glucose + galactose
B. Maltose- 2 glucose
C. Sucrose - fructose + glucose
D. Lactulose - Galactose + fructose
What is the difference between fructose and glucose
fructose is 5 membered ring with 2 CH2OH and glucose is 6
How is the glucose monomer connected in the following? A. Lactose B. Maltose C. Sucrose D. Lactulose
A. Lactose - beta anomer (beta acetal linkage to galactose) All others have alpha linkages B. Maltose C. Sucrose D. Lactulose
What is a benedicts test?
- test to indicate reducing sugars
- Reduces all monosaccharides (such as fructose or lactose) and some disaccharides
- Tests for presence of hemiacetals
- (AKA + benedicts test = brownish red precipitate)
What makes ketals excellent protecting groups?
- Extremely resistant to Nu attack under basic or neutral conditions
- This is bc the alkoxide ions constitute relatively poor leaving groups
Testosterone and estrogen, two hormones with roles in the reproductive system, are classified as derivatives of what?
Cholesterol
- All steroid hormones are derivatives of cholesterol
- In general, steroid hormones can be distinguished from peptides by their suffixes, which tend to be either “-ol,” “-one,” or “-en.”
How do you name a fatty acid?
- Start numbering carbons at carbonyl
- Prefix is from total # of carbons with -oic acid always used as suffix
- For unsaturated fatty acids you must say cis or trans
- location of double bonds identified using lower #
- TRIEN is inserted between prefix and suffix to show the alkenes present
Typically, the dissolution of a lipid in water is highly unfavorable. With this in mind, the entropy change associated with dissolving a phospholipid in aqueous solution is
A. more negative than the entropy associated with dissolving a cholesterol molecule.
B. more positive than the entropy associated with dissolving a cholesterol molecule.
C. more positive than the entropy associated with dissolving inorganic phosphate.
D. more negative than the entropy associated with dissolving a triacylglycerol.
B is correct. Phospholipids are amphipathic, meaning that they contain both hydrophobic and hydrophilic regions. For this reason, a phospholipid will interact more favorably with water than will entirely hydrophobic molecules such as cholesterol or triacylglycerols. A positive (or less negative) change in entropy is a hallmark of a more favorable dissolution. In other words, since the solvation of a phospholipid is more favorable than the solvation of a cholesterol molecule, it will have a more positive entropy.
What is the equation for observed angle of rotation?
enantiomeric excess = (observed optical rotation * 100) / (specific rotation)
In a unimolecular Nu substitution reaction, how does the solution rotate plane polarized light if it intiially rotated it in a clockwise direction
- Wont rotate at all because in an SN1 reaction, the original stereochemistry of the molecule is lost when the carbocation intermediate (a planar structure) is formed. Thus, the product is present as a racemic mixture. Such a mixture includes each enantiomer in a 1:1 ratio, meaning that it promotes no net rotation of polarized light.
- If it had been SN2 it would have been opposite
How do you determine the number of stereocenters a molecule will have?
2^n
What is the difference between
A. conformational isomers.
B. structural isomers.
C. geometric isomers.
D. enantiomers.
A. conformational isomers - based on rotation around a single bond
B. structural isomers - share molecular formula but have different bonding configurations
C. geometric isomers - Presence of double bond or ring
D. enantiomers - stereoisomers with one center changed
