MCAT Chem Phys Flashcards
1
Q
What is the normality of a solution? How would you find the normality of a solution?
A
Normality–> number of moles of protons per liter of solution. It can be calculated by 1) molarity x number of moles or 2) molarity x number of protons in solution.
2
Q
What happens to the pH/pOH of water as the temperature first increases, then decreases?
A
As temperature rises, the pH of water increases (becoming more basic).
3
Q
What is the equation that allows you to find the concentration (molarity, volume, or weight) of substance needed to neutralize a solution?
A
When finding concentraitons of an Acid or Base in a problem, try to apply NV=NV to find volume and mass of whatever youre looking for.
4
Q
What equation is used to measure the force exerted on an object in an electrical field?
A
F=Eq Know how to convert units correctly!!
5
Q
What is the equation for Tension?
A
Equation for Tension is T=rFsin(θ)
6
Q
What are the effecting factors in bond angles? Are they a set number with no give or can they fluctuate at all?
A
Bond angles are generally set in stone with the exception being when large molecules–or molecules that are very electronegative–cause steric hindrance within the molecule which affects bond angles slightly.
7
Q
If current in a circuit changes, does anything else change?
A
V=IR! When Current changes, resistance does not (it’s a constant) but Voltage would change.
8
Q
What is the equation to measure work done by a parallel plate capacitor?
A
Equation to find work done by a parallel plate capacitor is: W=1/2CV^2
9
Q
What is something all current carrying wires produce and would most accurately measure that current: 1) heat 2) Force 3)magnetic fields or 4)EMF ?
A
All current-carrying wires produce a magnetic field, the strength of which is in direct proportion to th strength of the current. All other answers help determine things about the current but are either not as accurate or do not provide as great of detail and magnetic field.
10
Q
What are the SI units for Conductance?
A
Units for condeuctance or conductivity are C^2 * s /kg * m^2
11
Q
How do dielectric materials affect a capacitor, its voltage, and its electric field?
A
Dielectric materials are placed between capacitors to decrease voltage, decrease the electric field, which leads to an INCREASE in capacitance. This can be related through the equations V=Ed and C=Q/V. As distance decreases, Voltage and electric field also decrease, which raises capacitance.
12
Q
What equation is used to find the energy emitted by a photon?
A
The best equation to use to find the energy emitted by a photon is E=hc/λ
13
Q
If you doubled the mass of a pendulum, how would that affect its final height and velocity?
A
Periodic motion can be described as KE=PE. Mass is independent of final height.
14
Q
What is Huckel’s Rule and how do you use it?
A
Huckel’s Rule–> To find if something is arromatic, use the equation 4n+2=# of electrons and solve for n. If it’s an odd number–like 1.5 or something– its non-arromatic.
15
Q
What are Geometric Isomers?
A
Geometric isomers–> Refers to Cis or Trans configuration (possibly E and Z).
16
Q
What are sturctural isomers?
A
Structural Isomers–> Are the same structural formula but in a different conformation (i.e. butane vs sec-butane).
17
Q
What are constitutional isomers?
A
Constitutioal Isomers—> The same amount of molecules but arragned in a completely different manor.
18
Q
What are the differences between Amines, Enamines, and Imines?
A
Amine–> Just a normal NH2 group attached to something.
Imine–> is a C=N carbon-nitrogen double bond. Enamine—>Is a C=C-NR bond where a nitrogen group is bonded to double-bond carbon.
19
Q
How can we relate kinetic energy to temperature?
A
This equation shows that temperature is porpotional to kinetic energy KE=3/2kT
20
Q
What is the Cathodes functions–and does it difer–between galvanic and electrolytic cells?
A
The Cathode end of the cell is ALWAYS going to reduce no matter what type of cell that it is.
21
Q
What is the equation for Poiseuille’s Law?
A
The equation for Poiseuille’s Law is: Q=(πPr^4)/(8ηL)
22
Q
What method would you use to attempt to separate 2-methylundecanal and 2-methylundecanoic acid?
A
You could easily separate these two based off of their soluability. 2-Methylundecanal and 2-methylundecanoic acid are non-polar and polar respectfully. If the carboxylic acid was deprotonated, it would be very easy to separate the two compounds in water, for example.
23
Q
If an object weighing 10kg is dropped from 20m, what is the maximum speed achieved?
A
First, use PE=mgh, then use KE=1/2mv^2 and solve for v. Answer is 20m/s
24
Q
Using a mechanical force test, what’s the distance from the ankle joint to the force applied? (F=98N and τ=13N/m)
A
Use the equation for torque (τ=rFsin(θ)) to find the radius (solve for r, obviously) Answer=133mm
25
During an anterior draw test, the joint translation occurs at 0.2 s. What is the average velocity of the translation? (translation is 5.7mm)
Literally, just v=d/t, which equals 2.85x10^-3 m/s
26
If you had a 12V battery and four identical resistors in parallel (each 16 Ohms), what is the power dissipated in the circuit?
Add up 1/R=1/4 then use the equation P=V^2/R. Answer is 36W
27
What is the angle of incidence equal to?
The angle of incidence is equal to the angle of reflection (not refraction)!
28
What has a longer bond length: H2S or S2Cl2? Why?
Due to the size differences, S2Cl2 will have a longer bond length due to their large sizes.
29
What is the difference between electron geometry and molecular geometry?
Electron geometry has to do with strictly where the electrons will be in space (think orbitals) while molecular geometry is how the molecule will orient itself (usually not including electrons).
30
How do you determine what is an oxidant and reductant?
An oxidant is something that gets reduced, but a reductant is something that is oxidized (remember Oil Rig)
31
Which ion is smallest: Mg2+, Cl-,F-, or Na+?
Atomic radii decreases, from left to right, across a period. (So it’s largest going down a column and from right to left across the table). However, once you reach anion radii, they become much larger. Mg2+ is the smallest.
32
What type of images do Convex mirrors create? What is the radius of curvature of these images?
Convex mirrors create virtual images and the radius of curvature is 2f (two times the focal length).
33
What is the difference between closed and isolated systems?
Closed systems DO NOT exchange matter, but CAN exchange heat. However, isolated systems CANNOT exchange either.
34
What is the equation to find frictional force?
Equation for Frictional Force: F=M*g*sin(θ)
35
What is the equation for Buoyant Force?
F=ρ*V*g (density*volume*gravity).
36
What is Reynold's Equation?
Re=ρvd/μ
| Density)*(volume)*(length) / (new
37
What is the Pauli exclusion principle?
Electron spin is opposite of each other
38
When asked about the energy of a falling object, what equation would you use to find either--or both--PE or KE?
The equation PE=KE will allow you to solve for height or velocity.
39
If you had a sample of CO2 at 1 atm and 273K, how would you find volume?
Well, it's probably STP, which means its volume would be 22.4L.
40
If I have to radioactive elements, X and Z (they weigh roughly the same amount), with their half-lives being 12 months and 3 weeks, respectively. In two years, how much will the ratio of atomic mass have changed between the two?
HA! It's a trick question! Even if a great amount of decay happened, the total atomic mass would not have changed any significant amount even though the half-lives differ drastically. So, it's still a 1:1 ratio.
41
Which type of electromagnetic radiation would have the shortest wavelength: sp, sp2, or sp3? Why?
The closer electrons are to the nucleus, the more energy it will take to eject them. Therefore, the sp hybridized orbital will create electromagnetic radiation with the shortest (most powerful) wavelength.
42
What are the four kinematic equations?
1) Vf=Vi+at
2) V^2=V^2+2(a)(d)
3) Xf=Xi(t)+1/2(a)(t)^2
4) Xf=Xi+(v)(t)
43
Define elastic and inelastic collisions and their differences.
Elastic collisions bounce directly off of each other and KE and momentum are conserved. Inelastic collisions are when they stick together and so KE is converted into another energy, but momentum is always conserved!
44
What molecules/compounds have Van der waal and London dispersion forces acting upon each other?
All molecules/compounds that have poles. So, all of them.
45
If you were given a capacitor with a given area, and distance between the plates, how would you find its capacitance and voltage?
First, find the space between the plates using: C=ε(A/d) [ε=9*10^-12 F/m] to find capacitance. Multiply C by dielectric constant to find C2. Then use C1V1=C2V2 to find other voltage.
46
What is the minimum frequency for ultrasound?
Anything above human hearing. So, anything above 20kHz
47
Where are the enzymes located--inside of the cell--that help convert pyruvate into glucose?
In the cytosol and the mitochondria.
48
How would you find the energy efficiency of an engine?
Finding the energy efficiency of an engine uses the equation: η=1-(Qh / Qc) [That is, energy out divided by energy in].
49
How would you find the normality of phosphorus acid? (0.015 M solution)
Well, phosphorus acid is H3PO4. So, we multiply its' protons by the molarity (0.015 M)(3 protons) = 0.045 M Normality. Normality measures the number of equivilant reactants per liter (eq/L).
50
A 50kg child is spinning on a merry-go-round, the radius is 5m, and frequency is 0.1 Hz. What is the child’s’ force upon the ground?
V=2πr/t (Velocity)=2(pi)(radius) / (time). Using that we find velocity, then we use the equation F=mv^2/r . Answer is 100N
51
So, if given a diverging lense, the focal length, and the object length, how would you find where the image would appear?
First, we have our equation 1/f = 1/i + 1/o (this is inverse of focal length equals inverse of image length, plus inverse of object). Then, after finding image length (i), use the equation m=-(i/o) to find the answer.
52
Where--on a UV/IR spec would we look for peaks to determine the most important compositions?
There are mainly just two things we care about here: 1) OH and NH bonds located between 3600-3000 and 2) C=O bonds between 1750-1650. (C=N and C=C are 1700-1600).
53
If a laser shines through a tube and is totally reflected back into the tube--without any exiting--what most be true regarding the angle?
With full internal reflection, θ1 will be equal-to-or-greater-than θ2. This creates total internal reflection. With partial reflection, θc
54
Which environment will have better solubility: a cold environment or a hot environment?
Cold environments have better solubility.
55
How would you find the solubility of a compound?
Given a chemical equation, Ksp=[X]^2 2[Y], for example, set Ksp equal to the compounds. It should like like Ksp=2x^2 or something then solve for x (usually the Ksp of the entire solution is given to you too).
56
What factors, if any, can alter Ksp?
The only factor that can alter Ksp is temperature. Changing the concentration will NOT alter Ksp!
57
What is the difference between sublimation and deposition?
Sublimation is when something goes from solid to a gas form. Deposition is when something goes from gas to solid.
58
If a solution is titrated half way (at its' equivalency point) what is the pH or pKa?
At half-equilvancey point, pH=pKa!
59
If one fan can yell at 82dB, how loud can 10,000 fans yell from the same distance?
Adding 10,000 fans would be increasing the intensity 10^4, which corresponds to 40dB; with the power or 10 being the amount of decibels it rises by.
60
A graph depicting the change in potential energy (PE), will that be in terms of exergonic or exothermic? Why and what is the difference between the two?
This graph will be speaking in terms of exergonic (a decrease in energy to a more stable state), rather than exothermic, which is describing a change in temperature state.
61
If one molecule has two OH groups while the other has two SH groups, which will have a lower pH and why?
The molecule with the SH groups will have a lower pH. Its conjugate base is more stable, therefore, it will have a stronger acid.
62
Out of these options, which is LEAST likely to change when light travels from media (n=1) to a second media (n=1.33): 1) frequency 2) wavelength or 3) velocity ?
Frequency will not change traveling between media
63
How do you tell the difference between α and β glucose anomers?
Beta will always have the --OH group pointed up on C1, while the Alpha anomer points down on C1.
64
Given a sucrose polymer, if you used acid hydrolysis (with a weak base), and Tollen's reagent, what would be the product of this reaction?
Well, the acid hydrolysis would break up the sucrose into glucose and fructose. Then Tollen's reagent would reduce the glucose, producing a silver mirror-like substance.
65
How close is an electrode from a point of conduction? (Given info: Travels 100 m/s over 1 msec)
First, think of what units you need to end with... Need to end with meters. So, how will that happen? Multiply 100 m/s by 1*10^-3 and we get .1 meters.
66
What info about an axon is required to find out its pulse? (Hint: It's 3 things)
Think of Ohm's law I=V/R. So, you will need Potential, resistance per unit length, and length.
67
In this reaction, what role does NADPH play? Oxidizing, reducing, a catalyst, or other? NADPH + H+ + O2 + R–H → NADP+ + H2O + R–OH
In this reaction NADPH is reducing Oxygen so it's a reducing agent!
68
What is the minimum information required to complete an ultrasound? (Hint: Think of the Doppler Effect).
The speed of sound, the frequencies of both sound waves emitted and observed!
69
How woul you figure out the units in this rate reaction? R=k[X]
Well, R must always equal M/s (molar per second) and the concentrations (if first order) will just be M (molar). So, M/s = M in this case. To solve, we would need s^-1 so that we would only be left with M/s = M/s which is the answer! Remember, we're always trying to make M/s = M/s
70
How would you find the pI of an amino acid with just a graph with the titration curve(s) on it? (Example: A basic triprotic acid)
Well, because it's triprotic, it will have 3 equivalency points. To find the pI we take the averge pH between the two most basic equivalency points and divide by 2. To find the pHs, just find where the half-equilvalency points are becuase pH=pKa at the half-equilvancey points.
71
If a 40kg child was running then fell at a 60 degrees from the ground. There KE while falling was 720 J directly before impact. What was their velocity when they were pushed?
This is a little tricky. First, set KE=1/2 * m * v^2 and solve for velocity. Once solved for velocity WE ARE NOT DONE. We get 6 m/s, but because of the angle, we need to find the horizontal velocity. To do that, we need cos(60) * 6 m/s, which equals 3 m/s as the correct answer.
72
What amino acids are the best phosphorylation site in Eukaryotes?
The amino acids that are the best for phosphorylation in Eukaryotes are: Tyrosine, Serine, Threonine, and Histidine.
73
If someone was using a microscope that had a focal length of 4mm with the object producing an image 5mm behind the lens, what is the samples distance from the object?
This seems difficult but take heart! Use the standard equation 1/f = 1/o + 1/i . We are trying to find O. Plug in our values and we get 1/o = 1/4 - 1/5 --> 1/o = 1/20 --> o=20mm .
74
When is entropy maximized in an isolated system?
Entropy is maximized when the system is both at equilibrium and is completing no work.
75
Under what conditions do gases perform most ideally?
Gases perform most ideally when there is a high temperature but a very low pressure.
76
What is the electron configuration for Fe3+?
Well, Fe has 8 more electrons than Ar (4s^2 3d^6), but they want to know about Fe3+, which has 3 less electrons. Remember, when removing electrons, begin with the highest quantum orbital (so, begin at 4s first). Our answer is 3d^5 for electron configuration.
77
What is the equation for Charles' Law?
The equation for Charles' Law is: T1/V1=T2/V2
78
In a chromotography stationary phase, what is going to be the primary factor determining migration of individual components?
Hydrogen bonds are what's most important in the stationary phase of chromotography
79
What does gas chromatography measure?
It finds the peaks of molecular compounds. Similar to SDS-page, it has the substance(s) move through a gel and the smallest ones will move the furthest while the largest ones will move the least. That is usually what it's meausring, molecular weight.
80
How do you know if a chiral center is R or S?
Draw the chiral center out! Label, from largest to smallest, each group attatched to the chiral carbon, then find out if it goes clockwise or counter clockwise. (Also, Sn2 will cause stereo-inversion)!
81
What's the difference between intermolecular bonding and intramolecular bonding?
INTRAmolecular forces is what holds a molecule together within it's own compound. INTERmolecular forces are what hold a group of molecules together.
82
What is Beta minus decay?
Beta minus decay is when an atom converts a neutron into a proton and ejects an electron from its' nucleus.
83
What is Beta plus decay?
Beta plus decay is when an atom turns a proton into a neutron and creates a positron and a neutrino
84
How would you find the reduction potential of a chemical equation?
First, split the equation into two half reactions. Then, use the equation E=Ecathode - Eanode. The cathode is always the one with the larger reduction potential (more positive E because it wants to be reduced).
85
What are the functions of the anode and cathode?
The anode will always Oxidize and the cathode will always Reduce
86
How would you find the magnitude between an electric field? (3 cm and 5 V)
Using the equation: E= q/d
| 5V / 0.03m = ~160 N/C (or V/m)
87
What equation would you use to find frequency if you were given lambda and the speed of light?
f=c/λ (frequency)=(speed of light) / (lambda)
88
If given a frequency (100Hz), how would you find the period of its harmonic?
Period is equal to one over frequency. T=1/f. If the first harmonic is 100Hz then the second is 200Hz and so on.
89
When a power is raised to another power, what do you do?
A power that is raised to another power is going to multiply; dividing powers subtracts, and multiplying adds powers together.
90
If you through a speaker up into the air, it emits a frequency of 170Hz the whole time, what is going to be the magnitude of the detected sound frequency shift during the flight?
Well, going upwards it will be negative, stop at zero when the projectile stops, then become positive as it falls back to the ground. Think Doppler effect.
91
What is a Bronsted-Lowry Acid/Base?
Refer to molecules that can accept or donate protons. Acids donate and bases accept
92
What is a Lewis Acid/Base?
A Lewis acid is a molecule that would accept a pair of electrons while the base is a molecule that would donate a pair of electrons.
93
What is an Arrhenius Acid/Base?
Arrhenius acids release protons and bases release hydroxide ions. Usually too narrow of a definition.
94
What is Gabriel Synthesis and how is it used?
Used to make primary amines or α-amino acids. Uses a nucleophil, Sn2 reaction to combine a compound with a nitrogen to create one of those two compounds.
95
Between R/S and L/D, what are amino acids generally made up of?
Cysteine is the only one that has an R, but all amino acids are in the S configuration and the L configuration. The D configuration can not be incorporated into proteins.
96
What type of molecules are characterized through UV Spec?
Anything that has a conjugated system of electrons--like a phenyl group--will show up in UV Spec and florescent experiments.
97
What would you use High-performance liquid Chromatography for?
Optimal for small sample sizes, high pressure mobile phase (using polar stationary phase), and separating compounds based on polarity.
98
What would you use thin-layer chromatography for?
Is NOT done under pressure. Needs a small sample, has a mobile phase, and uses UV Spec.
99
What would you use Gas chromatography for?
Needs small sample size but separates compounds based on boiling point (so, larger compounds leave last). Compound is vaporized (but not degraded or combusted). Mobile phase is gas not liquid and involves a stationary phase.
100
Which compound will have a stronger conjugate base, an acid with a high pKa (like 50) or something with a low pKa (like 2)?
The acid with a high pKa will have a stronger conjugate base. This also matchs the fact that increasing electronegativity also means a decreasing necleophilicity and vice versa.
101
How would you find out how many valence electrons nitrogen had?
Valence electrons are assorted in the same way down each period. So, group 1 has one, group 2 has two, etc. all going down the period. Nitrogen is in the 5th group so it has five valence electrons.
102
What's the difference between electrolytic and galvanic cells?
Galvanic cells convert chemical energy into electrical energy. Electrolytic cells turn electrical energy into chemical energy.
103
What is the Hell-Volhard-Zelinsky halogenation?
This is when we halogenate an alpha carbon (across a double-bond) and create a carboxylic acid from a ketone using PBr3 and Br2. You'll end with an alpha halogenate carbon and most likely HBr or something similar.
104
What are tosylates used for in organic reactions?
Tosylates are used as protected groups--usually for alcohols--which protects them from getting oxidized. Diols form an ester and work in the same way but for primary alcohols.
105
What enables keto-enol tautomerization?
Acidic anhydrides. Switches between the keto group and an alcohol with a double bond attatched to the alpha carbon.
106
What's the difference between an ester and an ether?
An ester is a carb acid but instead of the OH it's an OR group attached, whereas an ether is a ROR bond formation.
107
How does a charged particle act in an electric field?
A charged particle accelerates through an electric field.
108
How does a magnitic force effect a moving charge?
It would act on the moving charge perpendicular to both the velocity of the charge and the direction of the magnetic field.
109
What is the First Law of Thermodynamics?
Energy cannot be created or destroyed, only transformed. Energy is conserved.
110
What is the Second Law of Thermodynamics?
Entropy of the universe is always increasing.
111
Which side of the periodic table has elements that will readily conduct electricity?
The general consensus is that electrical conductivity increases as you go down and to the left. Use this to compare qualitatively.
112
What protein structures (primary through quaternary) are broken up during protein desaturation?
Secondary, tertiary, and quaternary structures are all disrupted.
113
What is the equation for the Force of gravity?
F=GMm/r^2 Force = (gravitational constant)*(mass of one object)*(mass of second object) / (radius squared)
114
What is the Third Law of Thermodynamics?
As an example, a book sitting on a table will have an equal but opposite force juxtaposed to the force it exerts on the table.
115
What is the Aufbau Principle?
The Aufbau principle states that the lowest energy electron orbitals need to be filled first. So, 2s needs to be filled before electrons can go into the P orbital.
116
What are the equations to find cetripetal force and acceleration?
To find centripetal force, we use: F=(mass)*(Velocity)^2 / (radius) and to find acceleration we use: (acceleration) = (velocity)^2 / (radius)
117
How would you find the force exerted by a magnetic field?
The equation is F=q*v*B . Force = (charge)*(velocity)*(Magnetic field). You need all three of these to envoke a force about a particle.
118
If a wire was positioned so that the magnetic field was pointing out of the page--so a clockwise current--but the magnetic field was doubled, what would happen to the current?
According to Lenz's Law, the current would change in proportion to the change in magnetic field, to counter balance the effects, and reverse it's direction and become counterclockwise.
119
What is the azimuthal quantum number?
Tells us in which particular shell the electron is found in and describes the shape of the orbital.
120
What is the principle quantum number?
Talking about the electrons shell and energy level. Can be found with each elements row in the periodic table.
121
What is the magnetic quantum number?
Narrows doen the electrons particular location within an orbital subshell.
122
Are perceived loudness and intensity of sound correlated?
Yes, there is a correlation! Intensity increases by powers of 10x (10,100,1000, etc.), while perceived loudness increases linearly with intensity by doubling (1x, 2x, 4x, etc.)
123
How does sound velocity and intensity change when traveling from air to a medium of greater density?
Sound waves increase in velocity when traveling in mediums of higher densities (liquids or solids). Intensity decreases as it travels into mediums with higher density.
124
How would you find the resonant frequency of a pipe with one end open and the other closed?
The equation L=λ/2 (Length) = (Lambda) / 2 can be used to find the length or the frequency.
125
What equation would you use to find the resistance of a resistor?
The equation is (Resistance) = (ρ [resistivity]) * (Length) / (Area)
126
What does the enclosed area of a pressure x volume graph represent?
The area is equivalent to the work done by the system.
127
What equation would you use to find the difference in force of two pistons with different areas?
Well, because P1=P2, we can use the equation F1/A1 = F2/A2 and solve for whatever our missing variable is.
128
What is the equation for fluid continuity?
Q1=Q2 or A1V1=A2V2 and this allows you to find a change in area or velocity.
129
What is the equation used to express change of energy, heat, and work done by a system?
The equation is: ΔU=Q-W [Delta U is change in energy] = [Q is change in heat of the system] - [W is change in Work of system]
130
Define conduction, radiation, and convection.
Conduction is just simple heat transfer from one object to another. Convection is heat transfer through fluid movement. and radiation is heat transfer but does not require direct contact--like conduction.
131
What is the equation for thermal expansion?
Well, there are two equations; one is for fluid and the other length of an object. ΔL=αΔT and for volume, Delta L is just replaced with Delta V.
132
What is an adiabatic system?
A system in which no heat or matter is transfered between system and surroundings.
133
What is an isothermic system?
A system in which the temperature is held constant.
134
What is an isochoric system?
A system where the volume is held constant.
135
What is an Isobaric system?
A system where the pressure is held constant.
136
How would you find the theoretical yield of a reaction?
Find out how many moles are in the product of the reaction, then multiply it by the compounds molecular weight.
137
Can the Doppler Effect be applied in space? Can you use sound waves?
The Doppler Effect can also be applied with sound waves. It can be used in space, but not with sound waves! Sound waves are longitudinal, they cannot be used in space, specifically. So, light waves are transverse waves and can be used in space.
138
What is the name of the technique to separate chiral compounds and how does it work?
It's called Chiral Resolution. It works based off the principle that chrial molecules are almost identical, but they react differently to other chiral compounds. Using another chiral compound to recrystallize only one enantiomer, will cause it to become a salt, while the other is still in solution.
139
Under what conditions are gases most soluble/insoluble?
Gases are insoluble at hight temperatures and low pressures. Contrary to that, gases are soluble at low temperatures and high pressure. This also means that solublity increases with gas partial pressure.
140
What is ionization potential?
It is the energy required to remove an electron from its atom. The larger the atom (like Mg) the more difficult it is to ionize, while the smaller the atom (like K) the easier it is to react.
141
How would you find the pressure exerted on an object at any point submerged in fluid?
The equation P=ρ*g*h which is (Pressure) = (Density)*(Gravity)*(height)
142
How would you find the percentage of something submerged?
Density of object / Density of liquid x 100 = % submerged
143
What is the difference between diamagnetic and paramagnetic?
They are both in terms of electrons in shells (and whether there are pairs to match equal-opposite spins). Diamagnetic means that all positions are filled and there is one electron up and one down throughout the whole orbital. Paramagnetic means there is an imbalance. So, in the P orbital all of the electrons are spinning up.
144
What is a disproportionation reaction?
A disproportionation reaction is one that has an element that is both oxidized and reduced in the same reaction. Example, a reactant (MgO2) forms two products (Mg2+ and MgO) where the reactant was oxidized and reduced.
145
What is the minimum amount of information to find index of refraction?
n (index of refraction) = c (speed of light) / v (velocity in sample) n=c/v
146
If a given bacteria absorbs green light to use in the creation of energy, what type of light will allow the creation of that energy? 1) UV light 2) IR light 3) Orange light or 4) radio waves
Anything with a greater amount of energy than the green light--in this case, the UV light--will allow the bacteria to produce energy with light. Anything with less energy than green light will not work.
147
What is the equation for Coulomb's Law?
F=(k)*(q1)*(q2) / (r^2)
148
What are the three equations to find Power using either resistance, current, or voltage?
Here are the three equations:
1) P=IV (Power) = (Current)*(Voltage)
2) P=I^2R (Power)=(Current^2)*(Resistance)
3) P=V^2/R (Power)=(Voltage^2)/(Resistance)
149
What's the equation to find capacitance?
C=Q/V (Capacitance)=(Charge)/(Voltage)
150
What is and how do you find Lorentz Force?
Lorentz Force is just the total force exerted on a particle. It's a sum of both electric force (F=Eq) and magnetic force (F=qvBsin(θ).
151
How would you find Kcat if given an enzyme concentration of 5 μm and rate (nM/s) of 125?
Well, the equation is Kcat=Vmax/[E] and 125 (nM/s) is our Vmax and our [E] is 5μM. The answer is 2.5*10^-2 s-1
152
How would these molecules separate using column chromatography? 2-butanone, n-pentane, propanoic acid, and n-butanol.
Well, using chromatography, we know there is a stationary phase where polarity will be important. Since all of these molecules have similar weight, polarity will be what differentiates them. Least polar will elute first and most polar will elute last
153
What is a sigmoidal shape of a graph indicate?
The sigmoidal shape of a graph indicates cooperative process.
154
What is the Venturi Effect?
When pressure of a gas or fluid is decreased in a tube or pipe while the pressure outside is greater. This creates an effect that pushes outside gas or liquid inwards.
155
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Which property of a substance is best used to estimate its relative vapor pressure?
A.Melting point
B.Boiling point
C.Molecular weight
D.Dipole moment
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Boiling point gives the best option for finding a substances vapor pressure.
156
What are coordinate covalent and ionic bonds?
They're the same things as normal covalent or ionic bonds, however, they involve atoms that are metals.
157
Do diverging lenses have positive or negative focal lengths?
Diverging lenses have negative focal lengths, which means that their images will always be virtual and reduced.
158
What's the difference between reflection and refraction?
Reflection is when light does not pass into another medium but reflects back into its own medium. Refraction is when light travels into a different medium but takes a slightly different path.
159
How would you find the refractive index (n)?
To find the refractive index, we would use the equation: n=c/vmaterial
160
In what directions do light rays reflect off of convex and concave mirrors?
For concave mirrors, parallel light rays will reflect inwards--to the positive focal point and forming a real image in front of the mirror. For convex mirrors, parallel rays will reflect outwards and form a virtual image behind the mirror with a negative focal point.
161
What is the equation that is used to find magnification?
The equation is m=-i/o (image)/(object). Also, make note that magnification for concave mirrors will be negative, while magnification for convex mirrors is positive. This has to do with where the images appear.
162
What are the three cases for convex mirrors?
1) Object is at a greater distance than the focal length, which will produce a smaller, upside down, real image. 2) Object is at focal length. This will NOT produce an image. 3) Object is at a point less than focal length and will form a virutal image at 2f on the other side of the mirror/lens.
163
What is the equation to find the power of a lens and what are the units?
The equation to find the power of a lens is P=1/f and units will be in diopters (m^-1).
164
What is the equation to measure mechanical advantage of a system?
The equation to measure the mechanical advantage of a system is F1D1=F2D2
165
What is an equation to measure sound intensity?
A good equation would be I=P/A
| Intensity)=(Power)/(Area
166
What is the equation to find the period of a pendulum?
T=2π(Sqrt)(L/g)
167
What is the equation to find decibels of sounds from intensity?
The equation is dB=10log(I/Io)
168
What is the equation to find the period of a moving spring?
T=2π(Sqrt)(m/k)
169
What is the Heisenberg Uncertainty principle?
The Heisenberg Uncertainty Principle states that the more precisely we know the position of a particle, the less precisely we know the particles momentum, and vice versa.
170
What is the primary bond created in an aldol condensation reaction?
In an aldol condensation reaction, the main thing that is needed is either an aldehyde or ketone that can under Sn2, which will ultimately form an α-β bond with an alcohol connected to the β-carbon.
171
Another example of Thin layer Chromatography.
Sheet coated in polar silica gel. Molecules are spotted on the bottom of the sheet. Sheet is placed in a nonpolar liquid. Mobile phase travels up the plate using capillary action. Nonpolar molecules have the highest Rf value.
172
What's the difference between Native-Page and SDS-Page?
Native PAGE does NOT denature while SDS-PAGE DOES denature
173
What are the four fundemental forces?
The four fundemental forces are: Strong and Weak nuclear forces, electromagnetic forces, and gravitation.
174
What is work function?
Work function is the amount of energy it takes to eject an electron from a given metal
175
How would a converging lens or a diverging lens change the path of a beam of light?
A converging lens would focuse the light and decrease its focal point but a diverging lens would increase its focal point.
176
What's the equation that will measure pressure change with cardiac output?
P=Q*R [Q=A*v] and R=resistance
177
What is Bernoulli's equation?
P+1/2*ρ*v^2+ρ*g*h=P+1/2*ρ*v^2+ρ*g*h
178
What's a difference between electrolytic and galvanic cells?
Galvanic cells are always spontaneous, but electrolytic cells are always NON-spontaneous.
179
If temperature and volume stay the same, what happens to the pressure if a sample of gas loses half of its molecules (beginning at 90atm)?
PV=nRT Know what is proportional and inversely proportional to each other!
180
When extracting a solution from a mixture, how many successive extractions would we want to perform? Is one extraction better than four? Why or why not?
If given the opportunity, more extractions will always allow a greater amount of separating from solution. So, four is better than one.
181
What is Lenz's Law and how does it apply to circuits and current?
Lenz's Law-->a law stating that the direction of an induced current is always such as to oppose the change in the circuit or the magnetic field that produces it.
182
What is Faraday's Law?
Faraday's Law-->a law stating that when the magnetic flux linking a circuit changes, an electromotive force is induced in the circuit proportional to the rate of change of the flux linkage.
183
How could you find the entropy of a chemical reaction like this one: CH4 + Cl2- ----> CH3Cl + HCL ?
When the MCAT asks about the entropy of a specific chemical reaction, look at the amount of moles. If there are 3 moles of reactants, but 5 moles of products, we know that entropy was increased due to more disorder than previously seen. The entropy change in this example is zero.
184
What are the base SI units of measurements?
- Meters
- kilograms
- seconds
- amperes
- kelvin
- moles
185
How can we tell if photons can be perceived from the release of energy--the changing of principle quantum numbers?
Well, anything that ends with the principal quantum number at n=1 will be ultraviolet. Anything that ends at n=2 will be visible rays, and anything that ends at n=3 will be is infrared. Therefore, it's impossible to determine where the principal quantum numbers began, but we can tell where they ended.
186
If an organic molecule is stable, will it also be a good leaving group?
NO! If an organic molecule is highly stable then it would be a terrible leaving group, with the opposite being true as well.
187
What is 'Transesterification'?
Transesterification is converting one type of ester molecule into another using an alcohol molecule.
188
How do you find the kinetic energy of a fluid? What's the density of water?
The equation to find the kinetic energy for a fluid is KE=1/2*ρ*v^2 *(volume)
and the density of water is 1000 kg/m^3 or 1g/cm^3
189
How would one find the amount of time it takes for a battery or capacitor to reach a certain percentage of its charge?
This is called the Time Constant and is found by multiplying resistance by capacitance, so Time Constant=RC
190
Are alkoxide ions good leaving groups?
NO! Alkoxide ions are awful leaving groups and are highly unstable as an -OCH3 group.
191
How would one determine the specific rotation of an enantiomer if given the other enantiomers' specific rotation (+21)?
Remember, the specific rotation is just the opposite of the initial rotation given (-21). Use the equation,
enantiomeric excess = (observed optical rotation) * 100 / (Specific Rotation)
192
If an organic molecule has 30 diastereomers, how many chiral centers does it have?
To find the number of chiral centers, 2^n (in this case 5) will give the correct answer. The original two molecules don't count as the diastereomers, thus the answer being 30 and not 32.
193
What is a coordinate bond?
A coordinate bond involves an electron-poor metal ion and molecules that donate electrons. Coordinate bonds are those formed between each molecule and the metal ion. Also, more bonds can form than the number of electrons donated.
194
Are free electron pairs counted when determining hybridization?
Yes, they are! Lone pairs of electrons are counted in hybridization but not when finding geometric configurations.
195
If given a question with a positive E value, is the reaction favorable--even if it's small?
Yes, the reaction is still favorable and will contain more (+) ions at the cathode, with electrons flowing from anode to cathode.
196
What is the 'nuclear charge' of an atom?
The 'nuclear charge' is the number of protons, minus the number of shielding electrons between the atoms' protons and their electrons. So, Z=z-s and more protons (without more electrons) mean a higher nuclear charge.
197
Are reactions balanced on the MCAT? How would you find limiting reagents in a reaction?
No, do not expect reactions to be balanced on the MCAT. To find limiting reagents, balance reaction and compare the ratio moles:coefficients of reactants, and you're done!
198
On the periodic table, where are atoms that have the MOST ionization energy (readily able to give up an electron)?
It's the opposite of polarity in the sense that it is the bottom left of the table that has the highest ionization energy with the lowest ionization energy being at the top right.
199
What does the palm, pointer finger, and thumb represent in the right-hand rule?
The thumb is the flow of current, the palm is the magnetic field (electrical field), and the pointer finger is the electrical force.
200
How do you spot a decomposition reaction?
A trick to spot a decomposition reaction is to make sure that there is only one reactant (the thing that is decomposing).
201
How would you separate a racemic mixture of enantiomers?
First, begin with a resolving agent (another chiral compound). The resolving agent forms a covalent bond or ionic salt. This creates a diastereomer, which has different physical properties that allow the separation of a racemic mixture. Afterward, once the diastereomers are separated, we just remove the resolving agent.
202
What term would be used to classify two isomers that have the same connectivity, but rotate plane-polarized light at +40 and -25, respectively?
Well, enantiomers have to rotate light equal but opposite to each other (like +25 and -25), so these isomers must be diastereomers.
203
Would a change in mass to charge ratio affect the color absorption or reflection of a compound?
No, only the change in electron structure would affect whether a compound would absorb light at 450nm or 680nm.
204
What is the Reverse-phase HPLC?
That's where the stationary phase is non-polar (they will elute last) and the liquid phase is polar (will elute first). So this is the opposite of normal HPLC.
205
What is a state function?
A state function is used to describe the equilibrium state and relationship between several variables in a thermodynamic system. The variables are a system's temperature, pressure, and volume.
206
What is a Process Function (or path function)?
Process function describes the path a system took from one equilibrium state to another. So, a positive or negative change in heat is a process function because it told you how it changed from one equilibrium to another.
207
Just know what type of transport is involved in keeping the membrane potential of a neuron somewhat steady.
The types of transport involved are passive transport, active transport, and membrane permeability.
208
Is the integration of viral DNA into the host genome part of the lysogenic or lytic cycle?
It's part of the lysogenic cycle, not the lytic cycle. Lysogenic is the propagation of the cells with the viral DNA, whereas the lytic cycle is when the cell lyses and spreads the virions.
209
Out of a population of 10,000 individuals, 900 of them carry a recessive allele. Find all of the individuals that will be heterozygous for the allele.
First, q^2=0.09, which means q=0.03. Then use the equation q+p=1 to find p (p=0.7). Then use the equation 2qp to find the heterozygous allele frequency. Should be 0.42 or 42% frequency.
210
What does B3 / THF and NaBH3 do?
Well, BH3 / THF will selectively reduce carboxylic acids to an alcohol, and NaBH3 will reduce Ketones and aldehydes.
211
What is the best way to find the molarity of salt in the ocean if the density of water is 1.028kg/L and the NaCl concentration is 3.5%?
Well, first multiple the concentration (3.5%) by the density (1028g), which would get 36g NaCl. Then divide the amount in solution by the molar mass of NaCl (58g) and boom! The answer is 0.62 moles.
212
What is a requirement to reach the boiling point? Does the vapor pressure need to meet or exceed atmospheric pressure?
For something to boil, a liquid just needs to meet, not exceed, atmospheric pressure.
213
Would a fluorene molecule have a stabilizing or destabilizing effect on a carbocation?
Fluorene would greatly destabilize a carbocation because it's highly electronegative, giving the carbocation a more positive charge, which is not good. Electron donating groups are good for carbocation stability.
214
What is the equation to find the magnitude of a magnetic field?
The equation is B=μI / 2πr
215
If asked to find the volume a person displaces in water, how would you find that? (given the value of their weight in the air, 700N, and their weight in water 40N)
Use the equation F=ρ*V*g and solve for volume. Also, subtract 40N from 700N and use that for the force in the equation.
216
What will be a better nucleophile, a compound with a very high pKa or a very low pKa?
A compound with a high pKa will have a strong nucleophile because the conjugate base is strong since the acid is considered weak. (Weak acids have high pKas and strong acids have low or negative pKas).
217
How would you find the ppm for a saline solution of 0.9% NaCl?
Well, assuming that it's 0.9% out of a 100g solution of water, take 100 away from 10^6, leaving you 10^4, and multiply it times 0.9 = 9,000 ppm
218
How would you find the kinetic energy of a photoelectron?
To find the kinetic energy of a photoelectron, multiply h*f - Work function = Kinetic Energy of Photon.
219
What is the primary driving effect of tertiary structures?
I know you were thinking of hydrogen bonding, which is a part of it, but the hydrophobic effect is the primary driving effect.
220
How do you find volume flow rate?
To find volume flow rate, use the equation Q=Av (Side note: A=π*r^2
221
What's an equation that can be used to find the frequency of a photon?
An equation that can be used to find the frequency of a photon is E=h*f
222
Going up and downfield for NMR spec, where will shielded or deshielded protons be located?
Deshielded protons will be located DOWNfield (higher numbers) and shielded protons will be located UPfield (lower number).
223
How would you find the work or the energy from a stretched band or spring?
Use the equation W (or U) = 1/2 * k * x^2 to find the work or energy from a stretched spring or band.
224
If there are a pair of glasses with a negative focal length, what type of lens is used in the glasses?
Because it's a negative focal length, it's a diverging lens with a virtual, reduced image that is produced.
225
What is the difference between anion-chromatography and cation-chromatography?
Anion-chromatography will bind anions (not cations) and cation-chromatography is just the opposite.
226
If you have a process that makes two enantiomers, one at 60% and the other at 40%, what does that say about their stability?
It can be inferred that the stability of the compound that has a higher percentage is the more stable compound thermodynamically.
227
What are the units for each variable in the equation Q=V*C?
The units are Coulombs for Q, Volts for V, and Farads for Capacitance. Remember, finding the energy of any capacitor uses the equation 1/2(C)(V^2) with the answer being in joules.
228
If given velocity how would you find power?
Another way to find Power is by multiplying Velocity times Force.
229
What would be a better predictor of thermodynamic stability, the heat of combustion, or boiling point?
The heat of combustion is more related to thermodynamic stability.
230
What is the by-product of a peptide bond? How many AMUs is that?
The by-product of a peptide bond is H2O and it weighs 18 AMUs.
231
When asking about the chemical properties of a gas, is important to use the "ideal gas" standard?
No. When talking about the chemical properties of a gas, it is important to note that London dispersion forces and dipole-dipole interactions.
232
What is a 'mixed' inhibitor?
A mixed inhibitor is one that can bind to the catalytic site of the substrate before or after the target binds to the substrate, which would cause inhibition either way.
233
What's the range for a buffer in an experiment?
The buffer needs to be within +/- 1 pH unit away from the pKa
234
Is pH equal to H3O+ of a solution?
Yes, it is! If the pH of a solution is 6, then the H3O+ is -log[H3O+], which is 1 x 10^-6 or a pH of 6.
235
An unknown amount of a radioactive isotope with a half-life of 2.0 h was observed for 6.0 h. If the amount of the isotope remaining after 6.0 h was 24 g, what would the original amount have been?
2^3 = 8 (1/8) is the amount left. Multiply 8x24 and you get the answer as 192g
236
Suppose a capacitor in a portable defibrillator needs to store 400 J at 5000 V. Roughly to what height would a 5 kg stone need to be raised in order to have the same stored energy as the energy stored in the defibrillator’s capacitor?
You don't need to include the 5000V, it's a trick! Just set it up as 400J = (5kg)*(10m/s^2)*(h) and solve for h. Easy as that.
237
In a blood pressure reading, which one is the higher pressure?
The systolic is the higher pressure (first) and the diastolic is the lower one (second).
