Search found 22 matches

by Melanie_Wong_1K
Thu Mar 09, 2017 10:33 pm
Forum: *Cycloalkanes
Topic: "iso" naming
Replies: 4
Views: 815

Re: "iso" naming

For question 1.16 in the organic chemistry textbook, why is the answer 2-isopropyl-1,1-dimethylcyclopentane and not 1,1-dimethyl-2-isopropylcyclopentane? Following the alphabetical ordering rule This one is tricky, so you take iso- into account when alphabetizing the substituents, but not di-. Ther...
by Melanie_Wong_1K
Tue Mar 07, 2017 2:57 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Naming of molecules
Replies: 2
Views: 272

Re: Naming of molecules

I think it's just one or the other.
by Melanie_Wong_1K
Mon Feb 27, 2017 5:34 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Determining Where Hydrogen Bonds
Replies: 5
Views: 582

Re: Determining Where Hydrogen Bonds

The curved arrows are meant to model which bonds are broken or which lone pairs break off, they show which atom the electrons are moving to. An arrow with a normal head means two electrons move from the bond/lone pair while an arrow with half a head means only one electron moves.
by Melanie_Wong_1K
Tue Feb 21, 2017 2:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 2 Winter 2017
Replies: 160
Views: 14869

Re: Quiz 2 Winter 2017

How is question one done from quiz 2? When you balance the reaction, you get 2 mol N2O5, so you multiply the rate of decomposition of N2O5, 2.89, by 2 to get the rate of formation of NO2. So, this would be 2(2.89)= 5.78 (mol NO2)⋅L–1⋅s–1 Does this mean the coefficient in front of the reactants does...
by Melanie_Wong_1K
Sun Feb 19, 2017 10:53 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 891090

Re: Post All Chemistry Jokes Here

If you're not part of the solution, you're part of the precipitate.
by Melanie_Wong_1K
Sat Feb 11, 2017 9:12 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Winter 2013 Midterm #8B
Replies: 2
Views: 284

Re: Winter 2013 Midterm #8B

This question actually concerns both #8b and 7 of the 2013 Midterm. When you're using the Nerst Equation, how do you find n? The moles aren't given in either of the problems but the answer to #7 says n=10 and for #8b n=2. They don't seem to relate to the amount of moles in the chemical equations eit...
by Melanie_Wong_1K
Fri Jan 20, 2017 5:04 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Positional Entropy or Thermal Entropy?
Replies: 1
Views: 366

Re: Positional Entropy or Thermal Entropy?

I believe this equation is used to find positional/residual entropy in an isothermal system that has a reversible reaction, meaning no energy is transferred as heat and the reaction can go backwards.
by Melanie_Wong_1K
Wed Jan 18, 2017 4:42 pm
Forum: Phase Changes & Related Calculations
Topic: New to Lavelle: Formula Sheets? [ENDORSED]
Replies: 3
Views: 391

Re: New to Lavelle: Formula Sheets? [ENDORSED]

You're given a formula sheet and periodic table for each quiz, midterm, and the final. It's usually a page on the back that you can rip off to use. But it doesn't look exactly like the laminated sheet we were given with the course reader. The periodic table elements have more specific masses and the...
by Melanie_Wong_1K
Thu Jan 12, 2017 10:43 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy of Formation Question
Replies: 3
Views: 302

Re: Standard Enthalpy of Formation Question

The standard enthalpy of formation is related to standard reaction enthalpies . Since reactants and products can be in different states and reactions can occur at different pressures, the enthalpy can change. The standard reaction enthalpies found on pg. 17 of the course reader allow for uniformity ...
by Melanie_Wong_1K
Fri Nov 25, 2016 2:58 pm
Forum: Conjugate Acids & Bases
Topic: is h3o related to oh-
Replies: 2
Views: 1634

Re: is h3o related to oh-

Yep, H30+ and OH- are formed from H20 during autoprotolysis. One of the water atoms steals an oxygen from another water atom. The reaction is called autoprotolysis because the molecules are the same, they just transfer protons.
by Melanie_Wong_1K
Mon Nov 14, 2016 10:36 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How do you find the number of attachment possible?
Replies: 3
Views: 450

Re: How do you find the number of attachment possible?

Ethylenediamine (en) is a bidentate which means it has 2 attachment sites. Diethylenetriamine (dien) is a tridentate which means it has 3 attachment sites. In the table on page 117 of the course reader, I believe every other ligand is a monodentate which means it has one attachment site except excep...
by Melanie_Wong_1K
Mon Nov 14, 2016 9:19 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Wrting the Chemical Formula for Coordination Compounds
Replies: 3
Views: 1223

Re: Wrting the Chemical Formula for Coordination Compounds

download.png Actually there is a rule. (Here's the URL in case the picture doesn't load, this site is super helpful for naming coordinate compounds: )
by Melanie_Wong_1K
Thu Nov 10, 2016 1:42 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Drawing MO diagrams
Replies: 2
Views: 344

Re: Drawing MO diagrams

Remember that MO diagrams are supposed to show resonance structures, molecules with unpaired elections, and information about the bond energies which all depend on valence electrons and how they bond with other atoms. The important information should be in which electrons are left unpaired and drawi...
by Melanie_Wong_1K
Tue Nov 01, 2016 5:16 pm
Forum: Hybridization
Topic: Hybridization
Replies: 2
Views: 283

Re: Hybridization

The hybridization number depends on the number of bonds/valence electrons attached to the given atom. You just have to remember that double and triple bonds count as one hybridized bond. So a carbon with 4 single bonds will have a hybridization of sp^3 while a carbon with two single bonds and a doub...
by Melanie_Wong_1K
Thu Oct 27, 2016 4:26 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 891090

Re: Post All Chemistry Jokes Here

I'm so tired when I'm chemistry-ing because chem is trying.
by Melanie_Wong_1K
Thu Oct 27, 2016 4:14 pm
Forum: Octet Exceptions
Topic: Half Full d^5 and Full d^10 Subshells
Replies: 4
Views: 610

Re: Half Full d^5 and Full d^10 Subshells

There would only be an exception for the Co^2- ion which acts like Cu. It's electron configuration would then be [Ar] 3d^10 4s^1.
by Melanie_Wong_1K
Wed Oct 19, 2016 11:28 am
Forum: Resonance Structures
Topic: Formal Charge [ENDORSED]
Replies: 3
Views: 435

Re: Formal Charge [ENDORSED]

Third question: Sulfur can hold more electrons in it's valence shell because it borrows space from a d-orbital. When the electrons don't fit in the p-orbital anymore, it just adds the electrons to the next available orbital (3d). However, you can only do this if the atom is in the 3rd period or lowe...
by Melanie_Wong_1K
Fri Oct 14, 2016 4:24 pm
Forum: Ionic & Covalent Bonds
Topic: Ionization Energy
Replies: 7
Views: 716

Re: Ionization Energy

Use the periodic table. Remember that right side and upper elements have higher ionization energies, so the upper right hand corner of the table has elements with the highest ionization energies and the lower left hand corner has the lowest. So if you're comparing two, say Sulfur and Fluorine, Sulfu...
by Melanie_Wong_1K
Wed Oct 05, 2016 10:41 am
Forum: Properties of Electrons
Topic: Atomic Spectra Requirements [ENDORSED]
Replies: 3
Views: 385

Re: Atomic Spectra Requirements [ENDORSED]

I think it's better to know the general ranges of the Infrared, Visible, and Ultraviolet regions of the electromagnetic spectrum just because those are used the most. Here are all the ranges just in case: radio waves - 10 cm microwaves - 1 mm infrared - greater than 800 nm, about 1000 nm visible - 4...
by Melanie_Wong_1K
Mon Sep 26, 2016 10:00 pm
Forum: Properties of Light
Topic: Wavelength and Energy
Replies: 3
Views: 823

Re: Wavelength and Energy

For 1.23 remember that wavelength=speed of light constant/frequency, and frequency = Energy/Planck's constant, so if Y is wavelength (because I can't figure out how to type lambda) Y=c/v and v=E/h. So you just have to set it up as Y=hc/E and subsitute 6.626x10^(-34) for h, 3.00x10^(8) for c, and plu...

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