Chem-Phys

Question 1

Do cell membranes made with phosphatidyl-choline/-ethanolamine require a counter ion? why or why not?

Answer 1

No. they are charge balanced b/c (+) charge of choline/ethanolamine group offsets (-) charge of phosphate grp

Question 2

“Difference between isomers…

1. structural
2. geometrical
3. conformational
4. optical”

Answer 2

1. structural: different connectivity
2. geometrical: cis vs. trans.
3. conformational: interchangable structures by rotation abount a bond
4. optical: enantiomers—»same connectivity, different spatial orientation about chiral center”

Question 3

treatment of Oleic acid with D2/Pd would yield a compound with how many chiral centers?

Answer 3

Question 4

what factors increase membrane rigidity?

Answer 4

1) inc. degree of saturation
2) inc. # of carbons

Question 5

which of the following alcohols are oxidized by Na2Cr2O7?

• phenols
• methyl/1º alcohols
• 2º alcohols
• 3º alcohols

Answer 5

methyl, primary, & secondary alcohols

Question 6

How can you quickly identify whether a change in oxidation state is an oxidation or reduction? (i.e. S–S —» S–C)

Answer 6

If an atom is bound to a more electronegative atom —» oxidation

If an atom is bound to a less electronegative atom —» Reduction

Question 7

what is the difference in structure of an enamine vs. imine

Answer 7

Question 8

What forms when an aldehyde is treated with a grinard reagent?

Answer 8

a 2º alcohol is formed

Question 9

Pinacol Rearrangement

Answer 9

Pinacol Rearrangement: converts a vicinal diol (OH groups on neighboring carbons) into a ketone via an alkyl shift.

Question 10

of the 4 types of compounds, which are/are not reduced by NaBH4?

• phenol
• 3º alc
• ketone
• ester

Answer 10

• phenol —» no
• 3º alc —» no
• ketone —» yes
• ester —» no

Question 11

Answer 11

Question 12

if a food molecule (i.e. carb, fat, protein, etc.) isn’t metabolized by the digestive system, how many dietary calories are contributed to the consumer?

Answer 12

0 Cal are contributed to the consumer b/c anything that isn’t metabolized cannot provide any energy & ∴ no calories.

Question 13

why is a solution of NaNO2(aq) basic?v

Answer 13

NO2- reacts w/H2O to form OH- ions, thereby inc. pH of solution

Question 14

if there are 60 million nuclei of a radioactive atom (half-life of 430 years), how many years would it take before there are 3.75E^6 nuclei remaining?

Answer 14

• 1 half-life = [(# nuclei) / 2]
• (3.75E6)/(60E^6) = 1/16 = [4 half-lifes]
• 4(430) = 1720

Question 15

What are 2 different units for electric field?

Answer 15

1. Newton/Coulomb (N/C)
2. Volt/Meter (V/m)

– 1(V) = 1 (J/C)

Question 16

what type of interference occurs when two waves are out of phase by 180º?

Answer 16

Destructive Interference: occurs when two waves that meet when they are half a wave difference out of phase (180º)

Question 17

how does the period of a waveform change as you move up through the 1st, 2nd, & 3rd harmonic? what about wavelength? frequency?

Answer 17

• the period (T) DEC. as you move up a harmonic level (i.e. 1st—»2nd)
• the wavelength DEC. as harmonic level increases
• if 1st harmonic = [100 Hz], 2nd = [200 Hz], 3rd = [300 Hz], etc.

Question 18

what is the only effect that the photon frequency has on ejected electrons?

Answer 18

• photon frequency only affects the ejected e-‘s KE —» ∴ inc. in frequency = inc. in KE = inc. speed of ejected e-
• photon energy = cathode work function + KEelectron

Question 19

if someone drinks an extremely hypertonic/hypersaline solution, why would this person be at risk of death?

Answer 19

ingested salt would be absorbed into the blood, creating a hypertonic environment outside the cells of the body—»causes water to flow out of the cell causing it to shrivel

Question 20

How does adding salt to water affect it’s boiling point & vapor pressure?

Answer 20

1) adding salt inc. BP of water
2) adding salt dec. VP of water—»∴ as solute inc., the rate of water molecules breaking the liquid surface dec.

•BP—»the temperature at which VP of solution = VP of the atmosphere

Question 21

what allows H2O to exhibit the unique property where it’s solid state (ice) is less dense then the liquid (water)

Answer 21

• the bent structure of H20 (bond angle ~104.45º) & the high degree of hydrogen bonding yields a hexagonal crystalline structure w/alot of space between molecules

Question 22

1) Β- Decay
2) What is the product of I-131 B- decay?

Answer 22

1) conversion of neutron to proton & loss of 1e-

• element undergoing B-decay will convert to an element w/1 additional H+

2) Xe-131

Question 23

What are the 4 main types of radioactive decay?

Answer 23

1) α-Decay: emission of alpha particle (2 protons & 2 neutrons [2+])
2) B- / B+ Decay:

• B- = neutron converted to H+ and B- particle (e-) ejected
• B+ = H+ converted to neutron and B+ particle (positron) emitted

3) Gamma Decay: emission of gamma ray (high energy photon) and release of ionizing radiation
4) Electron Capture: nucleus “grabs” an e- —» converts H+ to a neutron

Question 24

if a child and an adult are exposed to the same contamination levels of I-131, would the child, compared with the adult, recieve a higher, lower, or equal relative dose?

Answer 24

• B/c children weigh less, the same quantity of external I-131 results in a higher concentration of the isotope in the body
• higher concentration = inc. likelyhood of DNA damage & cancer

Question 25

If 2-methylundecanal and 2-methylundecanoic acid are separated by distillation, which compound would be found in the collecting flask and which would be found in the initial boiling flask?

Answer 25

• distillation separates compounds based on difference in BP w/the lower BP molecule evaporating off first ∴ …

-Collection Flask = 2-methylundecanal

-Boiling Flask = 2-methylundecanoic acid

Question 26

What is the formula for the velocity of an object dropped from a given hieght (h)?

Answer 26

v = √2gh

Question 27

what is one way to quickly identify whether or not a carbon is a stereogenic center?

Answer 27

for a carbon to be a tetrahedral stereocenter, it must be bonded to 4 different substituents

Question 28

if a runner undergoes a turning acceleration to make a turn, how would you determine the magnitude of force experienced by the foot due to the ground?

Answer 28

• Fnet = √(Fnormal^2) + (Fturn^2)
• Fturn is ⊥ to Fnormal ∴ resultant = Fnet

Question 29

For a polyprotic acid, what are the requirements for a H+ to produce a visible inflection point?

Answer 29

• a H+ will only produce a visible inflection point if the H is relatively strong (low pKa)
• pka1 vs. pka2 must differ by at least a factor of 10^4

Question 30

1) what is the equation for the moles of acid of a monoprotic acid at the equivalence point?
2) If you are given the titration curve for captopril w/NaOH & the concentration of NaOH, how would you determine the mols of captopril in the original analyte solution

Answer 30

1) Mb x Vb = Ma x Va = moles acid
2) determine volume of NaOH at the inflection pt of the titration curve (middle of steep portions) and use the concentration to determine the number of moles of NaOH at the inflection point. Mol OH = Mol Captopril

Question 31

Newton’s Laws

Answer 31

1) Newton’s 1st Law: states thaat within a reference frame, an object remains at rest or at a constant velocity unless an external force acts upon it

• Fnet = 0 ; at equillibrium

2) Newton’s 2nd Law: Fnet = ma

3) Newton’s 3rd Law: when body A exerts a force on body B, body B exerts and equal and opposite force on body A

• Fa on b = -Fb on a

Question 32

How would you determine whether a data point with error bars is significant?

Answer 32

if error bars overlap between data points that are being compared, then the difference between those pts. is NOT SIGNIFICANT

Question 33

Within the ETC, are e- passed from species w/less positive to more positive reduction potential or vice versa?

Answer 33

• within the ETC, e- are passed from species w/less positive reduction potential to those w/more positive reduction potential
• O2 = final e- acceptor—»∴ possess most postive standard reduction potential

Question 34

standard reduction potential (Eº)

Answer 34

• tendency for a species to spontaneously become reduced
• defined relative to standard hydrogen electrode (2H+(aq) + 2e-(aq) —» H2(g))
• Units: volts
• (+) Eº —» stubstance ‘wants’ to be reduced
• (–) Eº —» substance not prone to reduction
• Eº Cell = Eºcathode + Eºanode [total standard potential generated by a galvanic cell]

Question 35

For a redox reaction, where are specieces reduced vs. oxidized?

Answer 35

1) Cathode (+) —» electrode where reduction occurs

2) Anode (–) —» electrode where oxidation occurs

Question 36

If you’re given the energy released by NADH thru the ETC (at 50% efficiency), how would you determine if energy produced by the rxn would be sufficient for the generation of 3 ATP molecules.

• energy released by NADH = -52.5 kcal/mol

Answer 36

• at 50% efficiency, only 26 kcal/mol could be used to produce ATP
• 3 ATP —» 1 ATP (7.3 kcal/mol) x 3 = 22 kcal/mol ∴ enough energy would be produced to generate 3 ATP from the e-pair from NADH

Question 37

Refractive index

Answer 37

• refractive index (n) helps reference how a waves speed will change within different mediums releative to it’s speed in a vaccum
• n = c/v

(v=velocity through medium, c=speed of light)

Question 38

Snell’s Law

Answer 38

• relates how the propagation speed of a wave changes from one medium to another —» relates the refractive index to how much the light bends upon entering the new mediuim
• n1sin(Ø1) = n2sin(Ø2)

Question 39

What is the hybridization of XeF4?

Answer 39

sp3d2

Question 40

What is the relationship between ∆Hf & the rxn rate?

Answer 40

• ∆Hf (heat of formation) = energy required for the formation of a molecule
• lower ∆Hf = quicker rxn rate

Question 41

what is relative stabilization energy (RSE)? how does RSE relate to the stabilizing effects of a molecule?

Answer 41

RSE —» (–) RSE = greater stabilization

Question 42

Hess’ Law

Answer 42

∆Hrxn = ∑∆Hf [products] - ∑∆Hf [reactants]

Question 43

What is the difference between enthalpy vs. entropy?

Answer 43

Enthalpy = heat energy in a system

Entropy = energy in a closed system that is unavailable to do work

Question 44

What is the relationship between electronegativity (w/respect to the substituent) and its stabilizing effects on a carbocatrion?

Answer 44

• carbocations are unstable b/c of high concentration of positive charge ∴ substituents that contribute e- density to the carbocation will charge balance the carbocation
• EWGs pull e- densityt away from carbocation, further decreasing its stability

Question 45

1) Gibbs Free Energy Equation
2) is it possible for an endothermic rxn to proceed spontaneously?

Answer 45

1) ∆G = ∆H - T∆S
2) YES. If ∆S is a large, (+) number, then it could make the overall ∆G of a rxn (–)

Question 46

spontaneity relationship table for ∆H, ∆S, and

Answer 46

Question 47

What does the power of a study refer to?

Answer 47

Power: refers to the ability of a study design to detect a real statistically significant effect, and it is primarily affected by the size of the study and the size of the effect - larger sample = more power

Question 48

Capacitor

Answer 48

• Capacitance (C): C = εA/d

• A: area of plates
• d: distance btwn plates

• Medical applications of capacitors (i.e. defibrillators to store charge and electrical PE)

Question 49

? atm = ? mmHg = ? Pa

Answer 49

1 atm = 760 mmHg = 10^5 Pa

Question 50

Homotropic regulation (HR)

Answer 50

HR: when a molecule serves as a substrate for it’s target enzyme, as well as a regulatory molecule of the enzyme’s activity

• O2 = homotropic allosteric modulator of Hb
• HR is what causes Hb graph to have sigmoidal shape

Question 51

why is hydrostatic pressure (Hp) for liquids linear, but not for gases?

Answer 51

• Hp for liquids remains linear b/c the density of the fluid doesnt change at different depths
• the density of gases vary depending on the forces applied to them—»gases are compressible while liquids are not

Question 52

deposition

Answer 52

• phase change from gas to solid
• exothermic

Question 53

if an indicator dyte is needed for a titration of acetic acid w/NaOH, what should the pH of the indicator be?

Answer 53

• b/c acetic acid = weak acid, and NaOH = strong base, the pH at the titration endpoint would be expected to be greater than 7

Question 54

equation to calculate unknown concentration or volume for a titration

Answer 54

NaVa = NbVb

• N: normality (mol/L)—»molarity must be converted to normality for polyprotic acids/polyvalent bases

Question 55

If a person is excercising against a 50-W load for 5 min, what is the total work performed by the muscle?

Answer 55

• P=Wt
• W = P/t = (50J/s)/(300s) = 150 kJ

Question 56

1. what equation allows you to determine the percent remaining for a decaying isotope if the number of half lives is given? 2. if you are told that a sample of 2000g must be replaced when the mass decays to 250, given the info from question (1) how would you detemine the number of half lives to reach that point?

Answer 56

1. (0.5^n) = % remaining [n: # 1/2 lives]
2. 250/2000 = 1/8 (1/8) = (1/2)^n

Question 57

Formula for Mechanical Advantage of an inclined plane

Answer 57

MA = hypotenuse/height

Question 58

If each coupling step for a 10AA peptide produced a 95% yield, what would be the final yield for the peptide?

Answer 58

(0.95)^9 = 0.63 ≈ 60%

**only raised to a power of 9 b/c the cycle would only be run 9 times for a 10 AA peptide

Question 59

the flow rate of a heart valve is 4E^-4 (m^3/s). what speed would result within a blood vessel w/a cross sectional area of 5E^-6 (m^2)?

Answer 59

**UNITS**

• Q = Av
  
  • v = Q/A
  • (4E^-4) / (5E^-6) = 8E^-2 (m/s)

Question 60

Pyruvate Dehydrogenase Complex

Answer 60

1. Converts pyruvate—»acetyl CoA -generates 1 NADH
2. complex of 3 enxymes
   a) pyruvate dehydrogenase
   b) dihydrolipoyl transacetylase
   c) dihydrolipyl dehydrogenase
3. Requires 5 coenzymes:
   a) TPP b) FAD c) NAD d) CoA e) lipolate

Question 61

Surfactant

Answer 61

1. amphipathic molecules (hydrophilic head and hydrophobic tail)
2. surfactant adsorbs to air-water-alveoli interface—»reducing surface tension and total force resisting expansion

• elastic recoil force of the airway and surface tension of water lining the airway oppose expansion of alveoli—»surfactant reduces the force needed to expand alveoli

Question 62

Inspiration

Answer 62

1. contraction of diaphram & external intercostal muscles—»results in dec. in intrapleural pressure (neg. presure)
2. Neg. presure (rel. to Patm at entry to airway) causes airflow through respiratory tract to end at alveoli

Question 63

What is the equation for the gibbs free energy change of a phase change from liquid to solid?

Answer 63

∆G = G(l) - G(s)

∆G = ∆H -T∆S

• ∆H = enthalpy of formation
• ∆S = entropy of formation

Question 64

Quantum Numbers/Electron Configuration

Answer 64

1. principle quantum number (n): energy level of the e- •higher n = higher energy
2. Angular (azimuthal) momentum # (l): subshell of n •l = n–1 • s=0, p=1, d=2, f=3
3. Magnetic quantom # (ml): •ml = (-l), 0, (+l)
4. Spin quantum number (ms): spin orientation •ms = +/- 1/2

Question 65

equation to calculate the energy of an electron’s n level

Answer 65

En = -Rh/(n^2) Rh

(Rydberg Constant) = different for each element

Question 66

what is range in wavelength for the visible spectrum of electromagnetic signals? what color does each end correspond to?

Answer 66

1. Range = [400nm - 700nm]

• 400nm = purple (high energy)
• 700nm = red (low energy)

Question 67

if isotpe X & Y both undergo B- decay, what is the expected ratio of total atomic mass of material X vs. material Y?

• half life X = 5 years
• half life Y = 1 year

Answer 67

1. Ratio = 1:1

•the atomic mass of an atom doesnt change when B- decay takes place b/c the transition from neutron to proton has a negligible change in atomic mass

Question 68

If an electron were ejected from an sp, sp2, or sp3 porbital, which of these would emit electromagnetic radiation w/the shortest wavelength?

Answer 68

sp orbital—»shorter wavelength emissions correspond to higher energy electromagnetic emmissions ∴ b/c it would require the most energy to eject an electron from an sp orbital, it would have the shortest wavelength

Question 69

Hertz

Answer 69

Hz, Frequency s^-1

Question 70

Newton

Answer 70

N, Force, kg m/s^2

Question 71

Pascal

Answer 71

Pa, Pressure, N/m^2

Question 72

Joule

Answer 72

J, Work/Energy, Nm

Question 73

Newton-meter

Answer 73

Nm, Torque

Question 74

Watt

Answer 74

W, Power, J/s

Question 75

Coulomb

Answer 75

C, Charge

Question 76

Volt

Answer 76

V, Electric potential, J/C

Question 77

Farad

Answer 77

F, Capacitance, C/V

Question 78

Ohm

Answer 78

(Omega), Resistance, V/A

Question 79

Weber

Answer 79

You don’t need this, seriously

Question 80

Tesla

Answer 80

T, Magnetic field

Question 81

Y32 is a genetically encoded fluorescent biosensor, and the spectral ratio of peaks of excitation spectrum are a direct representation of ATP-ADP ratio. If its proposed that differences in ATP-ADP ratios are due to variations in Y32 expression, would the student be correct?

Answer 81

• NO—» Y32 fluorescent intensity ratio of peaks is a reflection of its ATP-ADP ratio
• use of ratio = intrinsic normalization—»∴ doesnt matter how many biomolecules are in the sample, the ratio provides normalization that makes the values reliable

Question 82

Whats the most likely cause of a shift in the emission spectra of a fluorescent molecule where wavelength increases?

Answer 82

an inc. in wavelength corresponds to a dec. in energy —» loss of energy occurs when e- returns to ground state b/c it was excited w/the same amount of energy that would have produced the first emission spectrum .

Question 83

if a fluorescent molecule is pH-sensitive, why might this cause problems when using it to monitor changes in the energy balance of a cell?

Answer 83

pH will change over time in a cell, and changes to emission spectrum might be reflection of the change in pH and not whatever it is supposed to be indicating

Question 84

If log(MW) = n, what is the molecular weight of that molecule equal to?

Answer 84

MW = 10^n [Da]

Question 85

If the pKa of a weak acid = 3.5, what would be the most accurate guess for the pH of a [.1M] solution? -1.0, 2.3, 3.5, or 4.1?

Answer 85

• 2.3
• if it were a strong acid then pH = 1
• if [HA] = [A-] then pH = pKa = 3.5

Question 86

Calculating Galvonic cell potential

Answer 86

1. galvanic cell = spontaneous rxn 2. cell potentials (Eº) always > 0 [i.e.(+)] 3. if given the reduction potential for both components of the galvonic cell—»reverse the sign of the less positive reduction potential (i.e. oxidation potential) •then simply add the ox/red potentials directly —» Eº = Eºr + Eºo

Question 87

Ohm’s Law

Answer 87

V = IR

Question 88

Capacitance equation & Units

Answer 88

• C = Q/V = κε₀A/d
  
  • k = dialectric constant
    
    • [κ ∝ C] —» Q_κ = 4Q₀ when dialectric constant is added to a capacitor
  • ε₀ = constant (not needed for MCAT)
  • A = area of the plates
  • d = distance between plates
• Capacitantce must always be (+)
• Unit: farads (F)
  
  • q: coulomb (C)
  • V: volt (V)

Question 89

Phosphorus Acid Molecular Formula

Answer 89

H3PO3

Question 90

Difference between ‘-ous’ acids vs. ‘-ic’ acids?

Answer 90

1. “-ous”: acids have 1 fewer O atam than “-ic” counterpart acid
2. Ex: Phosphorous Acid (H3PO3) vs. Phosphoric Acid (H3PO4)

Question 91

Ksp

Answer 91

1. Ksp (solubility product) = [A-]^2[B^2+]

• (A-) & (B2+) = two ions of aq ionic compound
• ion concentration raised to the power of its stoichiometric coefficient

2. High Ksp=more soluble | Low Ksp = less soluble

Question 92

If a mechanical leg mimics a spring’s compression, and it absorbs 125J of KE after compressing 10cm, whats the spring constant?

Answer 92

1. leg absorbing KE and converts to elastic potential enerfy
2. KE = 1/2kx^2 • k = 2KE/x^2 | k = 25,000 N/m

Question 93

What is the relationship of volume and temperature for an ideal gas? (P is kept constant)

Answer 93

1. direct relationship (when pressure is constant)
2. V1/T1 = V2/T2

• T must be in Kelvin (K)

Question 94

What are the units required for temperature whenever dealing with an ideal gas?

Answer 94

Kelvin

Question 95

Answer 95

Question 96

Answer 96

Question 97

On what basis does gas-liquid chromatograph separate compounds?

Answer 97

Vaporizes the compounds. The first peaks exhibit the lowest molecular weight and intermolecular forces.

Question 98

What is the thin lens formula?

Answer 98

The strength of the eye lens is given as the inverse of the focal length of the eye lens. 1/O + 1/I = S . O stands for the distance someone can see objects. I is the lens to retina distance.

Question 99

How do you calculate the index of refraction?

Answer 99

It is equal to the ratio of the speed of light in a vacuum / the speed of light in the medium

Question 100

What is intensity of radiation proportional to?

Answer 100

The number of photons emitted

Question 101

What is the difference between threonine and serine?

Answer 101

Threonine has a secondary alcohol while serine has a primary alcohol

Question 102

What is the hybridization of an octahedral compound?

Answer 102

sp3d2

Question 103

What bond does glycogen synthase catalyze?

Answer 103

The a-1,4-glycosidic linkage of an individual glucose molecule to the main chain of glycogen

Question 104

How can you use the thin lens equation to find the height of an image?

Answer 104

1/o + 1/i = 1/f . You can calculate the distance (i) of an image if you know F and O. The height of an image is the ratio of i/o

o: object distance
i: image distance
f: focal length

Question 105

What is +∆S?

Answer 105

An increase in entropy and more disorder as if 2 reactants became 3 products

Question 106

What will occur if a homogenous catalyst cannot be separated from the products at the end of a reaction?

Answer 106

The reaction will still occur, but the products will be contaminated with the catalyst

Question 107

Name the strong acids:

Answer 107

HCl, HNO3, HI, HClO4, HClO3

Question 108

Name the strong bases:

Answer 108

KOH, NaOH, Ba(OH)2, CsOH, Sr(OH)2, Ca(OH)2, LiOH, RbOH

Question 109

Express the amount of light energy that is converted to other forms between the flouescence excitation and emission events in J/photon:

Answer 109

E=hc/(1/ye-1/yf)

Question 110

How do you calculate Kcat?

Answer 110

Kcat = Vmax/[E]

Question 111

Absorption of UV light by organic molecules always results in what process?

Answer 111

Excitation of bound electrons

Question 112

What is the half life of radioactive material?

Answer 112

The time it takes for half of all the radioactive nuclei to decay into their daughter nuclei

Question 113

Which phosphate is used by kinases in phosphoryl transfer?

Answer 113

gamma-Phosphate

Question 114

How is cooperativity expressed in a graph?

Answer 114

A sigmoidal curve

Question 115

What phenomenon causes static air to be drawn into the mask when oxygen flows?

Answer 115

Venturi effect

Question 116

Why do G-C residues have higher boiling points than A-T residues?

Answer 116

G-C bonds exhibit a higher π-stacking strength

Question 117

What are the difference between phospholipids and storage lipids?

Answer 117

Phospholipids consist of a glycerol molecule with two fatty acid tails, and a phosphate group modified by an alcohol. Storage lipids have three fatty acid tails ester linked to a single glycerol

Question 118

What are Lewis bases?

Answer 118

Lone pair donors

Question 119

What is a coordinate covalent bond?

Answer 119

A lewis acid-base interaction between a metal cation and an electron pair donor

Question 120

What will HCl react with first: ammonia or water?

Answer 120

NH3 because it is a much stronger base

Question 121

What is the coordination number?

Answer 121

The number of molecules that coordinate covalent bond to a central metal cation

Question 122

What is henderson hasselbach formula for acids and what is 10^-1?

Answer 122

pH=pKa+log[base/acid] ; 10^-1=.1

Question 123

What is the solubility product constant expression for CaCO3? What is the concentration of a saturated solution of CaCO3 if the Ksp=4.9*10^-9?

Answer 123

Ksp=[Ca][CO3] ; if the Ksp is 4.9*10^-9 then [Ca] is the sqrt of that: 7*10^-5

Question 124

What is the difference in sound intensities between 20 and 40dB?

Answer 124

A difference of 20dB is 2 factors of 10 so 100 times more intense

Question 125

How is energy converted in a battery that has a resistor?

Answer 125

Chemical to electrical to thermal energy

Question 126

What is the bond formed by protein secondary structure?

Answer 126

Hydrogen bonds between the backbone amide protons and carbonyl oxygens

Question 127

What is the magnification formula and what would the di be for an object 20cm to the left of a lens?

Answer 127

M = -di/do . to the left of the lens the image has a negative value

Question 128

Where does a real image form?

Answer 128

To the opposite side of the lens as the object

Question 129

Why is the change in frequency & wavelength so much greater for sound waves vs. radio waves?

Answer 129

1. [∆f/f = -v/c]
2. sound waves travel slower (lower v) than radio waves

– ∆f inversly dependent on the speed of the wave in the medium it propogates

– ∴ since the v of sound < v of radio —» the same relative velocity will produce shifts in frequency and wavelength that are much greater for sound than radio waves

Question 130

Equation for electric field (E) that relates V, I, R, & L

Answer 130

E = (V – IR) / L

Question 131

if the # of incident photons changes on the cathode (w/energies above the value of the work function) what quantity would also increase?

Answer 131

incident photons affects only the # of e- ejected (NOT THEIR ENERGIES) —» inc. the # of incident photons = inc. # e- ejected

Question 132

If given a list of different compounds, how could you predicte which of these compounds would appear as the first peak for mass spectroscopy?

Answer 132

molecules with the lowest molecular weight and weakest intermolecular forces of attraction will migrate the fastest and become the first peak

Question 133

If given a list of different compounds, how could you predicte which of these compounds would appear as the first peak for mass spectroscopy?

Answer 133

molecules with the lowest molecular weight and weakest intermolecular forces of attraction will migrate the fastest and become the first peak

Question 134

What are the properties of an ideal gas?

Answer 134

1. individual molecular volume and intermolecular forces are negligible 2. One mole of gas occupies a volume of 22.4L at 0ºC at 1atm

Question 135

What is the change in oxidation state as NH3—»NH4+?

Answer 135

No change to oxidation state—»acid/base rxns dont affect oxidation # of an atom

Question 136

__ eV = __ J ?

Answer 136

1eV = 1.6E-19 J

Question 137

Can 3º alcohols be oxidized into a ketone? why/why not?

Answer 137

oxidation of a 3º alc is unlikely b/c it involves breaking a C-C bond (very difficult)

Question 138

Amine

Answer 138

N(R)3 —» R = C or H

Question 139

What is the equation for potential energy of a capacitor?

Answer 139

U = (1/2)CV²

C = Capacitance

V = Voltage

Question 140

Suppore a railcar passes by a horn emitting a sound w/frequency f. If f’ is the frequency heard by the person on the cart, what is the relationship between f & f’ before and after passing the horn?

Answer 140

f’ > f before passing the horn, f’ < f after passing it

Question 141

Units of Power

Answer 141

SI UNIT: Watts

1W = J/s = V•Amp

Question 142

Power Equation

Answer 142

1. P = W/t

• W = work
• t = time

2. P = VI

• V = voltage
• I = current

3. P = Fv

• F = force (N)
• v = velocity (m/s)

Question 143

What experimental data is used to determine the thermodynamic stability of isomeric organic compounds?

Answer 143

1. Heats of Combustion—»the energy released when something is burned. When you have more -CH2 groups, then there is more energy released when burning it
2. Only in isomers does the branching effect play a significant role.
3. More ring strain = higher heat of combustion

Question 144

Answer 144

Question 145

Answer 145

Question 146

Activation Energy Formula

Answer 146

AE = [the energy of the activated complex] – [the energy of the reactants]

Question 147

D-Block Elements and Filling e- Orbitals

Answer 147

Question 148

Experimental Conditions Needed for Michaelis-Menten Kinetics

Answer 148

1. initial velocity is measured under steady-state conditions
2. the concentration of enzyme is lower than that of substrate
3. solution pH remains constant at all substrate concentrations

Question 149

Hydroxamic Acid Structure

Answer 149

Question 150

pK

Answer 150

the pH at which the fraction of folded DNA is 0.5

Question 151

Answer 151

Question 152

Answer 152

C: Na2CO3 is a bronsted base

Question 153

Carbomate Amide Grp

Answer 153

Question 154

Ping Pong (double-displacement) Binding

(no tertiary complex)

Answer 154

Question 155

Random Order Substrate Binding

Answer 155

Question 156

Ordered Substrate Binding

Answer 156

Question 157

What is the acceptable range for a certain buffer with a given pKa value?

Answer 157

±1 pH value

Question 158

Phosphorylation of AA w/ATP (mechanism)

Answer 158

Question 159

Phosphoric Acid vs. Inorganic Phosphate (Pi) vs. Inorganic Pyrophosphate (PPi)

Answer 159

Question 160

Structure of ATP

Answer 160

Question 161

Kcat

Answer 161

1. Vmax/(Etotal)
2. turnover number (s^-1)

Question 162

kcat/Km

Answer 162

Measure of enzyme’s catalytic efficiency

Question 163

Michaelis–Menten Graph
A) Vmax B) Km C) [V] vs. [S]

Answer 163

Question 164

Vmax1. represents the maximum rate achieved by the system (at saturating substrate concentrations)
2. Units: mol/s

Answer 164

1. represents the maximum rate achieved by the system (at saturating substrate concentrations)
2. Units: mol/s

Question 165

Refraction & Snell’s Law

Answer 165

Question 166

polarization

Answer 166

Question 167

diffraction

Answer 167

Question 168

Current (I) —» Units & Equation1. I = flow of charge/unit time
• I = [charge(q)]/[time(t)]
2. Unit: Ampere [C/s]

Answer 168

1. I = flow of charge/unit time
   • I = [charge(q)]/[time(t)]
2. Unit: Ampere [C/s]

Question 169

Capacitor

Answer 169

Question 170

Action Potential

Answer 170

Question 171

Graded Potentials

Answer 171

1. Graded potentials are brought about by external stimuli (in sensory neurons) or by neurotransmitters released in synapses, where they cause graded potentials in the post-synaptic cell.
2. occur in the cell body and dendrites (not axon)
3. no refractory period
4. summed over time (temporal summation) and accross space (spatial summation)
5. no refractory periods
6. ion channels responsible for graded potentials may be ligand-gated (i.e. NTs), mechanosensitive, or temperature sensitive

Question 172

Action potentials vs. graded potentials

Answer 172

Question 173

What is the relationship between absorbance and concentration

Answer 173

1. absorbance is directly proportional to concentration
2. any absorbance greater than 1 —» then the proportionality starts to change

Question 175

Base Catalyzed Ester Hydrolysis (Saponification)

Answer 175

Question 176

Acid Catalyzed Hydration

Answer 176

Question 177

Phosphotase

Answer 177

Question 178

3 Layers of the Skin

Answer 178

1. Epidermis: outermost layer of skin—»provides waterproof barrier and skin tone
2. Dermis: connective tissue, hair follicles, and sweat glands
3. Hypodermis: subcutaneous tissue made of fat and connective tissue

Question 179

Epidermis

Answer 179

1. composed of keratinized, stratified squamous epithelium—»lacks vasculature
2. Layers:
   
   1. stratum corneum: dead cells filled with keratin
   2. Stratum lucidum: thin layer of cells is found only in the thick skin of the palms, soles, and digits
   3. Stratum granulosum: Lamellar granules
   4. stratum spinosum:
      
      1. join the cells via a structure called a desmosome.
      2. contians keratinocytes & langerhan cells
   5. stratum basale:
      
      1. deepest epidermal layer and attaches the epidermis to the basal lamina
      2. Merkel cells—»functions as a receptor for stimulating sensory nerves for touch
      3. Melanocyte—»produce pigment melanin

Question 180

Dermis

Answer 180

1. Papillary Layer: made of loose, areolar connective tissue, which means the collagen and elastin fibers of this layer form a loose mesh
   
   1. contains fibroblasts, fat cells, small blood vessels, lymphatic capillaries, phagocytes, and Meissner corpuscles
2. Reticular Layer: composed of dense, irregular connective tissue
   
   1. well vascularized
   2. elastin fibers provide elasticity to skin, collagen fibers provide tensile strength

Question 181

Hypodermis

Answer 181

1. subcutaneous layer that serves to connect the skin to the underlying fascia (fibrous tissue) of the bones and muscles
2. well-vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation

Question 182

Answer 182

Imine—» nitrogen atom connected to a carbon atom w/a double bond

Question 183

Answer 183

Question 184

Michaelis-Menten equation

Answer 184

Question 185

Lac Operon

Answer 185

1. inducible system: repressor is bound in the abscence of lactose
   
   1. w/lactose—»allolactose bind repressor and transcription can occur

Question 186

Furanose vs. Pyranose ring structure

Answer 186

Question 187

Mutarotation of Glucose

Answer 187

Question 188

Anomeric Carbon

Answer 188

Question 189

If lactate dehydrogenase was removed from this reaction, what would happen to the free energy value shown for the formation of L-Lactate?

Answer 189

• it would not change
• enzymes inc. the rate of a rxn, but dont change the thermodynamic properties—» ∴ enzymes dont change the free energy of a rxn

Question 190

Volume Flow Rate Equation

Answer 190

• Q = V/t = Ad/t = Av
  
  • Q = volume flow rate
  • A = cross-sectional area
  • v = speed of fluid

Question 191

when an object is [closer/farther] to a convex lens than the focal point, the lens will create a virtual image

Answer 191

closer to the lens than the focal pt = virtual image

Question 192

Magnification formula for lens

Answer 192

• M = -d_i/d_o
  
  • d_i = distance of image
  • d_o = distance of object

​https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/thin-lens-quiz-passage-1

Question 193

Equation for lens strength

Answer 193

• P = 1/f
  
  • ​P = lens strength
  • f = focal point (MUST BE IN METERS)
  • Unit = Diopeter (m^-1)

https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/thin-lens-quiz-passage-1

Question 194

how would you describe the objective and eyepiece images from this compound microscope setup?

Answer 194

• Objective: real, inverted, enlarged
• Eyepiece: virtual, inverted, enlarged

https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/analysis-of-image-production-by-the-human-eye

Question 195

Optical properties of the eyes

identify labels & address how image is formed by eye.

Answer 195

Question 196

What is the image size of a 6-foot tall man (1.8 m) who is standing at a distance approximately 10 feet away (3.0 m) on the human retina?

Answer 196

• h_i/h_o = (–)d_i/d_o
  
  • (h_i)/(1.8m) = (.02m)/(3m)
  • h_i = .036/3 = 0.012m

https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/analysis-of-image-production-by-the-human-eye

Question 197

Accommodation is the process of adjusting the focal length to view objects at varying distances. What is the range in power of the eye in diopters when viewing from the closest (d = 25 cm) to the farthest possible distance from the eye?

Answer 197

• 1/f = 1/i + 1/o, so P = 1/i + 1/o.
  
  • P at closest distance: P = 1/.25 + 1/0.02 = 4 + 50 = 54
  • P at farthest distance: P = 1/∞ + 1/0.02 = 0 + 50 = 50
• Range in Power of the Eye = [54 - 50] = 4 Diopeters

https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/analysis-of-image-production-by-the-human-eye

Question 198

Ray diagram for a telescope

Answer 198

Question 199

chromatic abberation

Answer 199

• Shorter wavelengths experience a greater index of refraction, so blue converges closer to the lens than red.
  
  • The refractive index tends to decrease with increasing wavelength and subsequently increase with frequency.
  • Blue experiences a greater index of refraction and travels more slowly in the material, & red experiences the lowest index of refraction and travels more quickly.
    
    • Since blue experiences the greater refractive index, blue will converge closer to the lens than red will

Question 200

Dispersion

Answer 200

• the change of index of refraction with wavelength
  *

Question 201

Emmetropia vs. myopia vs. hyperopia

Answer 201

1. emmetropia: eye w/no refractive errors
2. Myopia: nearsightedness—»focus nearby obj. but not distant obj.
3. Hyperopia: farsightedness—»focus on distant obj. but not nearby obj.

Question 202

1. what causes myopia?
2. which of these 4 changes would contribute to myopia?
   
   1. inc. in eye’s axial length
   2. inc. in refractive index of lens
   3. inc. in diameter of pupil
   4. inc. in curvature of cornea

Answer 202

1. myopia results when the focal length of eye is less than the axial length
   
   1. ∴ anything that shortens focal length or lengthens axial length = myopia
2. inc. in diameter of pupil—»only inc. amt of light entering eye, doesnt affect axial or focal length
   
   1. inc. curvature of cornea or inc. refractive index = shortened focal length

Question 203

what lens corrects for hyperopia?

Answer 203

• hyperopia: focal length of eye is greater than axial length
• converging lens—» refract light before it enters eye and allows light to converge at the retina

Question 204

The optical power of the average human eye is 60 Diopters. Approximately, what is the height of the inverted image produced on the retina of a 1 meter tall child standing 10 meters away from a human eye?

Answer 204

• P = [1/d_o] + [1/d_i]
  
  • 1/d_i = 599/10
• m = -d_i/d_o
  
  • m = [–(10/599)/10] = -1/599
• -d_i/d_o = h_i/h_o = -1/599
  
  • h_i = -1/599 ≈ -1/600
  • [(-) means that img. is inverted]

https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/the-refraction-of-light-through-the-human-eye

Question 205

Doppler Effect

If an object is moving away from a reciever will __________ in pitch, while objects moving towards a receiver will __________ in pich.

Answer 205

If an object is moving away from a reciever will decrease in pitch, while objects moving towards a receiver will increase in pitch.

Question 206

if the speed of an ultrasound docked on a car is constant, how does the frequency and volume change as the US approaches a person?

Answer 206

• speed is constant ∴ the Doppler shift is constant and the frequency remains constant
• intensity of signal inc. as US approaches person ∴ volume inc.

Question 207

Intensity Formula & Units (E&M)

Answer 207

1. I = P/A
   
   1. P = Power (W)
   2. A = Cross Sectional Area (m²) = 4πr²
2. I ∝ 1/r²

Question 208

Doppler Equation

Answer 208

Question 209

Concave mirrors

1. For a real object very far away from the mirror, the _____ image is formed at the ______.
2. For a real object close to the mirror but outside of the center of curvature, the _______ image is formed __________ The image is ________ and [larger/smaller] than the object.

Answer 209

Question 210

Concave mirrors

1. For a real object at f, ________ image is formed. The reflected rays are _________ and _______ _________.
2. For a real object between f and the mirror, a ______ image is formed _____________. The image is ________ and [bigger / smaller / same size] than/as the object.

Answer 210

Question 211

Concave mirrors

1. For a real object at C, the ________ image is formed at ___. The image is _______ and [bigger / smaller / same size] as the object.
2. For a real object between C and f, a ______ image is formed _____________. The image is ________ and [bigger / smaller / same size] than/as the object.

Answer 211

Question 212

Convex Mirror Diagram

Answer 212

• convex mirrors always produce virtual & right side up images
• images outside of f & C will focus parallell light rays to the prinicipal axis—»all rays converge at f

Question 213

If a titration curve shows 2 equivalence points, the acid titrated is most likely…?

Answer 213

Diprotic

Question 214

As one moves across the periodic table from right to left, atomic radius ­­______ and electronegativity ______.

Answer 214

• atomic radius = inc. (down and left along periodic table)
• electronegativity = dec. (down and left along the periodic table)

Question 215

Which atom has the smallest radius?

1. K+
2. Ar
3. Cl-

Answer 215

K⁺ —» contains most [H+] atoms = stronger attractive force and ∴ smallest radius

Question 216

Which groups of atoms on the periodic table must be stored in an inert gas in order to prevent dangerous exothermic reactions with the atmosphere?

Answer 216

• alkali metals & alkaline earth metals
  
  • alkali metals = most volatile b/c small 1st ionization energy

Question 217

isoelectric species

Answer 217

• isoelectric species have same # of electrons
• ex: Cl^- & Ca²⁺

Question 218

1. how to calculate gram equivalent weight?
2. gram equivalent weight of phosphoric acid?

Answer 218

1. Gram Equivalent Weight (for acid) = mass/acidic proton
2. H₃PO₄ = 98 g/mol

• 98g/mol ≈ 100g/mol –» 100_g/mol / 3_[H+] = 33g
• Gram equivalent weight H₃PO₄ = 33g

Question 219

What is the approximate angle between adjacent bonding electrons in XeF4?

Answer 219

90°

Question 220

Ideal Gas Behavior

Answer 220

1. low mass
2. weak intermolecular forces
   
   • EX: HCl & CH₄
3. Conditions:
   
   • Low pressure and high temperature

Question 221

C2H6 + O2 → CO2 + H2O

If 4 moles of ethane gas is placed in a sealed chamber with 10 moles of oxygen gas, which species is the limiting reagent?

Answer 221

1. first step is to balance the equation:
   
   • 2C2H6 + 7O2 → 4CO2 + 6H2O
2. next find —» ratio of moles:coefficient for 2 reactants
   
   • Ethane’s ratio = 4:2
   • Oxygen’s ratio = 10/7 —» smaller ratio ∴ O2 is the limiting reagent

Question 222

A solution of acetic acid has a pH of 6.2. What is the approximate molar concentration of protons in the solution?

A) 8 x 10^-8 M

B) 8 x 10^-7 M

C) 8 x 10^-6 M

D) 8 x 10^-5 M

Answer 222

B) 8 x 10^-7 M

• pH of 6 corresponds to an H+ concentration of 10^-6 M
• pH of 6.2 is slightly less acidic —» 8 x 10^-7 is slightly less than 10^-6.

Question 223

Nitrate vs. Nitrite (structure)

Answer 223

Question 224

Difference between an exothermic rxn and a spontaneous rxn?

Answer 224

• Spontaneous:
  
  • ​[–∆G] = spontaneous
  • proceeds w/out any additional energy needed
• ​Exothermic:
  
  • ​[–∆H] = exothermic
  • net release of heat from system

Question 225

In the formation of water from oxygen and hydrogen gas, consider the following bond enthalpies:

H-H 436 kJ/mol

O=O 499 kJ/mol

O-H 463 kJ/mol

This reaction can be classified as:

Answer 225

1. rxn must be determined and balanced
   
   • 2H₂ + O₂ → 2H₂O
2. ΔH_rxn = Σ[ΔH_reactants] – Σ[ΔH_products]
   
   • ΔH_rxn = [2(436) + 499] – [4(463)] = -481 kJ/mol

Rxn = Exothermic

Question 226

Faraday’s Constant

Answer 226

• Farday’s constant = charge of 1 mol of electrons
• F = 9.65x10⁴ Coulombs

Question 227

The reduction half-reaction for the silver cation is Ag+ + e- → Ag(s). This process is used to electroplate an object using silver from solution.

How long will it take to deposit 21.6 g of silver, given a current of 100 A?

Answer 227

• 21.6g Ag = 0.2 mol Ag
• 100 A = 100 C/s
  
  • C: coulomb
• (0.2 mol)(9.65 x 10⁴ C/mol) = 1.9 x 10⁴ C
  
  • (1.9 x 10⁴ C)/(100 C/s) = 190 seconds

Question 228

Galvonic & Electrolytic Cells

which is spontaneous vs. non-spontaneous?

Answer 228

• Galvonic Cells—» spontaneous
  
  • e^- move spontaneously from anode to the cathode
• Electrolytic Cells—» non-spontaneous

Question 229

what is the purpose of a salt bridge in a galvonic cell?

Answer 229

serves to prevent the accumulation of (+) charge at the anode

Question 230

which group of the periodic table forms (-2) ions and covalent bonds?

Answer 230

Chalcogens —» column 16 of the periodic table elements

• oxygen, sulfur, etc.

Question 231

Gas —» Solid

[Phase Change?]

Answer 231

Deposition

Question 232

How to calculate molar solubility when given Ksp?

EX: What is the molar solubility of an insoluble solid, AB, if the Ksp for AB is 8.3 x 10^-11?

Answer 232

• Ksp = [A+][B-]
  
  • Ksp = x²
  • 8.3 x 10^-11 = x²
  • x ≈ 9 x 10^-6 mol/L

Question 233

How to predict reaction direction when given the rxn quotient (Qc) and equillibrium constant (Keq)?

Answer 233

Question 234

What is absolute 0° in Kelvin and Celcius?

Answer 234

• 0 Kelvin
• -273 °C

Question 235

adiabatic expansion/compression

Answer 235

• adiabatic curves —» no heat is exchanged, but work is done on or by the system
• [Graph] —» Curve B is adiabatic EXPANSION b/c volume is inc.

Question 236

How does adding an enzyme affect the Keq of a rxn?

Answer 236

Enzymes only affect the rate of rxn ∴ enzymes dont affect Keq

Question 237

What will be the effect on the pH of 1 L of pure water at 298 K if heat is added to the system?

Answer 237

• H₂0 —» H⁺ + OH^- = ENDOTHERMIC process
• adding heat = adding energy ∴ H2O will dissociate into H+ and OH- ions
  
  • pH of H2O would still be neutral, but pH & pOH both dec.
  • pH + pOH ≠ 14 —» pH + pOH = pK_w​ (pH + pOH not always = 14)
    
    • inc. temp of H2O also inc. Kw ∴ pKw dec. allowing both pH and pOH to dec.
• the pH will dec. when heat is added to the H2O

Question 238

Gabriel Synthesis

Answer 238

• Nucleophile: nitrogen of a phthalimide molecule acts like a nucleophile
• Electrophile: secondary carbon of an alkyl halide.

Question 239

Rxn w/COOH as reactant

Answer 239

Question 240

what is the reactant/product of an aldol condensation

Answer 240

Question 241

which of these molecules is the keto form and which is the enol form?

what molecule is more abuntant?

Answer 241

• keto form is always more stable, and ∴ more abundant than the enol form
  
  • HOWEVER —» special exceptions to this rule (i.e. cases in which formation of the enol confers aromaticity on the molecule)

Question 242

Draw the structure of a hemi-ketal and hemi-acetal

Answer 242

Question 243

Are K₂Cr₂O₇ & O₃ strong or weak oxidizing agents?

They convert alcohols ——» [???]

Answer 243

• strong oxidizing agents
• alc —» COOH

Question 244

UV-Vis Spectroscopy

[LUMO & HOMO]

Answer 244

• UV spectroscopy is most useful for studying compounds containing double bonds and/or heteroatoms with lone pairs that create conjugated systems.
• LOMO: lowest unoccupied molecular orbital
  
  • the higher-energy position where an electron that has absorbed a photon of sufficient energy will be found
• HOMO: highest occupied molecular orbital
  
  • lower-energy orbital

Question 245

Elemental nitrogen does not exhibit an IR spectrum because it…

Answer 245

is symmetrical

Question 246

What shifts would indicate the presence of a carboxylic acid proton in a 1H-NMR spectrum?

Answer 246

11.0 ppm

Question 247

Infared Radiation Frequency Range

Answer 247

[10¹² – 10¹⁴] Hz

Question 248

Visible Light Frequency Range

Answer 248

10¹⁵ Hz

Question 249

UV Light Frequency Range

Answer 249

[10¹⁵ – 10¹⁶] Hz

Question 250

Gamma Ray Frequency Range

Answer 250

[10¹⁹ – 10²⁰] Hz

Question 251

X-Ray Frequency Range

Answer 251

[10¹⁷ – 10¹⁸] Hz

Question 252

Radio Wave Frequency Range

Answer 252

10⁸ Hz

Question 253

Microwave Frequency Range

Answer 253

[10⁹ – 10¹¹] Hz

Question 254

A two-pulley system allows a dockworker to apply a 1000 N force over a distance of 10 m, while lifting a crate by a vertical distance of 7.5 m. If the crate is raised at a constant speed and friction and resistance are negligible, what is the weight of the crate?

Answer 254

• Work = (1000N)(10m) = 10,000J
• 10,000J = F(7.5m)
  
  • F = 1300N

Question 255

The portion of an object submerged in water is the same as it’s ______ _______?

Answer 255

Specific Gravity

Question 256

Equation relating the speed of flow and cross-sectional area in a pipe system.

Answer 256

A_{<span>1</span>}V_{<span>1</span>} = A₂V₂

Question 257

A toy boat constructed of balsa wood (c = 0.7 J/g °C) is set in 1 L of hot water (c = 4.2 J/g° C). If all the water is brought into thermal contact with 1 kg of balsa wood that is 30 degrees lower in temperature, how much will the temperature of the wood increase (°C)?

Answer 257

Question 258

The specific heat (c) of wood is much lower than that of water, ∴ the wood should experience a greater _________ in temperature.

Answer 258

Increase

Question 259

If a noise machine requires 100 W to produce a continuous 10-dB sound, how much power is needed to produce a continuous 80-dB sound?

Answer 259

• 10 dB to 80 dB = Δ70 dB —» need to raise intensity by factor of 10⁷
• I₀ = 10² W
  
  • (10²)(10⁷) = 10⁹ W = 1000 MW.

Question 260

thin-film interference

Answer 260

EX: when light reflects off a bubble produces multiple colors

Question 261

What are the conditions that lead to total internal reflection?

Answer 261

Light must travel from a high index of refraction to a low index of refraction for total internal reflection to occur.

Question 262

For visible light, greater frequency / shorter wavelength = ______ refraction

Answer 262

MORE refraction

Question 263

white light separation as it passes through glass, which color of the visible light spectrum will experience the greatest deviaiton from the normal?

Answer 263

Violet—» higher f and shorter λ = greater refraction

Question 264

Power Equations

[in terms of V, I, & R]

Answer 264

• P = VI = V²/R = I²R
• how to minimize power loss…
  
  • Maximize voltage (V)
  • Minimize current (I)
  • Minimize resistance (R)

Question 265

Graff is selecting between two different pre-cut copper (ρ = 17.1 nΩ-m) wires. Wire A is 9 mm long, and has a cross-sectional area of 1 mm2. Wire B is 4.5 mm long, with a cross-sectional area of 2 mm2. How does the resistance of Wire B compare to Wire A?

Answer 265

• R = ρL/A
• Wire B has half the length and double the area, ∴ it will have ¼ the resistance

Question 266

Right Hand Rule

Answer 266

• always remeber to flip the sign/direction when working with (–) charges
  
  • RHR based on (+) charges

Question 267

Gauge Pressure Formula

Answer 267

• P_gauge = P_total - P_ATM

Question 268

the oscillation and wave propogation of sound waves are [// or ⊥]

Answer 268

Parallel [//] —» longitudinal wave

Question 269

B- Decay

Answer 269

Question 270

B+ Decay

Answer 270

Question 271

Types of Radioactive Decay

Answer 271

Question 272

1 atm = _______ Pa

Answer 272

1 atm = 101,000 Pa

Question 273

Convection vs. Conduction vs. Radiation

Answer 273

Question 274

Direction of Electric Current

Answer 274

• Current = flow of positive charges
• current flows from the negative terminal to the positive terminal and continues in that direction
  *

Question 275

If no other ions are involved, how would decreasing the concentration of sodium outside the cell affect the graph of action potential?

Answer 275

• If the concentration of sodium is lower outside the cell, then the overall voltage will be decreased, because there is less of a difference in charge being separated across the membrane.
• If the concentration of sodium outside the cell is lower than it was previously, and no other ions are involved then the current across the membrane will decrease, because this means the amount of charge is also less.
  
  • A decrease in current means the action potential will take a longer time.

Question 276

Noncompetitive Antagonist (what are the 2 examples?)

Answer 276

1. allosteric binding of an inhibitor to an enzyme
2. permanent active site binding.

Question 277

Methanol has a _______ boiling point and a ________ solubility in water than isopropyl alcohol.

Answer 277

lower, higher

Question 278

Tollen’s Test

Answer 278

• Tollens’ test, also known as silver-mirror test, is a qualitative laboratory test used to distinguish between an aldehyde and a ketone
  
  • exploits the fact that aldehydes are readily oxidized (see oxidation), whereas ketones are not (no Ag in tube if reaccted w/ketone)
• Rxn accompanied by the reduction of silver ions in Tollens’ reagent into metallic silver, which, if the test is carried out in a clean glass test tube, forms a mirror on the test tube

Question 279

what bonds does glycogen phosphorylase degrade?

Answer 279

catalyzes the hydrolysis of α-1,4-glycosidic linkage

Question 280

Glycogen

• Linkages?
• advantages to storing glycogen instead of straight chain glucose?

Answer 280

• 1,4 & 1,6 linkages
• advantages:
  
  • glycogen takes up less volume and preciptatle less easily than large unbranched polymers
  • doesnt inc. the osmolarity of the cell—»osmotic pressure inc. w/molarity
  • simultaneous sites for hydrolysis via branching

Question 281

An ideal simple machine, a machine that does not increase internal energy through friction, [does/doesn’t] change amount of work needed to move a load.

Answer 281

An ideal simple machine, a machine that does not increase internal energy through friction, does NOT change amount of work needed to move a load.

Question 282

Under icy conditions, which hill could a car park on without slipping?

Answer 282

• mgsinØ – µ_smgcosØ = 0
  
  • µ_s = tanØ
• The only hill that has a coefficient of static friction that is larger than the required coefficient is Austin Dr
  
  • tan(24°) = 0.445 which is less than 0.46

Question 283

A car is driving too fast up the hill on Austin Drive under icy conditions. After a deer runs across the road the driver of the car slams on the brakes, and the car skids up the hill.

When the car is skidding up the hill the forces of gravity along the incline and the force of friction point in the _______ direction.

Answer 283

• point in the same direction
  
  • mgsinØ + µ_kmgcosØ = ma

Question 284

According to the graph, at what time did the athlete’s feet lose contact with the ground?

Answer 284

• at 1 second—» V_max of a person will be attained right before the person leaves the ground.
  
  • acceleration after 1 second is -10m/s^{<span>2</span>} ∴ the person is in the air during that time accelerating only due to gravity.

Question 285

According to the graph, during which time interval did the athlete’s knees experience the largest upwards force?

Answer 285

• ∑F = ma
  
  • F_up – mg = ma
  • F_up = mg + ma —» knees will have the largest F_up when the acceleration has the largest positive value
• acceleration has the largest positive value between 2.0 – 2.1 sec ∴ knees experience the largest F_up

Question 286

Which of the following correctly describe the difference between an inverted pendulum (as shown in in Figure 1) and a standard pendulum with identical length and mass?

• I. An inverted pendulum has minimal kinetic energy when it reaches its equilibrium point
• II. An inverted pendulum requires a non-gravitational restoring force to remain in equilibrium
• III. An inverted pendulum reaches a higher maximum gravitational torque

Answer 286

• I and II are accurate statements
  
  • The kinetic energy is minimal when an individual is standing (equilibrium)
  • Standing requires the influence of the ankles (an external force) to maintain the otherwise unstable equilibrium

Question 287

In Figure 2, which of the following determines the frequency of the decaying oscillations?

Answer 287

The acceleration due to gravity sets the frequency of a simple pendulum, and so it determines the response time to equilibrate an inverted pendulum.

Question 288

What is the force of gravity exerted on the box?

Answer 288

40 N

[The fact that there are strings does not affect the calculation for the force of gravity on the box]

Question 289

What is the magnitude of the Tension in String B?

Answer 289

• ∑F = ma​
  
  • T_y – mg = 0
  • T_y = 40N ∴ …
• T_y = Tsin(30°)
  
  • T = T_y / sin(30°)
  • T = 40N / sin(30°)

Question 290

The graph shown below is for a trial where the copper mass rides in the elevator from the bottom floor to the top floor. The elevator starts from rest, gets up to speed, travels upwards with constant speed, then slows down and stops at the top floor.

What is the magnitude of the acceleration of the elevator between times t = 2sec and t = 3sec?

Answer 290

• ∑F = ma​
  
  • F_SCALE ​– mg = ma
  • 400N – 300N = 30(a)
  • a = 3.3m/s²

Question 291

The graph shown below is for a trial where the copper mass rides in the elevator from the bottom floor to the top floor. The elevator starts from rest, gets up to speed, travels upwards with constant speed, then slows down and stops at the top floor.

What is the magnitude of the acceleration of the elevator between times t = 8 sec and t = 9 sec?

Answer 291

• ∑F = ma​
  
  • F_SCALE ​+ mg = ma
  • 250N – 300N = 30(a)
  • a = | -1.7 m/s² | —» a = 1.7 m/s²

Question 292

Answer 292

• Since the object is placed in front of the diverging lens, it has no effect on the image.
• The object is placed within the focal length of the converging lens.
• Since the object is placed inside the focal length of the converging lens, the image will be virtual and to the left of point D.

Question 293

What is the formula and units for the strength of a lens?

Answer 293

• Lens Power (P): P = 1/f
  
  • ​f: focal length
• Units: m^-1 = Diopeter (D)

Question 294

Answer 294

Question 295

1. What is the value of angle θ₅?
2. The student now wants to change the lab set up to observe a total internal reflection event. Which of the following would increase the likelihood of seeing a total internal reflection event?
   
   1. Increase Ø₁
   2. Decrease Ø4
   3. Decrease Ø5
   4. Increase Ø3
3. Which of the following expressions is equal to the critical angle required for observing a total internal reflection event using this prism surrounded by air?

Answer 295

1. Remember to measure all angles from the normal line

• The angle in the prism from the normal line = (90 - θ₄)
• n₁sinØ₁ = n₂sinØ₂ ————»»» n_p(90°-Ø₄) = sinØ₅
  
  • Ø₅ = sin^-1[n_psin(90-Ø₄)]

1. Total internal reflection only happens when light would refract into a faster material
   
   1. Decrease Ø4
2. Total internal reflection first happens when the refracted angle is 90°
   
   • Use Snell’s Law with and set the refracted angle equal to 90∘∘
   • n₁sinØ₁ = n₂sinØ₂ ————»»» n_psin(Ø_C) = sin90°
     
     • Ø_C = sin^-1(1/n_p)

Question 296

If one were to increase the temperature of the air in the tube, how would that affect the fundamental resonant frequency observed in the tube?

Answer 296

• The speed of sound increases in hotter air
• The fundamental wavelength would stay the same, since the length of the tube is not changing
• Since f=v/λ and v increases and λ stays the same—
  
  • The fundamental resonant frequency in the tube would increase, since the speed of sound would increase in hotter air

Question 297

Based on the capped tube model of the ear, which of the following features would one expect to observe at 120001200012000 Hz if the equal-loudness chart was extended to that point?

Answer 297

• Capped tubes have multiple resonance frequencies.
• On the graph, a resonance is responsible for the minimum in the 1000-5000 Hz region on each of the equal-loudness curves
• The higher-order resonant frequencies are given by integer multiples of the fundamental frequency
  
  • Thus 4000×3Hz = 12000Hz should represent a resonant frequency for the tube
  • The capped tube model would predict an additional loudness-curve minimum at 12000 Hz.

Question 298

Which of the following expressions can be used to find the pH of a 0.15 M aqueous solution of sodium lactate at 25oostart superscript, o, end superscriptC?

Answer 298

Question 299

How will the equilibrium ratio of lactate to lactic acid ([C₃H₅O₃^-]/[HC₃H₅O₃]) be affected by post-mortem pH changes?

Answer 299

Question 300

What are the equivalent units for mOsmol/kg:

• mole per volume?
• mass per volume?
• equivalents per volume?

Answer 300

1. n: number of dissociable particles per molecule
   
   • Ex: NaCl —» n=2

Question 301

Before performing the titration represented by the graph in Figure 1, a chemist will add a drop of another weak acid that has a pKa of around 8. What is the likely reason for the addition of this weak acid?

Answer 301

Question 302

1. The speed of the water flowing out of the hole is given by which expression?
2. If while the water was flowing someone were to place an airtight cover over the top of the container, what would they likely see and why?
3. If the open top tank experiment were repeated, but a liquid of a larger density than water (but the same viscosity of water) were used, what would be seen to happen?
4. If someone were to take the tank off of the table while the water is flowing out, and drop the entire tank allowing it to free fall downwards, what would be seen to happen to the water flowing out of the hole?

Answer 302

1. √2gD
2. The water would at first flow the same but soon stop flowing out of the tank since the dropping water level would create a partial vacuum above the water in the tank
3. The density can be divided out of the equation:

• ρgh₁ + ½ ρv₁² = ρgh₂ + ½ρv₂²
• the density does not matter, which means it would flow at the same rate as the water.
• The weight is greater, but the inertia is also greater, and those effect cancel each other out.

1. Since the freely falling water does not exert any force on the water below it, it is effectively weightless and the water would not flow out of the hole

Question 303

What would be the correct ranking of the average kinetic energy of the gas molecules of the gases based on how they are labeled?

Answer 303

KE_Krypton​ > KE_Xenon > KE_Argon > KE_Helium

Question 304

Based on how the canisters are labeled, how would you rank the heat capacities of the gases at constant volume C_v?

Answer 304

C_{v Argon} > C_{v Helium} > C_{v Xenon} > C_{v Krypton}​

Question 305

1. Which area of the graph would be equal to the amount of work done to the system after systole?
2. From step 4 to step 1, no work is being done either to or by the system. What type of thermodynamic process would this be?

Answer 305

1. The area underneath curve 1-2 is representative of the work put into the system
2. Because volume is being held constant as pressure changes, the process from 4 to 1 is an isochoric process (also known as a constant-volume process, an isovolumetric process, or an isometric process)

Question 306

1. An ________ ___________ is a thermodynamic process that involves maintaining a constant entropy, that is, no heat is lost from the system during the process.
2. Would the cardiac cycle be considered a/an ________ ___________?

Answer 306

1. Adiabatic Process
2. No —» Energy will be lost as heat during muscle contraction due to the metabolic processes involved in fueling cardiac tissue.

Question 307

Charles’s law

Answer 307

• Volume —» metric units (i.e. cm³)
• Temperature —» Kelvin (K)

Question 308

How can an experimentally observed volume of < 20π cm³ at -15^oC be explained?

Answer 308

The gas condenses to liquid at a temperature slightly greater than -15°C.

Question 310

Answer 310

Question 311

What causes duplex DNA with a certain (A + T):(G + C) ratio to melt at a higher temperature than comparable length duplex DNA with a greater (A + T):(G + C) ratio?

Answer 311

Increased π- stacking strength

Question 312

where does reduction nd oxidatino occur at the anode and cathode?

Answer 312

“Red Cat” = REDuction occurs at the CAThode and “An Ox” = OXidation occurs at the Anode

Question 313

what type of bond is this

Answer 313

coordinate covalent

Question 314

Answer 314

Question 315

Answer 315

Question 316

64 - 20

74 - 40

Answer 316

D. 100

Question 317

focal length = -50cm

Answer 317

Solution: The correct answer is D.

This is a Physics question that falls under the content category “How light and sound interact with matter.” The answer to this question is D because the lenses have a negative focal length which means they are diverging lenses. Such lenses form virtual and reduced images of objects situated at distances larger than the focal length. It is a Knowledge of Scientific Concepts and Principles question because the question requires identifying the relationships among closely related concepts.