MCAT Chem Phys Flashcards
What is the normality of a solution? How would you find the normality of a solution?
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.
What happens to the pH/pOH of water as the temperature first increases, then decreases?
As temperature rises, the pH of water increases (becoming more basic).
What is the equation that allows you to find the concentration (molarity, volume, or weight) of substance needed to neutralize a solution?
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.
What equation is used to measure the force exerted on an object in an electrical field?
F=Eq Know how to convert units correctly!!
What is the equation for Tension?
Equation for Tension is T=rFsin(θ)
What are the effecting factors in bond angles? Are they a set number with no give or can they fluctuate at all?
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.
If current in a circuit changes, does anything else change?
V=IR! When Current changes, resistance does not (it’s a constant) but Voltage would change.
What is the equation to measure work done by a parallel plate capacitor?
Equation to find work done by a parallel plate capacitor is: W=1/2CV^2
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 ?
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.
What are the SI units for Conductance?
Units for condeuctance or conductivity are C^2 * s /kg * m^2
How do dielectric materials affect a capacitor, its voltage, and its electric field?
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.
What equation is used to find the energy emitted by a photon?
The best equation to use to find the energy emitted by a photon is E=hc/λ
If you doubled the mass of a pendulum, how would that affect its final height and velocity?
Periodic motion can be described as KE=PE. Mass is independent of final height.
What is Huckel’s Rule and how do you use it?
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.
What are Geometric Isomers?
Geometric isomers–> Refers to Cis or Trans configuration (possibly E and Z).
What are sturctural isomers?
Structural Isomers–> Are the same structural formula but in a different conformation (i.e. butane vs sec-butane).
What are constitutional isomers?
Constitutioal Isomers—> The same amount of molecules but arragned in a completely different manor.
What are the differences between Amines, Enamines, and Imines?
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.
How can we relate kinetic energy to temperature?
This equation shows that temperature is porpotional to kinetic energy KE=3/2kT
What is the Cathodes functions–and does it difer–between galvanic and electrolytic cells?
The Cathode end of the cell is ALWAYS going to reduce no matter what type of cell that it is.
What is the equation for Poiseuille’s Law?
The equation for Poiseuille’s Law is: Q=(πPr^4)/(8ηL)
What method would you use to attempt to separate 2-methylundecanal and 2-methylundecanoic acid?
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.
If an object weighing 10kg is dropped from 20m, what is the maximum speed achieved?
First, use PE=mgh, then use KE=1/2mv^2 and solve for v. Answer is 20m/s
Using a mechanical force test, what’s the distance from the ankle joint to the force applied? (F=98N and τ=13N/m)
Use the equation for torque (τ=rFsin(θ)) to find the radius (solve for r, obviously) Answer=133mm
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
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
What is the angle of incidence equal to?
The angle of incidence is equal to the angle of reflection (not refraction)!
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.
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).
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)
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.
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).
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.
What is the equation to find frictional force?
Equation for Frictional Force: F=Mgsin(θ)
What is the equation for Buoyant Force?
F=ρVg (densityvolumegravity).
What is Reynold’s Equation?
Re=ρvd/μ
Density)(volume)(length) / (new
What is the Pauli exclusion principle?
Electron spin is opposite of each other
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.
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.
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.
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.
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)
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!
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.
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.
What is the minimum frequency for ultrasound?
Anything above human hearing. So, anything above 20kHz
Where are the enzymes located–inside of the cell–that help convert pyruvate into glucose?
In the cytosol and the mitochondria.
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].
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).
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
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.
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).
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
Which environment will have better solubility: a cold environment or a hot environment?
Cold environments have better solubility.
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).
What factors, if any, can alter Ksp?
The only factor that can alter Ksp is temperature. Changing the concentration will NOT alter Ksp!
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.
If a solution is titrated half way (at its’ equivalency point) what is the pH or pKa?
At half-equilvancey point, pH=pKa!
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.
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.
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.
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
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.
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.
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.
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.
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!
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!
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
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.
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.
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.
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 .
When is entropy maximized in an isolated system?
Entropy is maximized when the system is both at equilibrium and is completing no work.
Under what conditions do gases perform most ideally?
Gases perform most ideally when there is a high temperature but a very low pressure.
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.
What is the equation for Charles’ Law?
The equation for Charles’ Law is: T1/V1=T2/V2
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
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.
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)!
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.
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.
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
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).
What are the functions of the anode and cathode?
The anode will always Oxidize and the cathode will always Reduce
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)
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)
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.
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.
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.
What is a Bronsted-Lowry Acid/Base?
Refer to molecules that can accept or donate protons. Acids donate and bases accept
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.
What is an Arrhenius Acid/Base?
Arrhenius acids release protons and bases release hydroxide ions. Usually too narrow of a definition.
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.