How do you distinguish the basicity levels for amines? Like what makes an amine a weaker/stronger base? And why? (The more the lone electron pair of N is involved in conjugation, the less basic it is. Also, sp2-hybridized nitrogen is less basic than sp3-hybridized nitrogen, because the lone pair has lower energy and, therefore, less reactive. - GS).

Weak base = better leaving group for sn1 and sn2? (Yes. Also for E1 and E2 - GS).

Does protonation create a better leaving group? (Yes for alcohols. - GS).

Resonance structures provide a means to show electron delocalization which in turn stabilizes the structure, right? (Yes. - GS). So for simplicity’s sake this means that structures that can be demonstrated using resonance structures for it are more stable than a similar molecule that cant form resonance, right? (Correct. - GS).

^^Could you explain why electron delocalization would be seen as stabilizing if a carbocation or anion would constantly result from this formation? (Electrons will have more space and more opportunities to lower their energy. Same on the math language: there will be more coefficients to optimize in the linear combination of atomic orbitals - GS). Wouldn't a neutral structure with no charged carbons be more stable than one that would observe resonance characteristics?  (The neutral structure will be most contributing. - GS).

How do you know which reaction product is less stable? For example, in the addition of HCl to conjugated dienes, the major product formed is 1,2-addition results in major product which is less stable than 1,4-addition. Is 1,4- just typically more stable? (Yes, because of a more substituted C=C bond - GS).

How do you determine the rate limiting step in a reaction that consists of multiple steps (with no fore knowledge (It is impossible. That what that knowledge is for. - GS). of rate speeds/ no diagram)? Is it simply the first step? (No. It is the step with the lowest activation energy. - GS).

What makes CH3 an electron donor when it is bonded to benzene? (sigma-pi conjugation. - GS).

^^ can you please explain how to tell when a sigma and pi orbital overlap? (When they are at carbons next to one another and are aligned - GS).

Is dehydration considered an elimination reaction? (Yes for alcohols. - GS).

When determining ortho-para or meta directors, do you look at the substituent that is already attached to the ring (Yes. - GS). or at the substituent being added? (No. - GS).

Can a benzyl group technically also be considered as a phenyl group? (I know that a phenyl expands from just a benzyl but was wondering if it was correct to think that a benzyl could potentially be a phenyl as well? Thanks (No. They are different groups. - GS).

Can catechol also be called ortho-hydroxyphenol? resorcinol = meta? and hydroquione = para? (Yes. - GS).

Do both E1 and SN1 reactions proceed through a carbocation? (Yes. - GS).

What’s the difference between an epimer and a diastereomer? I have written in my notes that configuration of only one center is opposite for both of them. Thanks. (Epimers are different by the configuration of one chiral center. They can be diastereomers. - GS).

Generally speaking, if an atom has high nucleophilicity, does that make it a bad leaving group? (No. High basicity does. - GS).

So, great leaving groups would be those that are weak bases correct? (Yes. - GS). That strong acids would be the best leaving groups (once they are deprotonated?) (No. Conjugate bases of strong acids are good leaving groups. - GS).

Can you explain the properties and reactivity of antioxidants? (They intercept reactive free radicals. - GS).

Does elimination always form a double bond? (No. E1 - yes. E2- either double or triple bond. - GS).

are electron donors always ortho-para, because they are more stable due to resonance structures? (Donors always preferentially stabilize intermediates leading to products of ortho- and para- substitution. - GS).

What is the difference between CH3 and alkyl? (Methyl is an example of alkyl - GS).

Are halogens inductive acceptors and resonance donors? (Yes, but Cl, Br, and I are also resonance acceptors because of the empty d-orbitals - GS). So, are halogens resonance donors and resonance acceptors? (No. They are resonance donors and inductive acceptors. Cl, Br, and I are also resonance acceptors because of the empty d-orbitals - GS).

How many steps does the electrophilic substitution (SeAr) have? (Three. - GS). What are the names of 1st and 3rd steps? Is third dehydrogenation of the pi complex? (Step 1- pi-complex; Step 2 - sigma-complex (rate limiting); Step 3 - deprotonation. - GS).

What directs the position of substituents? The substituent on the benzene ring prior to the reaction? Or the electrophiles? (The existing substituent before substitution. - GS).

Would you mind explaining why ethanol for gasoline is so effective at functioning as a “fuel”? (Ethanol increases resistance of fuel to premature ignition (increases octane rating) by intercepting free radicals, but decreases the energy content of fuel (mileage) - GS).

Could you explain how DDT work as pesticides? (By opening sodium channels and, therefore, disrupting nerve impulses. - GS).

Why would a compound that mimics a plant growth hormone be used as a commercial lawn fertilizer?  Wouldn't that just cause the plant to grow more quickly? (Yes, it is not a nutrient. In larger concentrations, they are used as herbicides, because they make the plant grow so unnaturally fast, that the plant dies quickly. - GS).

Brominated organic molecules are used commercially as flame retardants, why is that? (I thinks that the three following contributors are important: 1. Br-containing molecules act as traps for free radicals, so they speed up free radical chain termination; 2. Non-combustible molecules (HBr and Br2) are produced, and they extinguish fire like carbon dioxide; 3. Bromine does not bond well with oxygen, so the energy spend on breakage of the C-Br and C-H is not compensated enough by a relatively weak H-Br bond. - GS).

The flammability is due to its ability to oxidize in addition to its high energy, right? so what makes a molecule more capable of oxidizing?  (This is a good factor, but it is also important how well the compound mixes with oxygen, and how well a free-radical chain reaction sustains. - GS).

Why doesn’t free radical halogenation with iodine occur ? (The H-I bond is too weak to make up for the broken C-H bond. - GS). Why is free radical halogenation violent when it occurs with fluorine? (The H-F bond is very strong and releases energy that rips apart the molecule. - GS).

Alcohols are a weak acid, which is why we can intake alcohol without experiencing severe irritation, right? (Ethanol causes irritation when its concentration exceeds 40%, which corresponds to the hydrate of ethanol. Above this concentration, ethanol acts as a drying agent. It was a part of M.S. thesis of Dmitri Mendeleev, which is much less known than his periodic table of elements.  - GS). But just out of curiosity is the fact that alcohol is indeed a acid (even though its weak) one of the reasons alcoholics experience extreme symptoms such as ulcers (which could be described as an erosion or “break” of intestinal lining, etc.)? Is that alright to observe those effects in that manner, or is that side effect due to a different characteristic altogether? (No. Those adverse reactions are mostly because of oxidation of ethanol to a toxic ethanal. - GS).

So is it wrong to think that more polar molecules often have lower boiling points if the molecular size is similar? (Polar molecules have higher boiling points because of stronger electrostatic intermolecular interaction. - GS).  Larger molecules have higher boiling points? (Yes, because of stronger Van-der-Waals intermolecular interaction. - GS).

Could you go over how the free radicals one more time? I still don’t fully understand it. Thanks (Ok. Please, also review this: http://ochem.orgfree.com/SR.html  - GS).

Hi Dr. Sereda, I was wondering if you could explain a little better the relationships with the boiling points, polarity, molecular size, and molecular shape? (Molecular shape determines polarity. Polarity and molecular size, and again shape, determine intermolecular interactions. Intermolecular interactions determine the boiling points. - GS).

Is a rearrangement reaction going to take place when the conditions are in line with a SN1 reaction? Because a rearrangement reaction is where a carbocation gets reformed into something more stable and in an SN1 reaction is where one of the steps to get to the product is through a carbocation intermediate. (Yes. SN1 and any other reaction involving carbocations can be complicated by carbocation rearrangements. - GS).

Dr. Sereda would you mind explaining how we differentiate between SN1 (http://ochem.orgfree.com/sn1.html  - GS) and SN2 (http://ochem.orgfree.com/sn2.html  - GS). reactions? (See the links that I inserted to your question. - GS).

There is not a big difference between E1 and Sn1 reactions, as it is in E2 and Sn2? If there is one, could you explain? (Elimination requires a base and produces a C=C bond, substitution requires a nucleophile and does not produce a C=C bond. - GS).

Dr. Sereda, could you please remind me how I find E2 reactivity when working with halides? Thank you (A better leaving group, stronger base, and the most substituted C=C in the product will increase E2 reactivity. - GS).

If you double both concentrations of the reactants in an SN2 reaction, does that mean that the reaction rate will increase by 4? (Yes, which proves that it is a second order reaction (22=4). - GS).

Would a hydrogen be most readily substituted with a Br from a carbon that has the least number of H (according to Zaitsev’s rule)? (Yes, but not because of Zaiysev’s rule. That will be free-radical bromination. - GS).

What kind of effect does an Sn2 reaction have on the product? (If this reaction occurs at a chiral center, its configuration flips. - GS).

Is a glycol still considered an alcohol? (Yes. - GS).

Are fischer projections strictly for chiral carbons/centers? (No. They are for looking across any chemical bond in an eclipsed conformation from behind. - GS).

Different compounds can be expressed in terms of optically pure compounds as (+) or (-), could you explain how we are supposed to differentiate between when its (+) or negative? Is it simply in regards to the rotation it expresses so it has a negative then it would be because it is the enantiomer of the optical compound? (If a compound has positive rotation, its enantiomer will be for sure negative, and vice versa. You cannot determine an absolute value or sign of rotation just by the structure. An experiment is needed. - GS).

^^Sorry this may be naive, but what do we gain by knowing if its (+) and (-)? (It is part of a compound’s identity and purity, like its melting point. - GS).

^So you could use it as another way to identify a compound? (Yes, and evaluate its purity, which also embraces monitoring chemical reactions of that compound. Mutarotation is a great example. - GS).

Newman projections are only for alkanes, right? (No. They are for looking along any chemical bond. - GS).

how does a racemate relate to a meso compound? I am confused where this would fit into their nice flowchart that they have given to us in the text. (Racemate is a mixture, meso-compound is one compound. Components of a racemic mixture are enantiomers. - GS).

I am not fully understanding the idea of the meso compounds. I read the book and have an idea, but I was wondering if you could go over that again in class in better detail? thanks! (Meso-compounds are achiral compounds with chiral centers. - GS).

I dont understand how a molecule can be a mirror image but not be congruent? IS there any way you could draw an example of this, if it is even possible? Thanks (Your hands or feet are excellent examples of such objects. - GS).

Is an asymmetric carbon and a chiral carbon the same thing? (Yes. - GS).

^^or an asymmetric carbon and a chiral center? (No. Not only carbons can be chiral centers. - GS).

Why does a book describe a hand as being chiral? I get why its an enantiomer but why chiral? (Because it is different from its mirror image. - GS).

If a 2 compounds are congruent does that make them identical? (Yes. That is another word for this. - GS).

How do you determine how many chiral centers there are??? (Pick atoms with 4 different substituents, and count them. - GS).

why is the sigma bond in a double bond sp^2-sp^2, and the triple bond sp-sp? (Because in the first case, geometry at carbon is trigonal planar, and in the second case - linear. - GS).