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In a thermodynamic mixture of isometric products….. |
the relative mole ratio of products is directly related to the relative stbailiyt of these products. |
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Aldol condensation |
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Which type of product will form if the aldol condensation is not followed by a dehydration reaction? |
b-hydroxycarbonyl – aldol |
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If no braking occurs, a total of how much would be required to keep railcar moving at 40 m/s? Decelerating force = 5000N |
The power required must match the work done by the friction force that tends to slow down the railcar: P = (decelerating force – friction) x (speed) 1000N x 40m/s = 40kW |
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If the generator-brake system alone were engaged when the railcar was moving, what type of graph would accurately represent the speed of a decelerating rail car? |
The speed of the car decreases in time such that the deceleraitng force declines linearly with speed according to the passage. Becuase the decelerating force is proportional to the deacceleration, it follows that the decelerating acceleration itself declines linearly with speed. Because acceleration decreases linearly, the velocity of the car will decrease in the shape of a parabola. Finally, because the decelerating acceleration is a rate change of velocity or the slow of the velocity vs. time graph, the slow of the graph must decrease in time. |
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The relative thermodynamic stability of isomeric organic compounds can be inferred from which of the following types of experimental data? A. BP B. UV-absorption spectra C. Mass spectroscopic fragmentation patterns D. Heats of combustion |
D The relative thermodynamic stability isomers can be determined based on the amount of heat produced when the compounds are combusted; less heat, greater stability Boiling points = indicative of Intermolecular Forces. Combustion = Intramolecular covalent bonds (between atoms of a molecule), and when it combust you are breaking those bonds. |
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Consider the following: Susbtance Ka Kw/Ka Based on these data, HCO3- is best categorized as: |
base since Kb > Ka for this ion The Ka for HCO3- is 5.6E-11, while the Kb is 2.3E-8. Comparing Ka to Kb, Kb is much larger than Ka thus, HCO3- is more basic than acidic in water |
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Frequency and period |
The period is the time between consecutive intervals. |
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scientific notation |
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The glucose meter measures the current produced during reaction 3. If 0.67 micromol of electron were measured, what mass fo glucose was present the sample? MM glucose is 180g/mol, reaction 3 produces 2 electrons per glucose molecule |
60microgram The device measured .67 (2/3) micromol of electrons, indicating that 0.33 (1/3) micromol of glucose was consumed. 0.33 x 180 = 59.4microgram |
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What additional substrate is necessary to convert D-glucose (-OH) to D-glucuronolactone (-COO)? A. NADH B. FAD C. H2O D. Acetyl-CoA |
B The reaction requires an oxidizing agent for this reaction to proceed. Of the listed options, FAD is the only cofactor oxidant |
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Steroid structure |
Characterized by 4 fused ring structures |
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The pH of 1L phosphate differ solution was measured as 7.6, but the experimental procedure calls for pH 7.2 buffer. which method will adjust the solution to the proper pH? (The pKa values for phosphoric acid are 2.2, 7.2 and 12.3) A. Add enough 1M Na2HPO3 to increase the phosphate anion concentration ten-fold. B. Add 1M NaOH to neutralize a portion of the hydronium ion found in the solution C. Alter the ratio fo monosodium/disodium phosphate added to favor the monosodium species D. Add 100mL distilled, deionized water to dilute the basicity of the buffer. |
C To lower the pH of the buffer, the proportion of acidic buffer component must be increased. Adding strong base, diluting with water, or adding a different basic salt will not lower the pH pKa is the pH at which we get 50% protonated and 50% unprotonated species. The pkA of 7.2 corresponds to H2PO4- —> HPO42- + H+. Therefore, if we want to decrease the pH we need to make more H+, how do we make more H+, add more monosodium phosphate which based off Le’Chatelier will dissociate to create more H+. – Disodium must have a -2 charge (to balance the 2 Na+) – Monosodium has a -1 charge. Since we are given that phosphoric acid has 3 pKas you could reason that the 3 forms must be H3PO4 (no charge no sodium) H2PO4 -1 (-1 charge so monosodium) HPO4 -2 (-2 charge so disodium A. Na2HPO3 had a pka that is too high (12.3) , it will increase pH if added B. NaOH is a strong base and will increase pH C. Monisodium species has a pka of 7.2, which is the pH you want. Also it’s not as specific about the exact ratio. Adjusting the ratio this way will lower pH. D. Diluting with 100mL does lower the pH, but only to ~7.55 by my calculations. Diluting an acid/base is a poor way to reduce pKa. |
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Which experimental condition is NOT necessary to achieve reliable data for Michaelis-Menten enzyme kinetics? A. Initial velocity is measured under instead state B. Solution pH remians constant at all susbtrate concentrations C. The concentration of enzyme is lower than that of substrate D. The reaction is allowed dot reach equilibrium before measurements are taken |
D Once the reaction has reached equilibrium, the measurement of Vo will be impossible and the kinetic data will look the same regardless of the substrate concentration. Distractors A-C are essential to obstain reliable Vo vs. [substrate] data to calculate Km and Vmax using Michaelis-Menten enzyme kinematics |
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"Pasasge states Hydroxamic acid is made from acetylation (attachment of RC=O) of the hydroxylamine nitrogen (NHOH) in compound 2" What is the general structure of Hydroxamic acid? |
ACEYTL GROUP: CH3C=OR |
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Trimethyllysine |
Has three methyl groups on it’s nitrogen thus is not basic or hydrophillic |
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Ring substituent |
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which atom is most likely involved in the coordination of calcium ions in HRP? A. H B. N C. O D. C |
C The atom must be a Lewis base to coordination to calcium ions, and the oxygen is the only Lewis basic atom resent in the side chain or backbones of the listed AA that has either a particularly negative charge in the peptide backbone or Ser side chain) or a negative charge (in Asp). The only other Lewis basic atom present is nitrogen which has a partially positive chain in the peptide backbone due to resonance and is thus less likely to coordinate calcium ions. |
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Porphyrin |
aka Heme. The basic unit of porphyrin is the pyrrole ring, a five-sided heterocycle containing one nitrogen atom. |
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Resistivity |
inverse of conductivity |
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A common column material used in size-exclusion chromatography is dextran, a polysaccharide of glucose. Which type of interaction most likely occurs between proteins and the dextran column material? A. Aromatic B. Hydrophobic C. Salt bridge D. Hydrogen bonding |
D Since glucose has numerous hydroxyl groups that can H bond to the polar side chains that are typically exposed on a protein surface Size-exclusion chromatography (SEC), also known as molecular sieve chromatography, is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers. Large molecules elute first, then small |
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Scientific notation abbreviation |
1 000 000 000 000 tera (T) 1012 1 000 000 000 giga (G) 109 1 000 000 mega (M) 106 1 000 kilo (k) 103 0.001 milli (m) 10-3 0.000 001 micro (µ) 10-6 0.000 000 001 nano (n) 10-9 0.000 000 000 001 pico (p) 10-12 |
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Octahedral bonding |
Ex. SF6 |
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Forms covalent Network at Standard state |
Boron (B) Boron nitride (BN) Diamond (C) Quartz (SiO2) Rhenium diboride (ReB2) Silicon carbide (moissanite,carborundum, SiC) Silicon (Si) Germanium (Ge) Aluminium nitride (AlN) |
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