## Search found 72 matches

Sat Mar 18, 2017 10:58 am
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Ring Flip
Replies: 4
Views: 902

### Re: Ring Flip

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!
Sat Mar 18, 2017 10:55 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Double Bonds
Replies: 1
Views: 610

### Double Bonds

When referring to a end to end overlap is that the sigma bond or the pi?
Sat Mar 18, 2017 10:54 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge [ENDORSED]
Replies: 4
Views: 747

### Salt Bridge[ENDORSED]

How do we know if the galvanic cell has a porous disk or a salt bridge? What's the difference between the two?
Sat Mar 18, 2017 10:53 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Final 2014 Question 3A
Replies: 3
Views: 444

### Re: Final 2014 Question 3A

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
Sat Mar 18, 2017 10:51 am
Forum: *Alkanes
Topic: Common Names
Replies: 1
Views: 694

### Common Names

Do we have to be familiar with any common naming since it was not discussed in the course reader or during class lectures?
Fri Mar 17, 2017 2:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Half-Reaction Voltages
Replies: 1
Views: 369

### Re: Half-Reaction Voltages

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 ...
Fri Mar 17, 2017 2:01 pm
Forum: *Alkanes
Topic: Organic molecule formulas
Replies: 2
Views: 874

### Re: Organic molecule formulas

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...
Fri Mar 17, 2017 1:57 pm
Forum: *Alkenes
Topic: Numbering Priority
Replies: 2
Views: 720

### Re: Numbering Priority

Functional groups should always be given priority with numbering, even if there is a lower numerical value that could be used instead.
Fri Mar 17, 2017 1:56 pm
Forum: Balancing Redox Reactions
Topic: Negative E
Replies: 1
Views: 336

### Re: Negative E

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...
Fri Mar 17, 2017 1:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Details and Review Sessions Winter 2017
Replies: 114
Views: 17779

### Re: Final Exam Details and Review Sessions Winter 2017

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 ...
Fri Mar 17, 2017 1:45 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Boat/Chair
Replies: 1
Views: 288

### Boat/Chair

If we are asked to draw the boat or chair conformations, do we need to draw all the hydrogens as well?
Fri Mar 17, 2017 1:44 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Ring Flip
Replies: 4
Views: 902

### Ring Flip

With the ring flip do the axial up become equatorial up?
Fri Mar 17, 2017 1:44 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Stability
Replies: 1
Views: 277

### Stability

What are the most stable cyclohexane conformations in order? Can you also explain what the favorable conformation for the substituents is as well
Thanks!
Fri Mar 17, 2017 1:42 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Cis Trans
Replies: 3
Views: 883

### Cis Trans

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
Fri Mar 17, 2017 1:41 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Axial/Equatorial
Replies: 2
Views: 349

### Axial/Equatorial

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?
Fri Mar 17, 2017 1:39 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Ring Flip
Replies: 1
Views: 296

### Ring Flip

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?
Fri Mar 17, 2017 1:37 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Constitutional v Geometric
Replies: 2
Views: 897

### Constitutional v Geometric

What is the difference between geometric isomers and constitutional isomers?
Sun Mar 12, 2017 4:44 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Transition State
Replies: 1
Views: 353

### Transition State

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?
Sun Mar 12, 2017 4:42 pm
Forum: *Carboxylic Acids
Topic: Carbonyl
Replies: 1
Views: 599

### Carbonyl

What is a carbonyl group? Is this the same as saying carboxylic acid?
Sun Mar 12, 2017 4:41 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: High Energy
Replies: 1
Views: 289

### High Energy

How do we know when the potential energy of a confirmation is high or low in order to identify it as gauche or anti?
Sat Mar 11, 2017 12:50 pm
Forum: *Alcohols
Topic: Alcohol
Replies: 1
Views: 247

### Alcohol

What does it mean for a -OH group to be attached to a secondary carbon atom?
Sat Mar 11, 2017 12:49 pm
Forum: *Alkenes
Topic: Double bonds
Replies: 1
Views: 261

### Double bonds

If there is a functional group and a double bond, which gets higher priority with the lowest numbering?
Sat Mar 11, 2017 12:48 pm
Forum: *Alcohols
Topic: Priority [ENDORSED]
Replies: 1
Views: 405

### Priority[ENDORSED]

When numbering functional groups, what is the order in which we give priority to the lowest value?
Sat Mar 11, 2017 12:47 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Cis and Trans [ENDORSED]
Replies: 1
Views: 359

### Cis and Trans[ENDORSED]

Do cis and trans also apply to triple bonds, or just double?
Fri Mar 10, 2017 2:52 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Conformations
Replies: 1
Views: 258

### Conformations

Why is the dihedral angle of 0 (as seen on page 107 of the course reader) considered a less stable conformation?
Fri Mar 10, 2017 2:50 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Energy and Angles page 107 in the course reader
Replies: 1
Views: 283

### Re: Energy and Angles page 107 in the course reader

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.
Fri Mar 10, 2017 2:47 pm
Forum: *Cyclopropanes and Cyclobutanes
Topic: Steric Strain
Replies: 2
Views: 824

### Re: Steric Strain

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...
Fri Mar 10, 2017 2:39 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Torsional Strain [ENDORSED]
Replies: 5
Views: 804

### Torsional Strain[ENDORSED]

Does torsional strain only occur when the conformation is eclipsed?
Fri Mar 10, 2017 2:37 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Gauche
Replies: 1
Views: 290

### Gauche

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?
Fri Mar 10, 2017 2:32 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: different conformation
Replies: 1
Views: 267

### Re: different conformation

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...
Fri Mar 10, 2017 12:57 pm
Forum: *Alkanes
Topic: Tert vs. Neo?
Replies: 4
Views: 633

### Re: Tert vs. Neo?

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 ...
Fri Mar 10, 2017 12:56 pm
Forum: *Alkanes
Topic: Iso / Neo when to use
Replies: 3
Views: 520

### Re: Iso / Neo when to use

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...
Fri Mar 10, 2017 12:54 pm
Forum: *Amines
Topic: Numbering of carbons in amines
Replies: 1
Views: 645

### Re: Numbering of carbons in amines

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...
Fri Mar 10, 2017 12:50 pm
Forum: *Alkanes
Topic: "Iso"
Replies: 3
Views: 481

### Re: "Iso"

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.
Fri Mar 10, 2017 12:47 pm
Forum: *Alkanes
Topic: Arranging substituents while naming
Replies: 2
Views: 388

### Re: Arranging substituents while naming

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...
Fri Mar 10, 2017 12:42 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Details and Review Sessions Winter 2017
Replies: 114
Views: 17779

### Re: Final Exam Details and Review Sessions Winter 2017

Will the list continue to be updated with what each TA will be reviewing in the sessions?
Thu Mar 09, 2017 8:33 pm
Forum: *Alkenes
Topic: Cis and Trans
Replies: 2
Views: 368

### Cis and Trans

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?
Mon Mar 06, 2017 8:45 pm
Forum: *Alkanes
Topic: Tert- Naming
Replies: 2
Views: 420

### Tert- Naming

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?
Sat Mar 04, 2017 4:02 pm
Forum: *Cycloalkenes
Topic: Correct Naming [ENDORSED]
Replies: 1
Views: 303

### Correct Naming[ENDORSED]

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?
Fri Mar 03, 2017 2:17 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

Why did Carbon marry Hydrogen?
They bonded well from the minute they met
Fri Mar 03, 2017 2:16 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

Why do chemists learn about ammonia first?
It's pretty basic stuff.
Fri Mar 03, 2017 2:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."
Fri Mar 03, 2017 2:08 pm
Forum: *Cycloalkanes
Topic: Tert- Naming
Replies: 4
Views: 1700

### Tert- Naming

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?
Fri Mar 03, 2017 2:06 pm
Forum: *Cycloalkanes
Topic: Common Prefix
Replies: 1
Views: 293

### Common Prefix

What do the terms "neo" and "iso" tell us regarding the structure of the molecule?
Fri Mar 03, 2017 2:04 pm
Forum: *Cycloalkanes
Topic: Common Names
Replies: 3
Views: 496

### Common Names

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?
Thu Mar 02, 2017 9:17 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

Making bad chemistry jokes because all the good ones Argon
Thu Mar 02, 2017 9:17 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

H2O is water and H2O2 is hydrogen peroxide. What is H2O4?
Drinking.
Thu Mar 02, 2017 9:16 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

Did you know that you can cool yourself to -273.15˚C and still be 0k?
Thu Mar 02, 2017 9:16 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8030
Views: 1407391

### Re: Post All Chemistry Jokes Here

Don't trust atoms, they make up everything.
Thu Mar 02, 2017 9:11 pm
Forum: *Alkanes
Topic: Ambidentate nucleophiles
Replies: 2
Views: 419

### Re: Ambidentate nucleophiles

Is an ambient nucleophile just another term for this?
Thu Mar 02, 2017 9:08 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Substituent
Replies: 1
Views: 365

### Substituent

Can the term "substituent" refer to any molecule not part of the parent chain?
Thu Mar 02, 2017 9:07 pm
Forum: *Alkanes
Topic: Drawing Organic Molecules
Replies: 1
Views: 301

### Drawing Organic Molecules

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?
Thu Mar 02, 2017 9:06 pm
Forum: *Cycloalkanes
Topic: Drawing Structures
Replies: 1
Views: 258

### Drawing Structures

What is the difference between drawing a line structure and drawing a ring?
Thu Mar 02, 2017 9:04 pm
Forum: *Alkanes
Topic: Primary Carbon Atom
Replies: 1
Views: 253

### Primary Carbon Atom

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.?
Thu Mar 02, 2017 9:02 pm
Forum: *Alkanes
Topic: Alkanes
Replies: 1
Views: 322

### Alkanes

How would we know that a structure is a cycloalkane rather than an alkane? Is this something that would be given to us?
Thu Mar 02, 2017 9:01 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Thermodynamic Stability
Replies: 1
Views: 284

### Thermodynamic Stability

Why are products thermodynamically more stable when the standard reaction Gibbs free energy is negative and reactants more thermodynamically stable if it is positive?
Thu Mar 02, 2017 8:59 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Kinetic Stability
Replies: 1
Views: 245

### Kinetic Stability

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?
Thu Mar 02, 2017 8:55 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Exergonic Reaction
Replies: 2
Views: 426

### Exergonic Reaction

What does it mean for a reaction to be exergonic other than that is has a negative standard reactions Gibbs free energy?
Thu Mar 02, 2017 8:54 pm
Forum: *Alkynes
Topic: Naming an Alkyne
Replies: 1
Views: 647

### Naming an Alkyne

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?
Thu Mar 02, 2017 8:52 pm
Forum: *Alkanes
Topic: Drawing Organic Molecules
Replies: 1
Views: 271

### Drawing Organic Molecules

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?
Thu Mar 02, 2017 8:50 pm
Forum: *Alkenes
Topic: Assigning Priority
Replies: 1
Views: 279

### Assigning Priority

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?
Thu Mar 02, 2017 8:45 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Mechanisms
Replies: 2
Views: 387

### Mechanisms

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?
Thu Mar 02, 2017 8:43 pm
Forum: *Nucleophiles
Topic: Ambident
Replies: 3
Views: 464

### Ambident

What does it mean to be an ambident nucleophile? Can someone give an example of how it could possibly be expressed?
Thu Mar 02, 2017 8:41 pm
Forum: *Cycloalkenes
Topic: Geometric Isomers
Replies: 2
Views: 793

### Geometric Isomers

What are geometric isomers and how do they differ from constitutional isomers?
Fri Feb 24, 2017 3:05 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Nucleophiles
Replies: 2
Views: 409

### Nucleophiles

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?
Fri Feb 17, 2017 2:45 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Mechanisms
Replies: 2
Views: 372

### Mechanisms

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?
Fri Feb 10, 2017 7:12 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Electrolysis
Replies: 1
Views: 348

### Electrolysis

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?
Fri Feb 03, 2017 4:30 pm
Forum: Balancing Redox Reactions
Topic: Electrodes
Replies: 2
Views: 327

### Electrodes

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?
Fri Feb 03, 2017 4:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Extensive v Intensive
Replies: 2
Views: 399

### Extensive v Intensive

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?
Fri Jan 27, 2017 3:41 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous
Replies: 1
Views: 283

### Spontaneous

Why is any decrease in Gibbs free energy, or negative delta G, considered favorable?
Fri Jan 20, 2017 6:19 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy
Replies: 2
Views: 356

### Entropy

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?
Thu Jan 12, 2017 6:46 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 7
Views: 526

### Bond Enthalpies

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...