CHEMISTRY COMMUNITY

Dianna Grigorian 1C

Timothy_Yu_Dis3A wrote:Yes, during a ring flip, the axial up's become equatorial up's and vice versa.

Consequently, axial down's will become equatorial down's and vice versa.

Here's a nice diagram of the ring flip of a cyclohexane in chair conformation that illustrates this.

This makes sense thanks!

Dianna Grigorian 1C

When referring to a end to end overlap is that the sigma bond or the pi?

Dianna Grigorian 1C

How do we know if the galvanic cell has a porous disk or a salt bridge? What's the difference between the two?

Dianna Grigorian 1C

I had the same question since the chart was not provided in the question with the reduction values. But, I think in order to calculate the cell voltage we would have to be given the numbers so we could use that to figure it out

Dianna Grigorian 1C

Do we have to be familiar with any common naming since it was not discussed in the course reader or during class lectures?

Dianna Grigorian 1C

Usually when we are given the E values, they are in the reduction form. However, for a galvanic cell, we need one reduction half and one oxidation. This is why we flip one of the reactions. Usually we flip the one that would give us an overall positive and favorable E value. However, sometimes this ...

Dianna Grigorian 1C

I don't know if we necessarily have to memorize the general formulas, but it might help to be familiar for them. For instance, alkanes have the form (C2nH2n+2) Alkenes (C2nH2n) Alkynes (C2nH2n-2) I find that it is also helpful to draw out the structures if you are unsure and count the number of mole...

Dianna Grigorian 1C

Functional groups should always be given priority with numbering, even if there is a lower numerical value that could be used instead.

Dianna Grigorian 1C

I think that we primarily distinguish between the anode and cathode by the sign of the E value so whether it will be positive or negative in order to provide a favorable E. However, when some problems give the chemical equation and we need to write the half reactions, we need to be consistent with t...

Dianna Grigorian 1C

Seeing as how many of us were surprised by the midterm question asking us to derive the nernst equation, which equations should we know how to derive for the final? According to Professor Lavelle, we will not need to know how to derive any equations on the final. It will focus primarily on problem ...

Dianna Grigorian 1C

If we are asked to draw the boat or chair conformations, do we need to draw all the hydrogens as well?

Dianna Grigorian 1C

With the ring flip do the axial up become equatorial up?

Dianna Grigorian 1C

What are the most stable cyclohexane conformations in order? Can you also explain what the favorable conformation for the substituents is as well
Thanks!

Dianna Grigorian 1C

I'm still a little confused on how we can identify "cis" or "trans" on a cyclohexane with regards to the substituent groups. Can someone please explain this again

Dianna Grigorian 1C

How do we draw the equatorial and axial bonds so that they are alternating? Is there a preference for where we start, or can it be any of the corners as long as it is consistent?

Dianna Grigorian 1C

Can someone explain what it means for the ring flip to occur? Is there a certain reason why we need to draw it, or is it just to show another energy structure?

Dianna Grigorian 1C

What is the difference between geometric isomers and constitutional isomers?

Dianna Grigorian 1C

When do we indicate the charges of the atoms when drawing a reaction mechanism? Is it just in the transition state to show which bonds form/break?

Dianna Grigorian 1C

What is a carbonyl group? Is this the same as saying carboxylic acid?

Dianna Grigorian 1C

How do we know when the potential energy of a confirmation is high or low in order to identify it as gauche or anti?

Dianna Grigorian 1C

What does it mean for a -OH group to be attached to a secondary carbon atom?

Dianna Grigorian 1C

If there is a functional group and a double bond, which gets higher priority with the lowest numbering?

Dianna Grigorian 1C

When numbering functional groups, what is the order in which we give priority to the lowest value?

Dianna Grigorian 1C

Do cis and trans also apply to triple bonds, or just double?

Dianna Grigorian 1C

Why is the dihedral angle of 0 (as seen on page 107 of the course reader) considered a less stable conformation?

Dianna Grigorian 1C

I think the primary reason why gauche has a lower energy than eclipsed is because it is still considered staggered, so has less electron density repulsion unlike the eclipsed which are in closer proximity and therefore has more repulsion and energy.

Dianna Grigorian 1C

Sterin strain occurs when the atoms physically bump into each other. It happens when nonbonded atoms interact with each other and are too close. Torsional strain is the force that oppose rotation of a part of a molecule about a bond. In other words, it is the electron density repulsion that limits t...

Dianna Grigorian 1C

Does torsional strain only occur when the conformation is eclipsed?

Dianna Grigorian 1C

Can someone please describe the gauche conformation and any of its distinct features? I understand that it is the second most stable state and is staggered, but is there a certain way to identify it?

Dianna Grigorian 1C

Because the staggered conformation has C-H bonds on adjacent C, they are further away from each other. This means that there is greater space between the atoms and they are further away from the electron density regions that cause repulsion. With the eclipsed conformation, however, the C-H bonds are...

Dianna Grigorian 1C

Both "tert" and "neo" are prefixes that apply to the structural arrangement of the subsistent bonded to the carbon atom. However, I think the difference between the two is that tert refers to the plus-like shape that has four carbons, whereas neo is used when there are 5 or more ...

Dianna Grigorian 1C

The prefixes "iso" and "neo" refer to the structural arrangement of the substituent bonded to the carbon atoms. I think to determine whether we need to include them in the names we just need to be familiar what each is. Iso is attached at one end and branches at the other, simila...

Dianna Grigorian 1C

When numbering such structures, I believe it is best to number the carbons in order to provided the lowest numbering to all the attached substituents. If I'm not mistaken, the nitrogen aspect of the amine would be treated similar to other substituents so we would number the carbons to give the lowes...

Dianna Grigorian 1C

The prefix "iso" refers to the structural arrangement of the subsistent group around the carbon. In this example, "iso" is used because the substituent is attached at one end and branches at the other, forming a Y-like shape.

Dianna Grigorian 1C

The prefixes "di" and "tert" do not appear when putting them alphabetically because it is a prefix regarding the number of carbons bonded together. However, common name prefixes such as "neo" and "iso" are included when arranging the substituent alphabetically...

Dianna Grigorian 1C

Will the list continue to be updated with what each TA will be reviewing in the sessions?

Dianna Grigorian 1C

Since "trans" and "E" both refer to the highest priority groups being on opposite side of a double bond, does that mean they can be used interchangeably to name the molecule?

Dianna Grigorian 1C

When naming an organic structure and we find it to be a tertbutyl, how do we place this alphabetically? Do we look at "tert" as we did with iso and neo and include it in the alphabetical arrangement, or should we treat it like the Greek prefixes and ignore it?

Dianna Grigorian 1C

Where does the suffix "diene" come from? For example in problem 1.21, why is the correct answer 5-Methylcyclopenta-1,3-diene and not 5-Methyl-1,3-Cyclopentene?

Dianna Grigorian 1C

Why did Carbon marry Hydrogen?
They bonded well from the minute they met

Dianna Grigorian 1C

Why do chemists learn about ammonia first?
It's pretty basic stuff.

Dianna Grigorian 1C

A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."

Dianna Grigorian 1C

I'm a little confused on when we include the prefix tert- in the naming of an organic molecule. Why in the example from the course reader the molecule has to have the perpendicular bond and be named tert-butyl? Can it not be linear instead of adding this type bond?

Dianna Grigorian 1C

What do the terms "neo" and "iso" tell us regarding the structure of the molecule?

Dianna Grigorian 1C

In regards to the example from class today, how do we know to include "iso" in the naming of the molecule? When should this be included and when is it not needed?

Dianna Grigorian 1C

Making bad chemistry jokes because all the good ones Argon

Dianna Grigorian 1C

H2O is water and H2O2 is hydrogen peroxide. What is H2O4?
Drinking.

Dianna Grigorian 1C

Did you know that you can cool yourself to -273.15˚C and still be 0k?

Dianna Grigorian 1C

Don't trust atoms, they make up everything.

Dianna Grigorian 1C

Is an ambient nucleophile just another term for this?

Dianna Grigorian 1C

Can the term "substituent" refer to any molecule not part of the parent chain?

Dianna Grigorian 1C

When we are given a formula and it has parentheses in it such as CH3(CH2)3CH3, does that mean that those atoms are substituents and not part of the parent chain?

Dianna Grigorian 1C

What is the difference between drawing a line structure and drawing a ring?

Dianna Grigorian 1C

When would we refer to a molecule by identifying the number of carbons atoms to which each carbon is attached to i.e. when do we characterize it as a primary carbon atom, secondary, etc.?

Dianna Grigorian 1C

How would we know that a structure is a cycloalkane rather than an alkane? Is this something that would be given to us?

Dianna Grigorian 1C

Why are products thermodynamically more stable when the standard reaction Gibbs free energy is negative and reactants more thermodynamically stable if it is positive?

Dianna Grigorian 1C

According to the organic chemistry textbook, reactants are described as kinetically stable when the standard Gibbs free energy of activation is large. Does this mean that the larger the delta G of transition, the slower the reaction?

Dianna Grigorian 1C

What does it mean for a reaction to be exergonic other than that is has a negative standard reactions Gibbs free energy?

Dianna Grigorian 1C

In the textbook on page 19, an example is given of naming an alkyne with the formula (CH3)2CHC --- CH. How do we know that the longest carbon-carbon chain has four bonds and should be butyne rather than a chain of 5 carbons?

Dianna Grigorian 1C

When drawing the organic molecules, how do we know if it should be a linear chain or have branches if we are just given the molecular formulas?

Dianna Grigorian 1C

What does it mean to assign priority to atoms bonded to sp^2 carbon atoms as explained in the book on page 16? Is this something we would need to do and if so, when?

Dianna Grigorian 1C

Are the only mechanisms we need to know electrophilic addition and bimolecular nucleophilic substitution? Or, should we also look at electrophilic aromatic substitution that is in chapter 4 of the organic chemistry textbook?

Dianna Grigorian 1C

What does it mean to be an ambident nucleophile? Can someone give an example of how it could possibly be expressed?

Dianna Grigorian 1C

What are geometric isomers and how do they differ from constitutional isomers?

Dianna Grigorian 1C

I understand that the nucleophile is the electron rich species that likes a positively charged nucleus. Does this mean that the nucleophiles have a net negative charge and are attracted to the positive charge on other elements?

Dianna Grigorian 1C

I understand what a reaction intermediate is, but why do we need it? How do we know what it is for a particular reaction, and when do we know to include it in the steps?

Dianna Grigorian 1C

Can someone clarify what an electrolysis reaction is? What is the relationship between a redox reaction and electrolysis, and is this something we can calculate?

Dianna Grigorian 1C

During the lecture, Professor Lavelle used an example to explain the the cathode needed an electrode, so we used an inert conductor to transfer electrons. How do we know if we should include an electrode in our reaction, and why is it needed?

Dianna Grigorian 1C

I understand that the difference between extensive and intensive properties is that extensive depends on the amount of material, while intensive does not. But, why does that make intensive properties more useful?

Dianna Grigorian 1C

Why is any decrease in Gibbs free energy, or negative delta G, considered favorable?

Dianna Grigorian 1C

In todays lecture, Professor Lavelle introduced the idea of entropy. I understand that entropy is an extensive property, so it depends on the number of particles. It is also a measurement of the degree of disorder in a system. But, what is the relationship between entropy and energy?

Dianna Grigorian 1C

To calculate what delta H is for a particular reaction using bond enthalpies (method 2), we have to know the structure with which the bonds break in the reactants and the new bonds are formed in the products. But, how do we know which bonds require energy and are broken, and which bonds release ener...

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