Altius FL 1 Test Chem/Phys Review

Question 1

Q1

Answer 1

The key in the question is that they wanted an answer that will give the MOST EFFECTIVE OF all the options and would detect the PRESENCE and NOT ABSENCE of the deuterated products. It is important to note that deuterated products are similar to hydrogenated profucts except that the deuterium has an atomic weight that is higher than hydrogen which is a key in the passage for the answer. The correct answer will attend to that difference. Gas chromatography is wrong because it deals with boiling point differences in liquids with a mobile gas phase. UV spectroscopy is looking at conjugation differences which will be rooted in the electron and proton profile but these are equal in both cases. 1H NMR Spectroscopy could be answer because it will detect only the hydrogenated compounds and not the deuterated compound. Also, it is wrong because the question asks for one that will detect the presence but not the ABSENCE. Additionally, the clue in the 1st paragraph ending shows that the improved performance is as a result of the increased atomic weight.

Question 2

Q2

Answer 2

Correct. It could not be charge because their atomic number is equal so A and C are out. It could not be D because due to their atomic number (proton, electrons, and lone pairs), they would still have the same molecular geometry. The answer had to be B.

Question 3

Q3

Answer 3

Correct. It could not be A or B because both describe absorption, in which light energy is absorbed and the result is the excitation of electron to a higher energy level. It could not be C because emission is when light energy releases photon energy and NOT positron energy. The key to this answer is also in the 1st paragraph where the background and mechanical process of OLED is summarized.

Question 4

Q4

Answer 4

Correct. The key to this question was recognizing that after looking at Pb in the question, what is the characteristic of higher zero-point energy between two atoms. The key is in the second paragraph where they say that heavier isotopes have a lower zero point energy. As such, the answer should be a lighter isotope that will have a higher zero-point energy. To answer this question, it is important to know what the criterion is to have a higher-zero-point energy. This can be achieved by keeping the atomic number constant and looking at the changing mass number.

Question 5

Q5

Answer 5

Correct. The answer is a restatement of the Hendersen Hasselbach equation. It is important to note which particular ratio they are looking for. Is it Base to Acid or Acid to Base. This is a subtlety in the question. I got this because I paid attention that that discrepancy and noted it.

Question 6

Q6

Answer 6

Correct. For me, it was a restatement of Le Chatelier’s principle. The stepwise thing in this question is asking (from the options): what is the effect of the breakdown of fatty acids (well it releases H+)? This leads to an increase in H+ concentration, hence a lower pH and acidic environment. Le Chatelier’s principle states that the body counteracts this to return to equilibrium by shifting to the left (in the case of equation 2) in order to decrease the production of H+ ions.

Question 7

Q7:

Answer 7

I got this correctly but my clue was in the options. In the future, I need to know what exactly hyperventilation is, what is the effect of hyperventilation? Why does it occur? in addition, I also need to be aware of the definition of other related concepts like hypoventilation, etc. This is a content review question.

Question 8

8. Pearl divers in Japan are able to dive for long periods of time, without breathing, to harvest pearls. Is it reasonable to conclude that the blood pH of these divers would decrease near the end of a dive?

Answer 8

I got this correctly because I learnt how to eliminate answers from the options but in the future with a confusing option, I could have got it by paying attention to the question. The question gives a clue “without breathing”. That means that there will be little exchange of gases (oxygen and CO2) when they are underwater and throughout that journey. With that in mind, there will be a decrease in oxygen and an accumulation of CO2. Le Chatelier’ principle can be applied to note that there will be an equilibrium push to the right because of an accumulation of CO2 and thus leading to increased H+ and therefore acidosis.

Question 9

9. H3PO4, the molecule primarily responsible for the maintenance of pH in the cytosol, contains three acidic protons. Which equilibrium constant is associated with cytosolic buffering by H3PO4?

Answer 9

This I got wrong but the going forward, I need to review solubility, acids, bases, titrations, and more. The trick here is that you should know the three dissociation profiles of the acid in mind. After you are aware of that, you have to know which profile is dominant in which pH region based off of the graph. The key here in the question is that the answer is cytosolic (pH ~7). With that in mind, the answer will be in the profile that corresponds to this specific pH and that is why my answer was wrong and theirs was the correct one.

Question 10

11.) Which change in solution composition would cause a protein to elute from a hydrophobic interaction column?

Answer 10

I got this correctly by making an educated guess. The answer here is recognizing what a hydrophobic interaction column is and how it achieves its process and then using this knowledge to answer the question. The logic of this question now is very interesting and I need to review all chromatography columns now. The proteins have various interactions but the reason why is adheres to the column is because all its interactions are being accounted for. The hydrophobic regions are staying put because their hydrophilic regions are also staying put. So to reduce it, you have to reduce the solution region, hence decrease the salt concentration. If the question had asked what change we want in the column, then the answer would be to increase salt concentration. A and B would be correct if in A, the column was acidic and we were making it basic or if the solution was basic and we were making it acidic. This logic can be used in determining answer B.

Question 11

12.) Students added HCl dropwise to a solution of phospholipids with an initial pH of 7.4. Upon reaching a pH of 4.0, what changes will have occurred to the [COO-] and [COOH] present on the phospholipid head?

Answer 11

Wrong. The answer here was B and the logic in one case is to realize that acid form and basic form cannot increase simultaneously. One has to increase while the other decreases. Hence C and D are automatically wrong. When you think of acid solubility, acid dissociates and causes water to have a proton added to it. The water can now donate the proton and with this logic, it will donate it to the organic acid and thus lead to the protonated form. It is important to note that if the option had “decreased COO-“, it will still be wrong because that’s not the mechanism. the mechanism is because water has an increased concentration of H+ and the anion is pulling it and becoming protonated in the process.

Question 12

When illuminated, the solar cell is analogous to a battery. In this context, which portion of the solar cell acts as the positive terminal?

Answer 12

The logic they want you to use here is to understand circuit flow elements. Electrons flow from the negative to the positive terminal and current flows from the positive to the negative terminal. And terminals are limited to electrods and nothing else. There is still a need to understand voltaic cells, electrolytic cells, and what batteries are considered.

Question 13

14.) If the solar cell is illuminated by monochromatic light in the visible spectrum, which color would produce the most electrical energy per photon?

Answer 13

The question stem is asking you which will be the most efficient. The key to this answer is to recognize the graph shown in the passage which has to do with efficiency. Red and violet can be ruled out because based off the graph, they are at the extremes and as such they will be the least plausible answer. Ultraviolet is wrong because it asked for an answer in the visible spectrum but UV light is out of it. It had to be GREEN after elimination but most importantly after looking at the graph. RECOGNIZE definitions!

Question 14

15.) The two parallel plate electrodes give the solar cell an inherent capacitance. If the distance between the plates in Figure 1 were increased from 20 µm to 40 µm, the capacitance would:

Answer 14

Formula for capacitance is the key.

Question 15

16.) Figure 3 compares solar cell efficiency for light of various wavelengths. For four wavelengths, 400 nm, 525 nm, 700 nm, and 820 nm, which wavelength contains photons with the most energy?

Answer 15

There is a difference between most energy per photon and photons with the most energy.
- Knowledge of the formula is required E = hf or the other forms with wavelength

Question 16

18.) If the in vitro GC analysis were conducted at a reduced temperature, how would the spectrum obtained differ from Figure 1?

Answer 16

• Effect of temperature on GC. Higher will make it quicker but will not affect the inherent polarity.
• Lower will make it slower and will increase peaks since some would not be overlooked.

Question 17

19.) What do the mass spectral fragmentation data for the muconaldehyde isomers reveal about the relative stability of geometric isomers? Under electron impact ionization:

Answer 17

Mass spec science needs to be learnt. It tells you the fragment, its abundance, its stabilitiy based on the abundance and the atomic weight (mass/charge ratio).
- No information on the cleavage and boiling point.

Question 18

21.) One theoretical model of enzyme-substrate interaction explains enzyme catalysis as a function of the stabilization of the transition state by the enzyme active site. This is an example of the:

Answer 18

• Distractors were catalysis and Michaelis-Menten mechanism.
• Lock and key as it implies but too much energy to release following function
• Induced fit makes up for this by stabilizing the transition state and able to dissociate following interaction.

Question 19

23.)

What is the most likely result of a mutation in chymotrypsin from Asp-102 to Glu-102?

Answer 19

• Mutations are detrimental most times, hence there has to be some effect.
• It couldn’t be large because the inital stuff was the optimal and hence digression begins to decrease it.
• There has to be a change. Do not confuse for SILENT MUTATION! This is not the case.
• For the science and concept, see how a larger size can affect the active site or a smaller size. Go down to the basic level.

Question 20

26.) The magnetic field in an MRI machine is created by a current in a solenoidal (spiral-shaped) wire. The magnetic field in a solenoid is given by the equation below, where n is the number of turns per unit length, I is current, and µ0 is a constant. If the strength of the field at the center of the solenoid is known, what additional information is needed to determine the current carried in the wire?

Answer 20

• Constant typically will not affect the solution of something. the unknown is more critical
• Use the formula to answer.

Question 21

30.) The slope of a Hill plot is used to quantify enzyme cooperativity. Given the graph below, what is the Hill coefficient for GCK?

Answer 21

• Hill plot mechanism
• Hill coefficient = slope
• Slope > 1 (rise over run) positive is cooperative

Question 22

31) Which biomolecule is most likely to compete with glucose for binding at the GCK active site?

Answer 22

• Recognize that enzyme is involved so it is competing with somethign that can enter its active site.
• Think of a similar shape and structure.
• Learn structure of Acetyl-coA, linoleic acid, sucrose
• Sucrose could have been the answer if mannose was not there because it is the same size and just an epimer but sucrose has two sugars joined.

Question 23

32.) For an enzyme such as GCK, which exhibits positive cooperativity, each successive ligand will:

Answer 23

• What are positive, negative, and no cooperativity?
• Graphs
• What do they mean according to the enzyme and the graphs?
• Positive cooperativity, relates to association and dissociation, is that when you bind of one thing, the binding to the other subunit will be faster and stronger than the previous one.
• Negative cooperativity, relates to association and dissociation, is when you bind to one thing, the binding to the other subunit is slower.
• No cooperativity is when binding is simultaneous in all sites and at once (I think)

Question 24

33.) Which conclusion about normal GCK allostery is most consistent with the data in the passage?

Answer 24

• Use both the stated data and the figure plus statistics to answer the question.
• A, C, and D are contradicted in both the passage and the data or figure.
• C is based off the proposed theory of number 2 and which it follows.

Question 25

34.) For how many hours after startup did the system convert 100% of the Cr(VI) to Cr(III)?

Answer 25

• Tutor says that the focus is P3. I am confused but it will make sense because that is what is transferred to the clarifier.
• It is saying when will 25 mg/L of the starting Cr(VI) become or yield the exact 25 mg/L of Cr(III).
• In order words, when will one be 0 and the other will be 25

Question 26

35.) If the apparatus in Figure 1 is operating optimally, which two precipitates should be present at the clarifier?

Answer 26

• The trick here is to recognize that the clarifier is where the products of the reaction will be as stated in the second paragraph.
• The equation gives you clue on the hydroxides
• This guide will help determine the identity of the hydroxide metals and thus the answer.

Question 27

37.) During the first 48 hours, the pH of the reaction mixture is sampled as it passes from P1 to P3. Which pattern is expected?

Answer 27

• The equation shows that H+ is the reactant side so that means it is being reduced or consumed.
• The paragraph 3 states that it starts off basic and so the pattern from the description will be steadily increasing pH since acid is decreasing.
• It could not be pH 7 because of the metal hydroxide. Its addition is vital in the inference.

Question 28

38.) Based on reactions 1 and 2, researchers interested in increasing the efficiency of the chromium(VI) removal process should add which compound to the untreated water?

Answer 28

• THink of what makes the reaction occur based off of the reactants using the equation.
• Le Chatelier’s principle can be applied.
• Think of increasing the products, i.e. increasing Cr(III) and reducing Cr(VI)

Question 29

42.) Experimental data suggest NS1-2 exists as a dimer. Which size-exclusion chromatography spectra is consistent with an NS1-2 mixture which may contain a folded monomer, an unfolded monomer, or a folded dimer?

Answer 29

• Key: Size exclusion chromatography, its principles, and graphs
• First elution is the larger one and the second elution is the smaller one.

Question 30

Q43

Answer 30

1. Not that in an uncombined state (solid, liquid, gas), the oxidation state is zero

Question 31

46.)

Answer 31

• PV = nRT
• Realize that final can ignore initial
• R can be approximated as 0.08
• T is in Kelvin
• Do not forget that the final is the sum of the initial and the calculated pressure

Question 32

47.) For the experiment described in the passage, which graph depicts frequency shift as a function of the wavelength of the laser?

Answer 32

• The graph is as a result of understanding the formula that relates frequency to wavelength, and then speed of light

Question 33

49) The lens shown in Figure 1 creates an image of the rotating and static diffusers on the sensor. If the focal length of the lens is 25 mm, the image formed at the sensor will be:

Answer 33

• Recognize the sensor is the image
• Distance is the object
• Review the formation of images at mirrors and lenses

Question 34

50.)

Answer 34

• Flow of liquid (moving fluids) is bernoulli’s equation. Narowing is Bernoulli’s
• Velocity and Pressure is Bernoulli’s equation
• Flow rate involved.

Question 35

52.) In Reaction 2, iodine is titrated with thiosulfate. What color change signals the endpoint?

Answer 35

• Understand the ordering sequence

Question 36

53.) Suppose researchers need a purified sample of ᴅ-limonene with minimal contamination. To accomplish this, ᴅ-limonene could be doubly distilled:

Answer 36

• Goal is to exclude oxygen and the best way to do and ensure that is using something that completely excludes oxygen which is nitrogen.

Question 37

54.) The autoxidation of ᴅ-limonene in the presence of O2 results in a mixture of products. Which structure is LEAST likely to be detected as an oxidation product of D-limonene?

Answer 37

• Trick here is ensure that only O is being added

- Addition of another atom changes it from being oxidation to Carboxylation in this case.

Question 38

55.) The ᴅ designation in ᴅ-limonene is an abbreviation for dextrorotatory. This indicates that ᴅ-limonene rotates polarized light:

Answer 38

• D - Rotates clockwise to the right

- L - rotates counterclockwise to the left

Question 39

59.) Which of the compounds shown will produce exactly two peaks in a 1H NMR spectra?

Answer 39

• Trick here is noting that 1H NMR spectra peak is for the tyoes of hydrogen and not the splitting