Search found 25 matches

by GunvantChaudhari 2F
Thu Mar 10, 2016 11:02 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: pseudo equilibrium constant
Replies: 2
Views: 791

Re: pseudo equilibrium constant

A pseudo equilibrium constant is just a way of differentiating the equilibrium constant of the entire reaction from that of just the transition state. Honestly don't worry too much about it; it is just a way of representing the phenomenon of molecules going back and forth from the reactants and the ...
by GunvantChaudhari 2F
Mon Mar 07, 2016 1:08 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Gauche vs Anti Stability
Replies: 1
Views: 720

Re: Gauche vs Anti Stability

In the anti conformation, the hydrogen atoms of the 1 and 4 carbons are as far away as possible, whereas in the gauche conformation, these atoms are still pretty close to each other, but staggered. So I guess the difference has to do more with steric strain.
by GunvantChaudhari 2F
Sun Feb 28, 2016 1:33 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Interesting Research on Transition States
Replies: 2
Views: 397

Re: Interesting Research on Transition States

Oh I didn't realize that. But wow, it is a pretty interesting paper.
by GunvantChaudhari 2F
Fri Feb 26, 2016 10:37 am
Forum: *Organic Reaction Mechanisms in General
Topic: Interesting Research on Transition States
Replies: 2
Views: 397

Interesting Research on Transition States

I just happened to come across this article, but it applies pretty well to what we are learning right now: http://www.scientificamerican.com/article/for-the-first-time-chemists-measure-the-energy-of-a-chemical-reaction-s-transition-state/ Essentially chemists shined a laser at a conformation of acet...
by GunvantChaudhari 2F
Sat Feb 20, 2016 4:19 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Intermediates and Free Energy
Replies: 1
Views: 367

Re: Intermediates and Free Energy

I think you are essentially correct. The transition state has different partial bonds for a catalyzed reaction than for an uncatalyzed one.
by GunvantChaudhari 2F
Sat Feb 20, 2016 4:13 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady State Reaction
Replies: 2
Views: 468

Re: Steady State Reaction

Steady state approach assumes that the intermediate remains at a constant concentration, so all the additions and subtractions of the intermediate sum up to zero. If you want more information, it is explained in the textbook in 15.8.
by GunvantChaudhari 2F
Sat Feb 20, 2016 4:11 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: questions 15.67 and 15.69
Replies: 1
Views: 449

Re: questions 15.67 and 15.69

The formula that the solutions manual uses is simply the division of the rate constant when the reaction is catalyzed by the rate constant when the reaction is uncatalyzed. You don't have to use that formula. You can just find the k's separately and divide them to find the ratio.
by GunvantChaudhari 2F
Sat Feb 20, 2016 2:57 pm
Forum: Zero Order Reactions
Topic: Not zero, first, or second?
Replies: 4
Views: 627

Re: Not zero, first, or second?

Yes there is such a thing as a half order reaction. For examples of how a reaction mechanism would lead to a half order reaction, see examples 2 and 3 here: http://www.science.uwaterloo.ca/~cchieh/cact/c123/ratemech.html
by GunvantChaudhari 2F
Sun Jan 24, 2016 11:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy in Biology
Replies: 1
Views: 315

Re: Gibbs Free Energy in Biology

Well what causes biological reactions to occur at constant temperature and pressure is largely due to the fact that these reactions are aqueous (liquids don't expand or pressurize to a great extent) and that the human body regulates its temperature to a fairly narrow temperature range. I think what ...
by GunvantChaudhari 2F
Sun Jan 24, 2016 11:29 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Reversible vs Irreversible Reactions
Replies: 1
Views: 318

Re: Reversible vs Irreversible Reactions

I agree it can be tough at times to tell the difference between irreversible and reversible and to find the correct equation. In general, what I have found that helps is equations for reversible things are many times the ones that have the "ln". Also, the calculations and equations for ent...
by GunvantChaudhari 2F
Thu Jan 21, 2016 1:28 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.35B
Replies: 1
Views: 395

Re: 8.35B

Hmm I just tried this problem and it worked for me according to the solution manual. I got 8.90 g/cm^3. Here's how I did it: Density = m / v D = (63.546 * 4) / ( (6.02*10^23) * (128*10^(-12)*2*sqrt(2))^3 ) * 1/100^3 So this is the mass and volume of a mole of copper atoms. There are 4 atoms in face ...
by GunvantChaudhari 2F
Thu Jan 21, 2016 12:47 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Example 8.31
Replies: 1
Views: 296

Re: Textbook Example 8.31

A bond enthalpy is defined as the mean energy required to break a bond when the molecule is in the gas phase . Therefore, you have to essentially vaporize the liquid (and solid) molecules, which you do so by adding in the heat of vaporization (and the heat of fusion if solid). The similar concept ap...
by GunvantChaudhari 2F
Thu Jan 21, 2016 12:29 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: qrev
Replies: 1
Views: 428

Re: qrev

qrev refers to the heat transfer during a reversible process. In other words that equation can only be used when you are dealing with reversible expansions or compressions.
by GunvantChaudhari 2F
Tue Jan 05, 2016 5:43 pm
Forum: Phase Changes & Related Calculations
Topic: ammonium nitrate dissolution
Replies: 2
Views: 702

Re: ammonium nitrate dissolution

I just wanted to add that how dissolving works is that it takes energy to break the bonds in the solute and energy is released when the solute ions are surrounded by the solvent to form a kind of a shell. For Ammonium Nitrate, it just so happens that more energy is required to break the bonds in the...
by GunvantChaudhari 2F
Sun Dec 06, 2015 3:09 am
Forum: Empirical & Molecular Formulas
Topic: Fall 2014 Final Exam Q1A
Replies: 1
Views: 376

Re: Fall 2014 Final Exam Q1A

When we first learned about how to find empirical formulas, we did go through finding the mass% and setting the total mass to a 100g. However, this step is not necessary, as we are simply dealing with ratios. 2:4:6:8 is the same as 10:20:30:40, even though the latter one adds up to 100. As we are en...
by GunvantChaudhari 2F
Sun Dec 06, 2015 2:56 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: ICE Tables
Replies: 2
Views: 549

Re: ICE Tables

When the K value associated with the equation for the reaction is less than 10^-4, we can assume that x is small enough to not affect our end result to a significant extent.
by GunvantChaudhari 2F
Sun Dec 06, 2015 2:54 am
Forum: Bond Lengths & Energies
Topic: Bond enthalpy in 2013 final #3E
Replies: 1
Views: 712

Re: Bond enthalpy in 2013 final #3E

In general, enthalpy is the amount of heat released (or absorbed) when a chemical reaction occurs. The bond enthalpy refers to the amount of heat (energy) that is required to break a bond. The stronger the bond, the more heat that is required to break it, so we are looking for the molecule with the ...
by GunvantChaudhari 2F
Sun Dec 06, 2015 2:44 am
Forum: *Titrations & Titration Calculations
Topic: Fall Final 2010 Question 7F
Replies: 4
Views: 602

Re: Fall Final 2010 Question 7F

I think it helps if we refer to this equation, the neutralization equation involved in the titration: NaOH + HC2H3O2 => NaC2H3O2 + H2O We know from earlier in question 7 that you need 25 mL of NaOH to fully neutralize the 25 mL of acetic acid. However, this means that when you reach the equivalence ...
by GunvantChaudhari 2F
Sun Dec 06, 2015 2:08 am
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: buffer with new pH problem 2014 final
Replies: 1
Views: 448

Re: buffer with new pH problem 2014 final

So you basically have two reactions at work here: (1) HC2H3O2 + H2O <=> H3O(+) + C2H3O2(-) (2) NaOH + HC2H3O2 => H2O + Na(+) + C2H3O2(-) Disregarding (2) for a second, you could easily calculate the ph of the solution at equilibrium using the Henderson-Hasselback equation, plugging in the concentrat...
by GunvantChaudhari 2F
Sun Dec 06, 2015 1:27 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Compound Drawing
Replies: 4
Views: 957

Re: Chelating Compound Drawing

I think this picture does a good job of showing the binding. In general, if you see OH (or O-), SH (or S-), or N in a molecule, you can guess that the molecule can form a coordinate bond there. http://image.slidesharecdn.com/toxicitiesandmanag-ofpoisoningsheavymetals-130512014931-phpapp02/95/toxicit...
by GunvantChaudhari 2F
Sun Nov 29, 2015 11:55 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Video: Molecular Orbital Theory
Replies: 1
Views: 329

Video: Molecular Orbital Theory

Here's a video that I made about general molecular orbital theory. I hope it helps!
by GunvantChaudhari 2F
Thu Oct 22, 2015 11:09 pm
Forum: Electronegativity
Topic: Bonds
Replies: 3
Views: 566

Re: Bonds

Of those three compounds, CF4 will have the strongest CX bond because this bond is the shortest. The internuclear distance between the carbon atom and the fluorine atom is smaller than that between the carbon atom and the halogen atom in CCl4 and CBr4 because the atomic radius of the fluorine atom i...
by GunvantChaudhari 2F
Sun Oct 18, 2015 12:10 pm
Forum: Resonance Structures
Topic: Significance of Resonance Structures
Replies: 1
Views: 434

Re: Significance of Resonance Structures

A few things resonance structures help reveal about molecules are relative lengths of the bonds (i.e. Carbon to carbon bonds in benzene have a length between C-C and C=C), the energy of the bond (something that is dependent on the length of the bonds), and the distribution of charge in the molecule ...
by GunvantChaudhari 2F
Sun Oct 18, 2015 11:58 am
Forum: Resonance Structures
Topic: Stop when formal charge of central atom is zero?
Replies: 1
Views: 403

Re: Stop when formal charge of central atom is zero?

Hi Alyssa, In general, there are three basic rules to determine the most stable structure for a molecule (although I bet there are exceptions to this like there are for everything): - Lowest magnitude of formal charge - More electronegative atoms should have negative formal charges - Adjacent atoms ...
by GunvantChaudhari 2F
Sun Oct 11, 2015 2:09 pm
Forum: Lewis Structures
Topic: BF_3 Lewis Structure
Replies: 1
Views: 303

Re: BF_3 Lewis Structure

This website was very helpful to me in explaining the odd nature of boron trifluoride (Exception 2):
http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/Lewis_Theory_of_Bonding/Violations_of_the_Octet_Rule

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