## Search found 20 matches

Mon Mar 07, 2016 4:15 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Rotation of Carbon Bonds
Replies: 2
Views: 462

### Re: Rotation of Carbon Bonds

From my understanding of the rotation graphs with the energies on them, the direction of rotation does not result in different conformations because the conformation follow a symmetric pattern. In other words, a 60 degree rotation clockwise or counterclockwise (300 degrees) both result in the same c...
Mon Feb 29, 2016 4:34 pm
Forum: *Alkanes
Topic: Tert and Sec
Replies: 2
Views: 240

### Re: Tert and Sec

Tert and Sec are part of the common names. I think this picture at the link may help. We can see that tert is a carbon attached to the parent string, with 3 methyls (CH3) coming off of it. On the other hand, Sec has one carbon attached to the parent string, with one methyl (CH3) and one ethyl (CH2CH...
Mon Feb 22, 2016 6:53 pm
Forum: *Cycloalkanes
Topic: Quiz 3 prep #1 Cyclo problem
Replies: 2
Views: 424

### Re: Quiz 3 prep #1 Cyclo problem

According to the course reader, for cycloalkanes with 2 substituents, whichever substituent you name first gets the lower number. Therefore, in the answer to this problem, 1 would come before 3 in 1-chloro-3methylcyclopentane. Hope this helps!
Mon Feb 15, 2016 9:08 pm
Forum: First Order Reactions
Topic: solving for [A]t
Replies: 1
Views: 336

### Re: solving for [A]t

We can use the first order integrated rate law in this problem, [A]t = [A]0*e^-kt. This looks to be the same problem as 15.23 in the textbook, so we need to find k. However, to calculate [A]t, we can use the reaction formula given. We see that for every mol of B formed, 2 mol of A is used. Therefore...
Mon Feb 08, 2016 4:22 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics
Replies: 1
Views: 351

### Re: Kinetics

A diamond is thermodynamically unstable (the beginning and end result of the reaction) because the reaction which turns diamond into graphite has a negative Gibbs free energy value, making the reaction spontaneous. However, when looking at the kinetics (the middle process of going from diamond to gr...
Sun Jan 31, 2016 9:43 pm
Forum: Balancing Redox Reactions
Topic: oxidation vs reduction
Replies: 2
Views: 373

### Re: oxidation vs reduction

From how I understand it, the transfer of electrons in a reaction can create electrical energy. A molecule is oxidized when it loses an electron in a chemical reaction. On the other hand, a molecule is reduced when it gains an additional electron in a chemical reaction. This is important in that in ...
Mon Jan 25, 2016 5:41 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Finding the number of states a molecule can be in
Replies: 1
Views: 362

### Re: Finding the number of states a molecule can be in

I find that drawing a hypothetical Lewis structure helps in finding the number of possible states. For this specific one, the central atom M has 6 total bonds around it (2X and 4Y). If we place the 2X bonds across from each other, we reach the trans-state. However, those 2X's can be placed opposite ...
Mon Jan 18, 2016 9:02 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed vs. Isolated System
Replies: 2
Views: 469

### Re: Closed vs. Isolated System

If I remember correctly, the first law of thermodynamics works because the universe is considered an isolated system. Therefore, we can conclude that the energy inside the universe is constant and come up with a law such as conservation of energy.
Mon Jan 11, 2016 4:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Units
Replies: 3
Views: 499

### Re: Units

Does the molar heat capacity always have units of J and K^-1 instead of kJ and C^-1? Or is it based on the preference of the user? Which units are preferred? If I understood it correctly, both J.K^-1 and kJ.C^-1 can be used for molar heat capacity, but it just depends on if the problem is using kil...
Fri Jan 08, 2016 4:44 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Work
Replies: 2
Views: 483

### Re: Calculating Work

From how I understood it, the more negative the number, the more work it is. Therefore, -344J would be more work than -122J.
Mon Nov 30, 2015 2:15 pm
Forum: Bronsted Acids & Bases
Topic: Formic Acid vs. Acetic Acid
Replies: 2
Views: 442

### Re: Formic Acid vs. Acetic Acid

I'm not quite sure on the exact answer, but I'll give it a shot. When we look at the CH3 Lewis structure, we see that the carbon has 1 unpaired electron, making it more unstable and want to 'donate' that lone electron. Therefore, the carbon will not hold the electron as strongly, as it is trying to ...
Mon Nov 23, 2015 3:58 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining coordination number
Replies: 2
Views: 603

### Re: Determining coordination number

From my understanding, the coordination number refers to the number of atoms bonded to the central metal. Therefore, double bonds would still only contribute 1 to the coordination number. However, it is possible for a molecule to bind to the central metal in more than one place, causing polydentate ...
Mon Nov 16, 2015 3:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Terminology
Replies: 1
Views: 294

### Re: Equilibrium Terminology

I think both terms mean that reactants will be favored in the reaction, but each term is used for a different case. "Shifted to the left" can mean that reactant formation will be favored when more products are added to the reaction. "Lie to the left" can mean that the reaction na...
Mon Nov 09, 2015 1:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table
Replies: 2
Views: 426

### Re: ICE table

From my understanding, the ice table is used when we don't know the change in molar concentration for reactants and products. Therefore, we cannot figure out what the molar concentration would be at equilibrium. I'm not sure of a situation in which we would ignore x within an ice table, as it is ess...
Mon Nov 02, 2015 2:36 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Diamagentism vs Paramagnetism
Replies: 3
Views: 260

### Re: Diamagentism vs Paramagnetism

From my understanding, the atomic orbitals are only used to assist us in seeing how the molecular orbitals are filled and what energy levels they are. Therefore, we only use the molecular orbitals to identify magnetism. If there are unpaired electrons, it is considered a paramagnetic molecule; if th...
Mon Oct 26, 2015 1:17 pm
Forum: Electronegativity
Topic: Central atom of Lewis Dot Structure
Replies: 2
Views: 656

### Re: Central atom of Lewis Dot Structure

I also find using electronegativity to choose the central atom easier because the definition seems to be easier to connect to the topic. However, in the periodic table, ionization energy and electronegativity have the same patterns: both increase across a period and up a group. Therefore, there is n...
Tue Oct 20, 2015 1:39 pm
Forum: Resonance Structures
Topic: Negative electron
Replies: 1
Views: 392

### Re: Negative electron

Showing the different angles in a Lewis structure show the effect of lone pairs in a molecule. It also relays the concept of how the individual electron densities will work to create a maximum distance from each other as possible. If I'm not mistaken, the angles in a Lewis structure and resonance st...
Tue Oct 20, 2015 1:30 pm
Forum: Lewis Structures
Topic: Lewis structure for glycine
Replies: 2
Views: 1271

### Re: Lewis structure for glycine

I believe the 2 oxygens do have to bond with the same carbon, as they are all together part of the third molecule (COOH). However, I think the entire molecule can move around to the opposite side for example and create a resonance structure. Hopefully this helps and doesn't lead you in the wrong dir...
Thu Oct 08, 2015 3:33 pm
Forum: Quantum Numbers and The H-Atom
Topic: N increase
Replies: 2
Views: 402

### Re: N increase

I thought of it as an increase in "n" inherently implies that there was an increase in energy. This is because in order for an electron to become excited to a higher "n" level, it must absorb a certain amount of energy. Thus, we can come to the conclusion that an increase in &quo...
Thu Oct 01, 2015 3:05 pm
Forum: Properties of Light
Topic: Question: Wave Model vs. Photon Model of Light
Replies: 7
Views: 2319

### Re: Question: Wave Model vs. Photon Model of Light

I understood it as the experiment involving the Photoelectric Effect indicated that it was the frequency of light that determined whether or not electrons were released, rather than the intensity. Therefore, it showed that light has both wave and particle properties, and in this case it was the part...