Search found 31 matches

by ConnieDo3I
Fri Mar 11, 2016 2:26 am
Forum: *Cyclopentanes
Topic: Torsional strain V steric strain
Replies: 2
Views: 920

Re: Torsional strain V steric strain

Torsional strain has to do with a force that opposes a molecule's ability to rotate, whereas steric strain has to do with molecules/atoms occupying the same space, causing the charges on the molecules/atoms to interact unfavorably. Torsional strain appears in eclipsed conformations because charged p...
by ConnieDo3I
Fri Mar 11, 2016 2:17 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Cis and Trans Placement
Replies: 1
Views: 315

Re: Cis and Trans Placement

"Cis" and "trans" typically appear when the molecule has a double bond or a ring. Those are situations when substituents can "be on the same side" or "be on the opposite side" of a molecule.

Hope this helps!
by ConnieDo3I
Sat Mar 05, 2016 12:55 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Possible conformations
Replies: 1
Views: 317

Re: Possible conformations

I think the main thing that makes some conformations more stable than others are the electrostatic forces that interact. Generally, the conformations that are more stable remain the "more stable" conformation at different temperatures, but at lower temperatures, there is more of the "...
by ConnieDo3I
Sat Mar 05, 2016 12:50 am
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Envelope conformation
Replies: 1
Views: 233

Re: Envelope conformation

By that one carbon going out of the plane, some of the C-H bonds attached to the carbons adjacent to the carbon that went out of plane are staggered. I believe Professor Lavelle said we did not need to go into detail as to why there are still 2 pairs of eclipsed C-H bonds.

Hope this helps!
by ConnieDo3I
Sat Feb 27, 2016 5:52 pm
Forum: *Electrophiles
Topic: Nucleophiles
Replies: 5
Views: 548

Re: Nucleophiles

I think that elements in the same group (column) would have the same number of valence electrons and, therefore, the same number of lone pairs, if any.
by ConnieDo3I
Fri Feb 26, 2016 2:02 pm
Forum: *Electrophiles
Topic: Nucleophiles
Replies: 5
Views: 548

Re: Nucleophiles

I think you can also count the number of lone pairs. The more lone pairs, the stronger the nucleophile (because it has more electrons).

Hope this helps!
by ConnieDo3I
Fri Feb 26, 2016 2:01 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: effect of Temperature
Replies: 1
Views: 268

Re: effect of Temperature

It's because the forward reaction has the higher activation barrier. The rate constant of the reaction with the higher activation barrier will increase more than that of the reaction with the lower energy barrier when the temperature is raised.

Hope this helps!
by ConnieDo3I
Fri Feb 19, 2016 2:24 am
Forum: First Order Reactions
Topic: First Order Reactions
Replies: 1
Views: 276

Re: First Order Reactions

Most likely not, but I think decay reactions are a very common example of first-order reactions.

Hope this helps!
by ConnieDo3I
Fri Feb 19, 2016 2:21 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Reverse reaction of k
Replies: 2
Views: 463

Re: Reverse reaction of k

Since K = k/k', and K is unit-less, k' (reverse reaction) should have the same units as k (forward reaction), if that was what you were asking.

Hope this helps!
by ConnieDo3I
Fri Feb 12, 2016 8:20 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: How to separate solids in a cell diagram
Replies: 3
Views: 454

Re: How to separate solids in a cell diagram

You would separate them with a line because Pt is an inert electrode. It is not involved with the reaction.

Hope this helps!
by ConnieDo3I
Sun Feb 07, 2016 2:07 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Units in Nernst Equation
Replies: 2
Views: 400

Re: Units in Nernst Equation

If the concern is about the units within the natural log, ln, I think you don't have to worry about that. Q is a unit-less dimension, I believe.

Hope this helps!
by ConnieDo3I
Sun Feb 07, 2016 2:03 pm
Forum: Balancing Redox Reactions
Topic: Working with Single Diatomic Molecules (14.5B)
Replies: 2
Views: 390

Re: Working with Single Diatomic Molecules (14.5B)

To expand on the previous answer and apply it to your specific problem number, I used Br2 in both of my written half reactions. (also, since Br2 is a liquid and not an aqueous solution, I don't think you can split the atoms).

Hope this helps!
by ConnieDo3I
Sat Jan 30, 2016 10:29 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Delta G subscript r
Replies: 2
Views: 1159

Re: Delta G subscript r

It shouldn't change the resulting value because adding the subscript "r" to n (nr) just makes "n" a pure number instead of being "n moles". Therefore, the resulting Gr would have units J (or kJ) / mol.

Hope this helps!
by ConnieDo3I
Sat Jan 23, 2016 9:09 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Properties of an Irreversible Reaction
Replies: 1
Views: 284

Properties of an Irreversible Reaction

I was doing question 9.47, and the solution says that ∆U = 0 in part b, the irreversible reaction. I was wondering if/why ∆U=0 is a property of an irreversible reaction. Thanks!
by ConnieDo3I
Sat Jan 23, 2016 6:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.57 Clarification
Replies: 2
Views: 323

Re: 8.57 Clarification

For this problem, they give you the ∆H° c for each of the compounds involved in the final equation. This means that they gave you the enthalpy of combustion for each compound, which means the heat released when the compound undergoes combustion. To get the reaction that the book gives you, you have ...
by ConnieDo3I
Fri Jan 15, 2016 5:07 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Constant Volume & Internal Energy
Replies: 1
Views: 228

Re: Constant Volume & Internal Energy

qv is heat with volume held constant.

We are given the equation delta(U) = q + w, where w = -Pdelta(V).

If the change in volume is 0 (if delta(V) is 0), then we would have delta(U) = q.

Hope this helps!
by ConnieDo3I
Sun Jan 10, 2016 5:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy
Replies: 1
Views: 201

Re: Bond Enthalpy

You can write out the chemical equation to see the reactants and the products. From there, you can decipher which bonds need to be separated and which need to be formed in order to get the product molecules from the reactant molecules. Technically you don't need to draw out the Lewis structures if y...
by ConnieDo3I
Wed Dec 09, 2015 10:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Regarding Quiz Corrections
Replies: 1
Views: 2391

Regarding Quiz Corrections

Good evening, Dr. Lavelle

I hope I'm not too late with this inquiry! I've been waiting for an email response for a while from my TA, but I was wondering, if we think there has been a mistake in our quiz score (for me, quiz 3), could it still be fixed?

Thank you in advance!
by ConnieDo3I
Fri Dec 04, 2015 3:42 am
Forum: Lewis Acids & Bases
Topic: Increasing Strength of Acids (Electron Withdrawal Abilities)
Replies: 1
Views: 312

Re: Increasing Strength of Acids (Electron Withdrawal Abilit

I think that the acid with F's attached is stronger than the acid with Cl's attached because F is more electronegative than Cl. Recall that a Lewis acid is an electron pair acceptor. Because F is more electronegative, it's able to "withdraw (electrons from other molecules)" or "accept...
by ConnieDo3I
Sun Nov 29, 2015 8:30 pm
Forum: Lewis Acids & Bases
Topic: Acid & Bases
Replies: 2
Views: 569

Re: Acid & Bases

I don't think so. An acid/base is strong or weak depending on its molecular structure and how well it dissociates in water, not on any reaction it may partake in.

Hope this helps!
by ConnieDo3I
Sat Nov 28, 2015 11:07 pm
Forum: Dipole Moments
Topic: Polarity of Molecules
Replies: 2
Views: 553

Re: Polarity of Molecules

I'm not completely sure, but if there's a lone pair, I don't think the molecule would be symmetric. I guess, then, you could infer that molecules with lone pairs are polar. (I have yet to find an example to prove otherwise.) [Regarding polarity in general: It might help to draw out the structure of ...
by ConnieDo3I
Mon Nov 23, 2015 12:46 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining coordination number
Replies: 2
Views: 580

Re: Determining coordination number

Hi!
I believe the coordination number is determined by the number of bonds attached to the transition metal.
by ConnieDo3I
Sun Nov 15, 2015 2:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Kp?
Replies: 1
Views: 295

Re: Calculating Kp?

Hi,
I'm assuming you would use the units the problem gives you, so it's probably not a big issue.
by ConnieDo3I
Sun Nov 08, 2015 4:34 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 11.29
Replies: 2
Views: 437

Re: 11.29

Hey! To find out if a reaction tends towards products or tends towards reactants, we would need to compare the reaction quotient (Q) with the equilibrium constant (K). In this case, K = 4.0 x 10^-31 (but to find this, we would have to use methods described in section 11.3, which we didn't learn). So...
by ConnieDo3I
Sun Nov 08, 2015 4:27 pm
Forum: Naming
Topic: Use of Parenthesis
Replies: 1
Views: 317

Re: Use of Parenthesis

Hey!
I'm not 100% sure but I think it's just to clarify that the prefix "di-" belongs only to "aqua."
Hope this helps!
by ConnieDo3I
Sun Nov 01, 2015 3:16 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbitals w/Nuclear charges <8
Replies: 1
Views: 191

Re: Molecular Orbitals w/Nuclear charges <8

Hey!

If one of the atoms in the diatomic molecule has a nuclear charge of less than 8, the σ2pz M.O. would be at a higher energy than the π2px and π2py M.O.s

Hope this helps!
by ConnieDo3I
Sun Nov 01, 2015 3:12 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Equations
Replies: 2
Views: 476

Re: Balancing Equations

Hey! After you balance the equation, each element needs to have the same number of moles on each side. So you would just multiply each element by the coefficient that is in front of the molecule. If the element has a subscript, multiply that in too. Ex: 2 mol Cl 2 would be the same as having 4 mol C...
by ConnieDo3I
Sun Oct 25, 2015 9:39 pm
Forum: Lewis Structures
Topic: HW 3.89
Replies: 2
Views: 210

Re: HW 3.89

Hey! You should draw the Lewis structure of the molecules first so you can see whether the bond between the two atoms asked for is single, double, or triple. Then, depending on that, add the according radii in the table. For example, if you had a double bond between C and O, you would add the radius...
by ConnieDo3I
Sun Oct 18, 2015 11:01 pm
Forum: Einstein Equation
Topic: HW 1.25 (b)
Replies: 2
Views: 524

Re: HW 1.25 (b)

Hey! So according to the solutions manual, E = (5.00 x 10^-3 g Na / 22.99 g x mol^(-1)) x (6.022x10^23 atoms x mol^(-1)) x (3.37x10^(-19) J x atom^(-1)) = 44.1 J If you follow the equation, the "atoms" unit should cancel out smoothly. The following is the equation with only the units. It's...
by ConnieDo3I
Sat Oct 10, 2015 4:14 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative sign in the Schrodinger equation
Replies: 3
Views: 856

Re: Negative sign in the Schrodinger equation

Hey! If you're referring to E_{n}=\frac{-hR}{n^{2}} , the purpose of the negative sign correlates to the equation ∆E = E final - E initial . The negative sign allows you to see that an electron undergoes a negative energy change (∆E) when it goes from a higher energy level (n) to a lower energy leve...
by ConnieDo3I
Sun Oct 04, 2015 2:53 pm
Forum: Molarity, Solutions, Dilutions
Topic: G19
Replies: 1
Views: 668

Re: G19

Hey! For convenience, I'll copy the problem here. "(a) A sample of 1.345 M K2SO4(aq) of volume 12.56 mL is diluted to 250.0 mL. What is the molar concentration of K2SO4 in the diluted solution? (b) A sample of 0.366 M HCl(aq) of volume 25.00 mL is drawn from a reagent bottle with a pipet. The s...

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