Chem/Phys Flashcards
Use instantaneous or average velocity for PFGE?
Use average velocity for multiple changes. Instantanous will not help because it does not account for more than one trial.
Average speed and velocity in gel that only goes in one direction?
Average speed and volcity will be similar in gel that travels one direction.
What happens in PFGE when there are 2 bands for DNA?
They will separate more
What Ka to use when pOH 4.8?
Use Ka of 6.2*10^-10 because pH=9.2 so use Ka same as pH for a buffer
Electric field points where?
From (+) to (-). An axon is negative
Is sodium, potassium, or chloride ions smaller?
Sodium because smallest MW
Given 100 m/s, what is distance of electrodes?
Look in graph for milliseconds
What is needed to find resistance?
Need resistance per unit length and length
What will y intercepts be given multiple V max on lineweaver burk plot?
All intercepts will differ
Pressure inside buriet will be what when water inside is higher than outside?
Lower
Given density and volume, finding mass. Density kg/cm cubed?
Divide by 10^6
What is needed to solve using dopplers effect?
speed of sound, frequency of sound waves emitted and observed. Not speed of moving object.
How to determine which active site determines binding?
Whichever binding site has more competing
Given that hydrophobic and anionic are ligand, which amino acids bind?
L and R
How to solve for density of human body when some is in water?
W(air)/[W(air)-W(water)]
Determine charge with what groups?
Carboxylic acid and phosphates
Phosphate on which carbon on ribose?
3
Solve for frequence given h and E?
f=E/h
What would doppler help measure in body?
blood flow because measures differences in speed based on frequency
Given P and V, change P, what will new V be to keep the same ratio?
Use PV=PV
Gas will behave not ideal in what condition?
High pressure, low volume
Find total pressure given moles of each and pressure of 1?
Add all moles and solve by total moles.
Given standard reduction potentials (E), which is best oxidizing agent?
Flip signs to make them negative, the less negative one is better oxidizing agent.
Given standard reduction potentials (E), both negative, in electrolytic cell, which will reduce and oxidize?
More negative reduction potential will reduce because eletrolytic cell.
What changes/will not change as light goes from 1 media to another?
Velocity and wavelength will change. Frequency will not change.
Required for doppler effect?
One must be moving toward or away to detect shift.
Open pipe vs closed pipe harmonics?
Open= 1, 2, 3… Closed= 1, 3, 5…
Minimum velocity in spring?
zero
Percent above water given density= 491?
50.9% because 491/1000 is in water
Given acceleration, mass to charge ratio (do 1/x), find strength of electric field?
E= ma/q
Using strontium instead of potassium, electric field required would be?
Less than 2E but greater than E because +2 charge and also twice mass will almost cancel out
How will current travel?
Least resistance!
How to double capacitance?
use a radius of 2^(1/2)r
Work done in magnetic field?
Zero because work is done parallel, magnetic field perpendicular
Carbon configuration in amide hydrolysis?
sp3->sp2->sp3 (N attacks carbonyl)
Why does light more slowly in optical lens than through a vacuum?
light is absorbed and re-emitted by the atomic structure of the optically dense medium
What will electron do when released from cathode in eletric field?
Accelerate towards anode. Current will begin to flow
Increase frequency of a photon has what effect?
Increases speed of ejected electrons, does not effect number ejected
Increasing speed of charged particle will affect electric force how?
Will not affect electric force. E= qE
Given mass, charge, and electric field, how to find acceleration?
A= qE/m
How to change focal length?
Change radius is only way
Charge cannot accumulate indefinently on a capacitor because?
Two plates of capacitor accumulate charge of different sign. As you collect more, the other is harder to add because repulsion (hard to reach until equilibrium)
When capacitor discharges, how to keep same current?
Must reduce resistance because voltage decreases as capacitor discharges
What can store energy?
Batteries and capacitors
Pressure of fluid formula?
P= gravity * height * density
What is 0.707/0.5
700/500 equals 1.4 so answer 1.41
Going from lower to higher index of refraction?
Light should bend towards the normal (air to bead)
Effect on image when larger index of refraction is used?
Image will move (not smaller or larger)
How to solve for wavelength when given frequency, speed of light and diameter?
Solve wavelength= V/f and then Diameter / wavelength
Solve for pressure difference in fluid?
pressure= density * gravity * delta height. Do not do pgd = pdg
How much of ball is floating?
mg= pvg
Solve for artery blood flow when diameter cut in half?
speed doubles because stays constant
When using stronger magnet what happens?
F= qvB so voltage increases
How to make tone lower in violin?
Use heavier strings. Do not mess with wood
How block accelerates in pulley system?
Coefficient of KE is always smaller than coefficient of static friction. Constant force on mass produces linear acceleration (second newton law) not exponential
How to solve for coefficient of static friction?
frictional force/normal force
What will velocity be when released at 10 m vs 20 m?
20 m will have velocity increased by a factor of (2^1/2)
If cart moves without brake a stops, use what for force? (FV for power)
Use friction not brake force
Will graph be linear or exponential when braking for velocity vs time?
exponential decline
How to solve for thermodynamic stability of organic compound?
use heat of combustion, not boiling point
Where to label on a guanine?
Label on carbon because it can not hydrogen bond
Kb>Ka implies?
better base
Given mass of glucose is 72g/L, how many g in 2 L?
multiply times 2 so 140
What must occur to have reliable data for michaelis menten kinetics?
measure Vo in steady state, solution pH maintained at all substrate concentrations, concentration of enzyme less than substrate NOT allow reaction to reach equilibrium before measuring
What does hydroxamic acid look like? Given that it has acetyl and hydroxyamine nitrogen
Need RC=O and NHOH
What is reduced in rxn?
Look for it in passage picture
Aromatic amine or phenol has?
Full ring and OH or N on outside
What would be used for coordination of calcium?
Oxygen- need something with negative
Heme cofactor looks like?
Need a 5 member ring with nitrogen in it
Parabola with time on X and distance on Y?
d relates to t by d=t^2
What does not change with ultrasound wave as it goes through a person?
FREQUENCY
Given Av, and area and units, how to solve for sound?
Av/na
Amine+ester yeilds?
amide
Purpose of acid catalyst for esterfication?
Protonates carbonyl oxygen, making it more susecptible to nucleophilic attack by alcohol
Which forces are not conservative?
Friction, metabolic heat loss, rotation of front wheels
Sn2 result
inverts stereochem
9 L in 10 min?
900 mL/min
disulfide bonds are?
intermolecular covalent bonds
used for structure in peptide?
arginine and asparatate. not cysteine
net charge change R33Q D34N K112D, M134D, Y139C, I157M?
goes from +2 to -2
H3PO4- vs HPO4 2- dissociation?
HPO4 2- dissociates less because negative
enthalpy formula
reactants - products???
highest vibrational frequency?
C=O because stronger bond (larger H)
effect of resonance on heat of combustion
decreases it
how to trasnfer heat from colder to hotter place?
do work on the system to transfer heat non spontaneously
wax ester structure
no hydrophilic head. saturated has higher MP than unsaturated because stacking
volt is equal to?
energy per charge
lowering temperature causes?
exothermic reaction
combustion reaction is spontaneous or nah
spontaneous
heat of vaporization?
gas - liquid (endo)
if 80% efficient, produce 27 W?
no because problem said v= 9 and r =3 and P= V2/r
radius when flow is 0.2 and original is 3.2?
0.2/3.2 is 1/16 so 1/16=r^4 so 0.2 so 2-.2 = 1.8
greatest root-mean-square speed?
element with smallest MW because equation is v = root 3RT/M
why use helium in terms of periodic table trends?
has highest ionization energy. also has low electronegativity (like noble gases)
find PE given F and x?
First find k. then plug into PE= -1/2kx^2
where do proteins go in anode cathode?
SDS makes proteins negative charge. Goes to anode because anode has higher potential in electrolytic cell.
Boyle law? Charles law? Gay-Lussac? Avogadros?
B: PV C: V/T G-L: P/T A: V/n
Pressure O2 at top of everest, drops 67%? O2 pressure is 21%
760(1/3) = 25321%= 53
H2O, He, H2, or N2 deviate from ideal gas the most?
H2O because ideal gas behavior broken when molecular volume and/or intermolecular forces increase. H2O has H bonding
which will help alleviate altitude sickness? Due to less O2, so we breathe more but this can decrease CO2. This would shift equation left and cause alkalosis
inhaling oxygen from oxygen tank, acetazolamide, a diuretic that directs bicarb excretion, and breathing into paper bag. Consuming antiacid like NaHCO3 will NOT
The function -cos(t) is how many degrees out of phase with sin(t)?
-270
Perchloric acid is a superacid used in the production of rocket fuel. If two moles of perchloric acid are mixed with four liters of water, the normality of the resulting solution will be closest to:
Perchloric acid is HClO4. so 2 mol HClO4 / 4L = 0.5 M
molarity vs molality
molarity: mol/L molality: mol solute / Kg solvent
600 mL of 1.5 M benzene-1,4-dicarboxylic acid (C8H6O4), one of the primary reagents used in the manufacture of Kevlar, is diluted with 2.4 L of water. What is the final molarity of the solution?
use M1V1 = M2V2, keeping in mind that V2 must include the 2.4 L of water as well as the original 0.6 L of solute. M2 = (M1V1) / V2 = (0.6 L × 1.5 M) / 3 L = 0.30 M.
17.5 g of ammonium hydroxide (NH4OH) is mixed with 250 mL of an unknown solvent with a density of 1.5 g/mL. The molarity of this ammonium hydroxide solution is:
Molarity is measured in moles of solute per liter of solution, so we first must find the moles of ammonium hydroxide present. 17.5 g NH4OH × (1 mol NH4OH / 35 g) = 0.5 mol NH4OH. Now, we can easily find the solution’s molarity by taking 0.5 mol NH4OH / 0.25 L solution, or 2.0 M.
A well-sealed flask found in a laboratory is said to contain a 1.5 M solution of an unidentified compound. The solution is measured to be 3.5 L and to have a density of 0.5 g/mL. What is the molar mass of this compound?
As the flask is well-sealed, we can assume that the molarity on the label is correct; otherwise, this would be an impossible question to answer. (1.5 mol compound / 1000 mL) × (1 ml / 0.5 g) = 0.003 mol/g, or 333 g/mol.
treat aldehyde with LAH?
forms alcohol
Based on the information given in the passage, what is ΔS° for Reaction 5 at 25°C? only given S and temp
find delta G by (products - reactants) and then plug into G=H-TS
researcher studying the equilibrium described by Reaction 2 needs to produce more calcium oxide. Which of the following is most likely to produce this result?
Increase temp because told it is endothermic so heat is reactant and calcium oxide is product
Find Ka equation given that it is dissociation?
H+ A- / HA
find pI given graph?
shows flat part at high pH so use the upper two pKa to find pI
While playing, a 40-kg child is accidentally pushed directly forward off a ledge, causing him to fall and hit the ground at a 60° angle. If the child has 720 J of kinetic energy at the instant before impact, at what velocity was he pushed? Assume negligible air resistance.
1/2 m v^2 * cos 60 = 6 * 1/2 = 3
According to the passage, which of the following individuals is LEAST likely to experience a fracture, assuming that all have the same mass and fall onto hard-packed earth from a height of 2 m?
A person with a relatively large bone cross-section who hits the earth at an 80° angle to the ground. (10 degrees from normal)
How much does the rate of effusion of dichloromethane at 200 K change when the temperature is changed to 800 K? Assume all other conditions are identical.
Rate of effusion depends on root-mean-square speed, which is calculated using the formula vrms = √(3RT)/M. so square root 800/200 = 2 so increase by 100%
Ribonuclease? deoxyribonuclease?
cleave RNA, cleave DNA
5 x 105 J of energy is given to each 5-kg sample of the following solid substances at their respective melting points. Which of the following samples will have the highest percentage of melted substance?
latent heat of fusion is amoutn of heat to melt. lower means melts more
Tissue engineers have been developing a synthetic mineral apatite to use in prosthetics that is comprised of repeating molybdenum hexacarbonyl [Mo(CO)6] subunits. This bonding is likely to involve which of the following orbitals?
d2sp3 not sp3d2. In sp3d2 hybridization, all of the orbitals have the same principal quantum number. In d2sp3 hybridization, the principal quantum number of the d orbitals is one less than the principal quantum numbers of the s and p orbitals, as is the case here. We see d2sp3 hybridization in the transition metals and sp3d2 hybridization in the nonmetals.
An experimenter proposed employing a material with an index of refraction strongly dependent upon the wavelength of transmitted light for use in an objective lens. How would the use of such a material impact the performance of a microscope?
Images formed by the eyepiece from transmitted light containing multiple wavelengths will be unfocused.
Refractive myopia is corrected by the use of a diverging lens of appropriate optical power. When compared to a healthy eye, a myopic, but otherwise normal, eye’s near point is most likely:
smaller than a healthy eye
In order for the image produced by the eyepiece to be erect, where must the image focused by the objective lens fall?
At a distance from the eyepiece smaller than the eyepiece’s focal length. (Must be smaller than focal length)
The compound 2,3-dihydroxybutanedioic acid (tartaric acid) has how many stereoisomers?
3 because one is meso
After reacting 1-phenylethylamine with (R,R)-(+)-tartaric acid, which of the following best explains what causes the two ionic forms to have different physical properties?
diastereomers
In an isolated system, entropy is maximized when:
I. the system is at equilibrium.
II. the system is far from equilibrium.
III. the system is unable to perform work.
I and III. Recall that at equilibrium, ∆G = 0. With no free energy change, the system is unable to perform work (eliminate answer choices A and B). At equilibrium, there are no energy gradients within the isolated system, so energy is maximally dispersed, resulting in maximal entropy (eliminate choice D).
II: A system that is far from equilibrium contains large energy gradients which are able to perform work. The formation of large energy gradients requires localization or concentration of energy, which results in decreased entropy.
gas behaves ideally in what conditions?
high temperature, low pressure (546 K and 50 Pa) 1 atm = 101,500 Pa
An object floats in water with 4/5 of its volume submerged. If the object is then placed in a type of oil with a density half that of water, which of the following is true about the object placed in the oil?
Vfluid / Vobj = ρ obj / ρ fluid , where V fluid is the volume of displaced fluid (here, it’s water).
V fluid / V obj = 4/5, so ρ obj / ρwater = 4/5.
The question tells us that ρwater = 2ρoil. This means that 4/5 = ρobj / 2ρoil .
Therefore, ρobj / ρoil = 8/5. Since the ratio of densities is larger than 1, we know that the object is more dense than oil, and it will sink to the bottom.
Which of the following best represents a flaw with PAD when attempting to measure the volume flow rate of blood through a cross-sectional segment of a cerebral blood vessel?
unable to determine frequency of absorbers moving perpendicular
Sound waves reaching the ultrasonic transducer propagate through brain tissue via which of the following mechanisms?
collision of adjacent particles within the tissue. NOT Vibration of particles perpendicular to the direction of wave motion in the tissue because this is for light
What best explains the discrepancy between these results and the IR results in Figure 1?
The infrared spectra of most alcohols are typically recorded as neat liquid films or Nujol mulls. NOT in gas
IR given in gas phase not liquid, sharp peak at 3700?
OH (not broad like it is supposed to be in liquid) C-H are at 2900
If a high school athlete throws an average pitch of 30 m/s from the mound completely horizontally, and it leaves his arms 2 meters above the ground, how high will the ball be when it crosses home plate, which is 18 m away from the mound?
Δy = ½ (-10 m/s2)(t2)
Unfortunately, we do not know the time, but we can solve fairly easily using the formula Δx = vxt. (This simple formula works because the ball does not experience acceleration in the horizontal direction.) We must rearrange to get t = Δx/v x, or t = (18 m) / (30 m/s) = 3/5 s = 0.6 seconds.
Plugging into the first equation yields Δy = ½ (-10)(0.6)2 = -1.8 m. Thus, the ball will end up exactly 2 - 1.8 = 0.2 m above the ground.
Absorption of radiation corresponding to what portion of the electromagnetic spectrum is most likely to excite Aequorea fluorophore, a green fluorescent protein used in biological experiments?
ultraviolet (associated with green light)
It was attempted to use dipropyl ether as a solvent and diethyl phthalate as a solute. Dipropyl ether is nonpolar. What results might be expected, assuming that the diethyl phthalate dissolved as intended?
induced dipole interactions becasue diether phthalate is polar and induce dipole on dipropyl ether
the blood-brain barrier prevents molecules from easily entering the central nervous system unless they are able to pass through the lipophilic plasma membranes of the cells making up the barrier. Which of the following is most likely to be true?
Diethyl phthalate is more likely to cross the blood-brain barrier than phthalic acid because it lacks hydrogen-bonding hydroxyl groups. Non polar groups like steriod hormones can pass
Which of the following must be true for a biochemical reaction at equilibrium?
delta G = 0. NOT ΔGº’ = 0
C. Keq = 0
D. Q = 0
Approximately how many grams of zinc sulfate are in 50 mL of the standard solutions used in the galvanic cells?
50 mL x (1 L/103 mL) x 1.0 mol/L x 161 g/mol =
5.0 x 101 x 10-3 x 1.6 x 102 =
5 x 1.6 = 8 g
Copper (II) ions in aqueous solutions cannot be directly extracted into organic solvents without an extractant because the ions:
have greater solubility in water than organic solvents unless complexed with extractant.
The hydrotrope sodium benzoate is formed by the reaction of NaOH and benzoic acid. In aqueous solution, this hydrotrope is:
weakly basic. The salt of a weak acid will be a weak base
hyperbolic shape acceleration?
decrease acceleration
double frequency of wavelength 532?
wavelengt now 266
What is the kinetic energy of a photoelectron produced in the energy meter of the PAC device when the frequency of an incident photon that is NOT absorbed in the solution is f = 5.0 × 1015 Hz? (Note: Use h = 4.1 × 10–15 eV•s.)
kinetic energy of a photoelectron is equal to hf – 3.4 eV = 20.5 eV – 3.4 eV = 17.1 eV.
name of lipid that is phosphatidyl choline?
phosphatide
Why did the liposomes fluoresce during size-exclusion chromatography?
Liposomes can be difficult to detect since they do not absorb visible light and many molecules absorb UV light. The experimental design allowed fluorescent dye to be trapped inside during liposome formation, which allowed their detection by fluorescence spectroscopy.
What is the Km of Compound 1 with respect to lactase?
1/S so 1/.05= 20
What method did the students use to calculate Vmax?
Vmax was determined as the inverse of the y-intercept of the graph shown in Figure 1.
What is the structure of the cytosine base after catalysis by Dnmt3a?
said methylated at carbon 5. “Carbon 1” is the NH
Dnmt3a was purified using which type of column chromatography?
use of histine tagging and a nickel column is a form of affinity chromatography.
at pH 7.3, bond order of shortest bond in glycine?
1.5 (resonance)
