Q8: We can see that a "spike" occurs in the graph, and that takes place over a time of 1 millisecond (1 msec). This suggests that the probe has a resolution of 1 ms or 10^-3 s. Specifically, the event occurs when the SPIKE occurs in the graph.
If the pulse travels at 100 m/s or 10² m, then the closest distance we can place the electrodes can be found from
speed = distance / time
distancce = speed * time
distance = (10² m/s) * (10^-3 s) = 10^-1 m = 0.1 m
Therefore, B is the best answer.
Q16: Yes. Very good! Only one part of the di- or poly-saccharide needs to interconvert to the open-chain form for the sugar to be considered a reducing sugar.
Q27: Yes, the Doppler effect is the primary mechanism by which this test works because the test is trying to show the MOTION of the fetus. This is called Doppler ultrasound.
Based on the formula for the Doppler effect:
fobserved = fsource * (v +- vo)/(v -+ vs)
We need to have ONE UNKNOWN.
The best answer is B because it leaves us with one unknown. C is not a good answer because it leaves us with zero unknowns.
Q28: Yes, hydrogen bonding can only occur with FON atoms as you say. So H-bonding will occur between HF to a much greater degree (actually... AT ALL) than it would if we had H-Cl or H-Br because Cl and Br aren't one of the FON atoms. C is the best answer. D doesn't answer the question as well as C does.
Q32: We're used to seeing Ka mean acid dissociation constant, but in this passage, it doesn't mean that.
First (as defined in the passage) K0 is the affinity of CPFX to bind with BSA. Then, Ka is the affinity of (either) warfarin or ibuprofen to find with BSA.
We are told in the passage (above Table 1) that warfarin likes to bind to site I and ibuprofen likes to bind to site II.
Since Ka/K0 is 0.46 for warfarin, this suggests that there is a competition for binding to Site I when BOTH warfarin and CPFX are added together. In other words: 46% of the time, warfarin will bind to Site I, while 54% of the time, CPFX will bind to Site I.
We don't see as strong of a competition for Site II, because the Ka/K0 value is 0.87. In other words, 87% of the time, ibuprofen binds to Site II, and ONLY 13% of the time, CPFX binds to Site II.
Therefore, Site I is the preferential bonding location for CPFX, and C is the best answer.
Q38: This is a very very heavy OChem question. I've found a fully-drawn out mechanism for you:
https://i.imgur.com/1CTl7Ke.jpeg
The major thing that I noticed was that none of the marked carbons are on a CARBONYL carbon. This really helped me track them through the mechanism.
Q39: It's fine that this is a carboxylate anion. Technically it exists in resonance with the other carbonyl group, so it is relatively stable with the excess negative charge.
I'm not sure which question you're referring to with regards to NH.