Hi Dr. Sereda I was curious how does the boiling behavior of a pure liquid differ from that of a solution? Thanks!! (Both cases obey the same rule - they start to boil when the total vapor pressure becomes equal atmospheric pressure. However, as opposed to a pure liquid, for a mixture, compositions of the vapor and the liquid are different, so as you are distilling out some vapor, composition of the liquid is changing - GS).

How do you know if something can be hydrolyzed to become a carboxylic acid or its salt? For example, how do you know the “derivatives” have this ability and what does the reaction look like? (A carbon must have three bonds (in any combination of single, double, and triple bonds) to atoms with at least one lone electron pair. - GS).

Will a Claisen condensation proceed under both acidic and basic conditions? (No, only under basic conditions, and only if that base is an alkoxide. Some other bases are possible, but rare. - GS).

What makes something a carboxylic acid derivative? (Ability to be hydrolyzed to a carboxylic acid or its salt. - GS).

Is there a difference between a reaction with “slight” heating vs. normal heating? Will it change anything? (Higher temperatures increase the reaction rate, decrease selectivity, favor enthropy-driven reactions, and may produce more gaseous compounds, which also plays to enthropy. - GS).

How do you know which carbon is the “alpha” carbon? (Next to the carbonyl group. - GS).

Dr. Sereda, I am having a hard time understanding how to identify lipids.  Could you possibly go over what makes a lipid tomorrow and how we identify them? (Lipids are natural compounds soluble in fats. - GS).

Dr. Sereda, what is the significance of “washing” something in lab? (Removing something ytou do not want or extracting something you want. - GS). For example, why do we wash some of our solutions with water and sodium bicarbonate? What does it do? (Either to remove an unwanted acid, or extract the desired compound to water as a carboxylate salt. - GS).

How does the alkaline hydrolysis work to produce a secondary amine? (Same way is for alkaline hydrolysis of esters, but with nitrogen instead of oxygen. See U.CAN - alkaline hydrolysis - GS).

Number four on last years quiz asks about why amides are much less basic than amines. I am under the assumption that this is due to resonance stabilization of amides. (You are correct. - GS).

Are amides much less basic, than amines because of their alkyl substituents at nitrogen? (No. Because of the carbonyl group withdrawing by conjugation the lone electron pair on nitrogen. - GS). Is that because of the resonance between them? (Yes. - GS).

Could you have a reaction between a carboxylic acid and an amine with a catalyst but without heating? (You need a reagent other than a catalyst, such as a carbodiimid derivative. - GS). Conversely, what about without a catalyst but with heating? Would these yield different answers if there is only one not both? (Either heat or a coupling reagent will produce an amide. - GS).

What is the product of a reaction between a carboxylic acid and an amine without heating, then? (Ammonium salt of carboxylic acid. - GS).

Dr. Sereda, what is the product of a reaction between a carboxylic acid and an amine with heating? Is it an amide? (Yes. - GS)

In general will a carboxylic acid + an alcohol with an acid catalyst result in the formation of an ester and water through Fischer Esterification? (Yes. The reverse reaction is called acid-catalysed hydrolysis of esters. - GS).

Is PCC’s job to turn alcohol into an aldehyde/ketone? (Yes. - GS).

Will acetal hydrolysis only happen under acidic conditions? (Yes. That is why non-reducing sugars can not open up to the reducing non-cyclic form. It is a very important question. - GS).

Is it any type of Sn1, E1, Sn2, E2, reaction? I thought you said something about that in class. (Conversion of hemiacetals to acetals (and the reverse reaction) is protonation followed by SN1 followed by deprotonation. - GS).

Is “Nucleophilic Addition to Carbonyl Group” an Sn1 reaction? (No. - GS).

What is supposed to happen to a enol when its in equilibrium with a ketone? (As a net result, hydrogen jumps between oxygen and carbon, end the double bond shifts from C=C to C=O. - GS).

Are hemiacetals very unstable and want to be acetals? (Usually yes, unless they are stabilized by cyclization. Example: alpha- and beta-glucose (and any other monosaccharide) are most favorable forms of glucose, and they are hemiacetals. They also tend to go back to the carbonyl compound and alcohol. - GS).

What are protecting groups (Removable groups stable under certain conditions. - GS) and why are acetals good ones? (They are stable in the presence of strong bases. - GS).

What exactly happens in a Friedel-Crafts Acylation? (Introduction of an acyl group into an aromatic ring by electrophilic substitution, catalyzed by a Lewis acid, most commonly AlCl3. - GS).

I recall you saying something about how in acidic conditions, something is deactivated, while something else is activated, and the opposite in basic. Would you mind stating this again? (Acids activate the carbonyl and deactivate the nucleophile by protonation. Bases may activate the nucleophile by deprotonation. - GS).

What is the PhC(O) benzoyl group and what is the significance? (It is a common part of many compounds such as acetophenone used in cosmetics, construction materials, and organic synthesis. It is also part of benzoic acid (conservant) and cocaine. That is just a few examples. - GS).

Dr. Sereda, what does “carb” meain in the name 2-methylcyclohexanecarbaldehyde? (It means that the aldehyde group contains a carbon, which is not a part of the principal chain. - GS).

(Here are 6 common pitfalls for chemical structure, bonding, and acids-bases: https://drive.google.com/file/d/0BxwgAv6oGg81aXM0WmxoYVU1WVk/view?usp=sharing   - GS).

I found this PDF about carbocations to be really helpful, if anyone else is interested!

http://www.chem.ucla.edu/harding/tutorials/cc.pdf (thank you!!)

-I’m not sure how many of you have heard of it, but I really enjoy KhanAcademy.org (Good job - GS).

Does a cyclopentane have double bonds anywhere on it? (No. - GS).

Dr. Sereda, would you mind posting on here what you said in class about how temperature and other factors affect reactions? (Higher temperature, stronger and more concentrated acid or base favor elimination, including dehydration on the last step of the aldol reaction. Generally speaking, higher temperature usually increases the reaction rate and favors entropy-driven equilibria. - GS).

In the formation of imines, is it always catalyzed by an acid? Or can the amine group attack as a nucleophile to the carbonyl carbon without the formation of a resonance stabilized carbonation? (Imines can form without acidic catalysis, but some other derivatives R-NH2 cannot. - GS).

Do ketones turn into enols? (Only if it has an alpha-hydrogen. - ) Is this reaction reversible?(Yes, as far as I know the reaction begins with a base, which puts a negative charge on the alpha carbon. When you then add acid, this would form an enol. The reaction will be reversible.-Anonymous rabbit) (Correct for both. - GS).

For formation of imine, enamine, hydrazone, are these in acidic conditions? (Each of those reactions has an optimal pH, depending on the substituent. - GS).

How do I tell the difference between an acetal and a hemiacetal by just looking at the structures. (Hemiacetals have an OH group, connected to the carbon, connected to oxygen. - GS).  All I understand is that hemiacetals are unstable and will go toward acetal formation  (Correct, only under acidic conditions. They will also go back to the carbonyl compound under any conditions. - GS).

I am not understanding the differences between an acid catalyzed aldol reaction (Enol plus activated carbonyl - GS). and a base catalyzed (Enolate plus non-activated carbonyl. - GS). aldol reaction.

Could you go over aldol reaction in class again? I just dont fully understand it. (OK. Briefly, it is just addition of an enol or enolate to an activated or non-activated carbonyl group, often followed by dehydration. - GS).

Does the formation of an acetal require alcohol and a proton? (Yes, and also an aldehyde or a ketone. - GS).

Could you go over aldol reaction in class again? I just dont fully understand it. (OK. Briefly, it is just addition of an enol or enolate to an activated or non-activated carbonyl group, often followed by dehydration. - GS).

I understand that the HCN adds to the aldehyde, so does this result in the formation of an alcohol? (Yes, which is also a nitrile. - GS).

What type of reaction is Cyanohydrin synthesis from (U.CAN)? (Nucleophilic addition to the carbonyl group. - GS).

What makes something an alpha position? (Next carbon. - GS).

Dr. Sereda, what does the prefix tert- mean? (Tertiary - GS).

Where does the “carb” come from for 2-methylcyclohexanecarbaldehyde? Is that just how you name it? (Yes, it is common for cyclic aldehydes.. - GS). Why is it different in the structure “3-methylbutanal”- is that not an aldehyde because it’s not cyclic? (Exactly. - GS).

When the pKa of a particular compounds is lower, does that mean it protonates more as opposed to if it were higher? (No, it is a stronger acid and tries to get rid of protons. - GS). Would it deprotonate at such higher pKas? (No - GS). Why is this?(Because at higher pH (it is a weaker acid and holds protons tighter. - GS).

How can a reactant mixture be made basic without adding a hydroxide salt? I know that if a salt contains an anion that reacts with water to produce hydroxide ions and also contains a cation that does not react with water then the resulting solution would be expected to be basic ... (Yes, this is one way. Another one is formation of hydroxide-anions in a redox-reaction. - GS).

Practical applications of organic chemistry in dentistry: https://drive.google.com/a/usd.edu/file/d/0BxwgAv6oGg81cDNlcGJ4RVpaNkk/view

U.CAN - Understand Curved Arrow Notation. Animation of organic reaction mechanisms:  http://ochem.orgfree.com/

Why does hydrogen bonding affect the boiling point? Yes I know this, but why? (It makes molecules stick to each other more and it takes more energy to separate them to the gas phase. Note: It does not apply to tertiary amines. - GS).

Dr. Sereda, in an acylation of amines, is it essentially a substitution reaction and the amine acts as a nucleophile? (Yes, it is an acyl substitution. The mechanism is similar to that shown in U.CAN for Fischer esterification. - GS). For instance, if an acyl group attached to a halide reacts with an amine group, des the halide act as a leaving group on the acyl group, and the amine attacks as a nucleophile (Yes. You are correct. - GS).

Dr. Sereda, amines with alkyl substituents increase in basicity up until the 3 substituent, why is that? (Due to better delocalization of the positive charge by substituents in the more substituted protonated form (ammonium). However, it works only for the gas phase. In solution, solvation kicks in, and things become more complicated. - GS).

Dr. Sereda, can you please go over acid/base strength of amines, specifically in benzene rings with multiple substituents? Thanks! (OK, Electron acceptors in the benzene ring, especially resonance acceptors in o- and p- positions further decrease basicity of amines. - GS).