Search found 18 matches

by Megan White 2C
Sun Feb 22, 2015 7:21 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Determining Intermediates/Catalysts - #14.47
Replies: 4
Views: 859

Determining Intermediates/Catalysts - #14.47

Hello All! In Lecture on Friday, Dr. Lavelle introduced the topic of catalysts, and within his explanation, he mentioned that catalysts are involved in chemical RXNs, but they are neither reactants nor products, nor are they PRODUCED in the chemical RXN at hand. With all of that in mind, in working ...
by Megan White 2C
Thu Feb 05, 2015 7:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing a Half Reaction from a word problem (Homework #13.17
Replies: 4
Views: 1961

Re: Writing a Half Reaction from a word problem (Homework #1

I have an additional question for problem 13.17: Where does the H+ ion come from on the CATHODE side of the cell diagram that we are told to draw? When I was drawing my diagram, I came up with: Pt(s)| Fe 2+, Fe 3+|| MnO4-, Mn 2+| Pt(s) But the answer in the back of the book reads: Pt(s)| Fe 2+, Fe 3...
by Megan White 2C
Thu Feb 05, 2015 7:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrochemistry and reverse reactions
Replies: 3
Views: 23931

Re: Electrochemistry and reverse reactions

Hi Viridiana! Upon looking up the standard REDUCTION potentials in the index when dealing with an oxidation half reaction, you have two options: #1: You can keep the value in the back of the book (without switching the sign) #2: Or, you can switch the sign. In using the formula for the cell potentia...
by Megan White 2C
Wed Jan 28, 2015 6:52 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: delta U within calorimeter
Replies: 2
Views: 1462

Re: delta U within calorimeter

Hi Yasmine! To start, if you are dealing with an isolated system, delta U is always going to equal 0. Essentially, no heat is coming in or out of the system, nor is the volume/pressure of the system changing, so there would be no change in the internal heat (U) of an isolated system. This is the fir...
by Megan White 2C
Mon Dec 01, 2014 6:06 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: workbook problem
Replies: 2
Views: 543

Re: workbook problem

Hi Hannah! Speeding up the rate of a reaction (i.e. with a catalyst) will make product formation happen FASTER, but that does not mean that MORE PRODUCTS will be made in the process. Speeding up the reaction will form the same amount of products as the reaction would form without the aid of a cataly...
by Megan White 2C
Sun Nov 30, 2014 7:48 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and HW problem 10.13
Replies: 1
Views: 384

Re: Q and HW problem 10.13

Hi Kiana! When solving for Q for a reaction containing molecules in various states, only molecules in the GASEOUS and AQUEOUS states are included in the equation. SOLIDS and LIQUIDS are NOT included in the equation for Q (or for K!!) because the concentrations of substances in these "pure"...
by Megan White 2C
Sun Nov 30, 2014 7:42 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 2012 quiz 3 prep #1
Replies: 5
Views: 1229

Re: 2012 quiz 3 prep #1

Thank you so much, Eduardo! That clears it all up!
by Megan White 2C
Sat Nov 29, 2014 10:10 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 2012 quiz 3 prep #1
Replies: 5
Views: 1229

Re: 2012 quiz 3 prep #1

Unfortunately, I can't help with clearing up some of this confusion (I am having trouble with this problem as well), but I do have an additional question to add to this stream: I'm having trouble figuring out the order of the naming process for the compound. Why is chromium(II) listed after bis(ethy...
by Megan White 2C
Mon Nov 24, 2014 8:30 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Cubic Equations
Replies: 8
Views: 1310

Re: Cubic Equations

Thanks so much, you guys! Makes a lot more sense now. Double advice is always welcome! :)
by Megan White 2C
Thu Nov 20, 2014 7:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Cubic Equations
Replies: 8
Views: 1310

Cubic Equations

Hi All! In lecture yesterday, Professor Lavelle went over how to solve CUBIC chemical equations. I understood all of the steps until the approximating of reactant values based on the small equilibrium constant. Why is it that we are to assume that the (X) value is = 0 when the equilibrium constant i...
by Megan White 2C
Thu Nov 20, 2014 7:46 pm
Forum: Naming
Topic: 16.29 part d
Replies: 3
Views: 401

Re: 16.29 part d

Hi! For part D, (diaqua) is translated into (OH2)2 to show that the (O) atom rather than the (H) atom is the atom that is involved in forming the bond with the Fe atom. The atom within a molecule that is participating in the "binding" action with another atom/molecule within a coordination...
by Megan White 2C
Wed Nov 05, 2014 9:00 am
Forum: Lewis Structures
Topic: Calculating Number of Electrons
Replies: 2
Views: 356

Re: Calculating Number of Electrons

Hi Vivien!

That is correct. A positively charged ion is indicative of a greater amount of protons within an atom than electrons. Removing electrons (negatively charged particles) will make a neutral atom positive due to the resulting greater amount of protons left over.

Hope this helps!
by Megan White 2C
Wed Nov 05, 2014 6:16 am
Forum: Dipole Moments
Topic: VSEPR/Dipole Moments
Replies: 1
Views: 303

Re: VSEPR/Dipole Moments

Hi Virginia! That is correct. If all of the atoms surrounding the central atom in the Lewis Structure are the the same (i.e. all the same element) and distributed symmetrically about the central atom, then it is NON-POLAR. For example, CH4 is NON-POLAR, while CH3Cl is POLAR. Even though both Lewis S...
by Megan White 2C
Tue Nov 04, 2014 10:02 pm
Forum: Electronegativity
Topic: Differences in Electronegativity between Groups and Periods
Replies: 1
Views: 539

Re: Differences in Electronegativity between Groups and Peri

Hi Crystal! By definition, electronegativity is an atomic characteristic representing the tendency/power of an atom to attract electrons. Atoms closest to the nobel gases (i.e. the halogens) only need one more electron to complete their octet. Therefore, atoms in the 17th group of the periodic table...
by Megan White 2C
Mon Nov 03, 2014 5:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 3.1 Must/May/Cannot have LP on Central Atom
Replies: 3
Views: 536

Re: 3.1 Must/May/Cannot have LP on Central Atom

Hey Madison! The amount of lone pairs (if any) and bonds (single, double, triple) around a central atom in a Lewis Structure depends on the other atoms that are involved in the molecule. There is no way to tell if an atom will have lone pairs/bonds until you are informed of the other atoms that are ...
by Megan White 2C
Tue Oct 28, 2014 11:14 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Numbers
Replies: 2
Views: 497

Re: Formal Charge Numbers

A single bond is technically 2 SHARED atoms - so the totally numbered of shared atoms per single bond (represented by 'S' in the formal charge equation) is in fact symbolic of 2 atoms, not 1!.

Hope this helps!
by Megan White 2C
Wed Oct 22, 2014 6:56 pm
Forum: Lewis Structures
Topic: Expanded Octets
Replies: 3
Views: 631

Expanded Octets

Hello all! Today in lecture, we continued our discussion of Lewis Structures, and in particular, how to draw more stable lewis structures using double bonds. One of the examples we worked through was the Lewis Structure for a sulfate ion --> SO4 (2-). Professor Lavelle indicated in his drawn out exa...

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