Chem/Phys Flashcards
There is 60% 4a and 40% 4b. What can be inferred from the results of Scheme A about the relative thermodynamic stabilities of Compounds 4a and 4b?
A.They are equally stable.
B.Compound 4a is less stable than Compound 4b.
C.Compound 4a is more stable than Compound 4b.
D.Nothing can be inferred about relative thermodynamic stabilities.
The answer to this question is C because there is a higher percentage of Compound 4a than Compound 4b at equilibrium (a thermodynamic mixture). For a thermodynamic mixture of isomeric products, the relative mole ratio of products is directly related to the relative stability of these products.
Capacitor formula and units
Q=CV
Capacitance is in F (farhads)
Q charge is in C (coulombs)
Voltage is in volts
Suppose that the railcar passes by a horn that is emitting a sound with frequency f. Which of the following describes the frequency f PS-10-1-prime.gif that the person on the railcar hears?
A. f PS-10-1-prime.gif > f before passing the horn, f PS-10-1-prime.gif < f after passing it
B. f PS-10-1-prime.gif < f before passing the horn, f PS-10-1-prime.gif > f after passing it
C. f PS-10-1-prime.gif = f before passing the horn, f PS-10-1-prime.gif = f after passing it
D. f PS-10-1-prime.gif > f before passing the horn, f PS-10-1-prime.gif > f after passing it
The answer to this question is A because, due to the Doppler effect, the frequency that the person on the railcar hears before passing the horn is larger than the actual frequency of the sound emitted, while the person hears a frequency lower than the actual frequency after passing the horn.
Power formulas and units
P=W/t
P=F*v
Power units: kg⋅m2⋅s−3
Work: Joules
Force: Newtons
The relative thermodynamic stability of isomeric organic compounds can be inferred from which of the following types of experimental data?
A.Boiling points
B.UV–visible absorption spectra
C.Mass spectroscopic fragmentation patterns
D.Heats of combustion
The answer to this question is D because the relative thermodynamic stability of isomers can be determined based on the amount of heat produced when the compounds are combusted; less heat, greater stability.
The energy of activation for the reaction described in the passage is given by the energy of:
A.the reactants minus the energy of the products.
B.the products minus the energy of the reactants.
C.the activated complex minus the energy of the products.
D.the activated complex minus the energy of the reactants.
The answer to this question is D because the activation energy for a reaction represents the minimum energy barrier necessary to be overcome by the reactants on the path to products.
REVIEW THESE TERMS .a transferase. B.an isomerase. C.an oxidoreductase. D.a hydrolase.
Learn these
What is the structure of a steroid hormone?
Four fused rings
Mass of an amino acid
135 Dalton or AMU
KNOW THESE
D/L
S/R
Learn these
What is the concentration of hydroxide ion for the solutions with pH 10?
A.10–10
B.10–6
C.10– 4
D.10–2
The answer to this question is C because, at the highest pH tested (10) the [H3O+] is 10–10 M. This means that [OH–] is 10–4 M, because [H3O+] × [OH–] = 10–14 for aqueous solutions at 25°C.
Energy of a photon formula
E = hf
f=c/λ
c is m/s so like velocity or wave speed
The isoelectric focusing points pI for four proteins are shown in the following table.
Protein pI A 8.8 B 10.2 C 4.3 D 5.5 At which buffer pH would two out of four of the proteins adhere to a cation-exchange column?
A.3.0
B.7.0
C.9.5
D.11
The answer to this question is B because a cation-exchange column only binds to positively charged proteins, which only occurs when the pH is less than the pI. At pH 7.0, both proteins A and B would be positively charged. With distractors A, C, and D, there would be four, one, and zero positively charged proteins, respectively.
Pressure formula and units
P=F/A
P=densitygravityheight
Pressure (pascals)
