Could you explain why we would want to attempt to remove an impurity of a water insoluble thiol from a water insoluble alcohol by washing with aqueous NaOH? (Thiols are more acidic than alcohols, so can be significantly deprotonated in an aqueous solution at pKa 14 or less. - GS).

^^^So would the same answer apply if the question was to attempt to remove an impurity of a water insoluble alcohol from a water insoluble ester? (No. pKa of alcohols are about 15. - GS).

What is the overall synthetic outcome of hydroboration of alkenes, followed by oxidation?” I know hydroboration is against Markovnikov’s rule.  Is the answer addition of water against markovnikov’s rule (Yes. - GS) or addition of boron in the syn-fashion against the Markovnikov’s rule? (No, because it is followed by oxidation. - GS).

^^^^^^Just out of curiousity what would the product be if this reaction (addition of water against the markovnikov's rule) took place assuming that the alkene was like ethene? (Ethanol, but for this example, the rule does not apply because both carbons have same number of hydrogens. - GS).

In general I was wondering is there a “clue” that allows you to tell whether the reaction is first order or second order, (Usually it is same as the number of particles interacting on the rate-limiting step. - GS). I can easily differentiate between E and S reactions and can also tell when its SN1 or Sn2 when the reaction is written out even if only partially written out but I sm still struggling with which is which “verbally”?  (The best illustration is given by U.CAN. - GS).

Is more branched more stable? (For the alkane chain - usually yes. - GS).

A good leaving group is a weak base correct? (Yes. - GS).

”Polymerization of which compound will produce a polymer with the following structure?” What is the answer and how did you get that? (Take out the repeating polymer chain fragment and complete the free valencies with double bonds. - GS).

How can you rotate around a pi bond in a butane molecule? (No, there is no such bond. - GS). I thought all bonds in butane are sigma? (Correct. - GS).

Surface of potential energy is given by heat effect, number of steps, reaction rates for all steps

Balanced chemical equation is given by molecular coefficients for all reactants and products

Curved arrrow. .  .  redistribution of electrons and charges between the nuclei

Is this correct? (Yes. - GS).

For those struggling with formal charge, this video is very helpful. https://www.khanacademy.org/science/organic-chemistry/organic-structures/formal-charge-resonance/v/formal-charge-i  (Very good video. Formal charges are also connected to molecular geometry. However, students who attended my lectures will find it redundant. - GS).

Dr. Sereda, is Br the only element that can exceed it’s octect? (No. Any element of period 3 and higher can do it. - GS). Carbon and oxygen cannot? (Correct. They are in period 2 - GS).

Dr. Sereda, how do you know if a compound contains only primary hydrogens? (It happens when the compound has only primary carbons that bonded to hydrogens. - GS).

Is 2,2-dimethylpropane a compound that only has primary hydrogens? (Yes. - GS).

Is trans generally more stable than cis? (Yes, for linear hydrocarbons - for sure. - GS).

Does the fact that a molcule is a primary, seconadary, tertiary,etc carbon really matter if it is given that the octet is complete for the carbon? (“Primary” etc refers to carbons, not molecules. - GS). Wouldnt the formal charge always just be zero for carbon if the octet is complete? (No. It is zero when carbon forms 4 covalent bonds and in some other cases, such as free radical and carbene. - GS).

Different strength of attraction between molecules of alkanes makes possible to separate petroleum into heating gas by distillation correct? (Yes, because of different boiling points. - GS).

Is staggered more stable than eclipse conformation? (Yes, for alkanes. - GS).

Is it correct that a chiral center must have four different substituents attached? (Yes, counting hydrogen. - GS).

Staggered configuration is more stable than eclipsed correct? (Yes for alkanes because of the prevalence of steric repulsion. For other types of compounds, it depends on the individual intramolecular interactions. - GS).

How are heterocyclic amines (HCAs) form from cooking and how do we avoid this cancer-causing, adduct-forming agents? Giving up steak is NOT an option. (It is a series of aldol condensations, dehydrations, oxidations, and cyclizations, which can be minimized by steam cooking or pressure cooking with antioxidant herbs. The art is to maintain temperature high enough to give you a yummy crust, but too low to induce the above listed reactions. High pressure of water vapor also keeps dehydrations under control. The carcinogenic polycyclic aromatic compounds are especially easily formed from steroid hormones that could be given to the animal to accelerate its growth, or could be produced by the animal’s body when it is under stress and abused. Nature has its ways for fighting back. - GS).

Can you explain the difference between stereoisomers and constitutional isomers? (In constitutional isomers, atoms are connected in a different order. In stereoisomers, atoms are connected in the same order, but are placed at different locations. - GS).

Dr. Sereda, is the formula for cycloalkanes CnH2n? (Yes, and also for alkenes. - GS). Consequently, is the formula for alkanes CnH2n+2? (Yes. - GS).

What makes something a chiral center vs. an achiral center? (A chiral center must have all four attached groups different. - GS).

I’m having trouble understanding the difference between constitutional isomers and identical isomers. Could you explain this? (There are no identical isomers. Isomers must be different compounds. - GS).

Can you go over the differences between ‘R’ and ‘S’ compounds? (There are no R- and S-compounds. This term refers to chiral centers. - GS). Do these only apply to enantiomers? (No. It applies to any chiral center. - GS).

So when the pH equals the pKa, in this case when the pH=9, then the amino groups would only be half protonated, correct? (Almost. Half of them will be fully protonated. - GS)

Is the hydrogen on the alpha carbon more acidic than the hydrogen on the OH group of the carboxylic acid?  (Their pKas are about 17 and 5 correspondingly. - GS.) What about if there are two carbonyl groups attached by an alpha carbon? (That pKa is about 9 - GS).

Acid donates H+, does conjugative acid accept H+? (No. Bronsted bases accept H+ - GS).

What was it you said in lecture about if the pKa>pH then that means. .  . ? I know on the blog you said pKa = pH, the concentrations of acid and conjugate base are equal, but does that mean that if the pKa>pH the concentration of the conjugate base is greater than the concentration of acid?  (No. Equilibrium favors the acid under those conditions. - GS).

I’m still having a little trouble in relating pKa to pH in terms of deprotonation. (If pKa = pH, the concentrations of acid and conjugate base are equal. - GS)

Dr. Sereda, what is the difference in the apparatus between a distillation and reflux? (In distillation, the distillate is taken out, in refluxing - it is dripping back. - GS).

Dr. Sereda, when we “wash” something in lab with a separatory funnel, is that an example of extraction? (Yes. - GS).

If you increase atmospheric pressure will it INCREASE or DECREASE the boiling point. (It will increase the boiling point, because it will require a higher temperature to raise the vapor pressure up to the atmospheric pressure. - GS).

Dr. Sereda, what are desirable characteristics of solvents for recrystallization (Higher solubility at higher temperatures and lower solubility at lower temperatures, non-reactivity with the compound, ease of removal, but other scenarios are possible. - GS). and extraction? (Higher solubility of the desired compound and lower solubility of non-desired compounds, immiscibility with the liquid you are extracting from, non-reactivity with the compound, ease of removal. - GS)

What type of reaction is shown for the synthesis of the alkenes? (4-methyl-2-pentanol +SOCl2→ 4-methyl-2-chloropentane and then add CH3CH2ONa and CH3CH2OH and heat → Alkenes) Does is proceed by an E2 mechanism because it is a secondary alcohol? (Yes, because alkoxide is a strong base. - GS).  Are there any hydride or alkyl shifts in this case?  (No, because there are no carbocations involved. - GS).

I looked up distribution coefficient on the internet but I am having some trouble understanding it for the liquid-liquid extraction. Do you have a simple definition? and then how do you calculate it? Then when you know K what does it mean to have a large K versus a small K? (The distribution coefficient is the ratio of concentrations of a compound in different phases. If it significantly differs from 1, than most of the compound went to one phase. If it is about 1, the concentrations are equal. The more different the distribution coefficients are for different compounds, the better the separation is. - GS).

Dr. Sereda, is the reaction between phenylmagnesium bromide and CO2 form a benzene ring bonded to a carbon(which is double bonded to oxygen), bonded to an O with a negative charge? (Yes. It produces a benzoate. - GS).

Dr. Sereda, would the reaction between phenylmagnesium bromide and H2o form a benzene ring with a hydrogen coming out?(Yes. It will be just benzene itself. - GS).

So I don’t need to draw the hydrogen coming out of the ring? (No. It is implied by the valency of carbon. - GS).

Just making sure: when a carboxylic acid and an amine react without heat and without a catalyst the product is an ammonium salt but when a carboxylic acid and an amine react with either heat or with a catalyst the product is an amide? (You are correct. - GS).

What are the conditions for acyl substitution? (It depends on the nucleophile and the leaving group. - GS). When will it produce a carboxylic acid derivative versus a salt? (Salt is also considered a carboxylic acid derivative and is produced under alkaline hydrolysis, that is with OH- as the nucleophile. - GS).