Search found 26 matches
- Thu Mar 16, 2017 9:56 am
- Forum: *Alkenes
- Topic: Alkenes and Functional Groups
- Replies: 4
- Views: 1896
Re: Alkenes and Functional Groups
To add on, the double bond from the aldehyde does not need to be explicitly written because it is implied that it is there (since it corresponds to the functional group) when you add the suffix -al to the end of pentane (after dropping the e of course).
- Thu Mar 09, 2017 9:40 am
- Forum: Administrative Questions and Class Announcements
- Topic: Quiz 3 Winter 2017
- Replies: 183
- Views: 29783
Re: Quiz 3 Winter 2017
For the quiz 3 preparation, why does electrophilic addition have 2 intermediates? Graphically, isn't there only 1?
- Thu Mar 02, 2017 10:15 am
- Forum: *Alkanes
- Topic: Branched vs. Unbranched
- Replies: 2
- Views: 1101
Re: Branched vs. Unbranched
I'm pretty sure you can draw any structure, branched or unbranched, otherwise, he would be explicit about it. As long as you have the correct number of carbons and hydrogens, you should get full points.
- Thu Feb 23, 2017 9:53 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells
- Replies: 4
- Views: 889
Re: Galvanic Cells
Also,just know that the metals should be transition metals when using them as electrodes.
- Wed Feb 15, 2017 10:37 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 11
- Views: 1714
Re: Cell Diagram
I think that there is a specific order in which you should have them inside of the diagram. The aqueous solution should be closest to the salt bridge, which is represented by "II". Then, I believe that the liquid goes after that and then its gas. Solids are the last ones.
- Thu Feb 09, 2017 10:05 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Course Reader Example
- Replies: 4
- Views: 914
Re: Course Reader Example
It is saying that it does occur at 25 degrees celsius & 1 atm, but very slowly.
- Wed Feb 01, 2017 1:23 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Prep quiz 1 #3
- Replies: 3
- Views: 798
Re: Prep quiz 1 #3
For problem 3 you use w = -nRTln(V2/V1) because the problem states that the reaction is "reversible". If you go back to page 33 in the course reader, it explains which equations of w to use depending if the reaction is reversible or irreversible. Also, the problem tells you that pressure a...
- Thu Jan 26, 2017 11:14 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Formulas to know
- Replies: 3
- Views: 1011
Re: Formulas to know
If you look in the course reader at what we have learned about so far, you can assume that most formulas will be needed. Also, check the formula sheet in the course reader (pg. 125) which is the one we'll be getting for the quiz. You can check to see if there are any formulas that are not there that...
- Wed Jan 18, 2017 1:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: Calculating Enthalpy [ENDORSED]
- Replies: 4
- Views: 1083
Re: Calculating Enthalpy [ENDORSED]
Yes, for that sample problem, the reaction enthalpy is given as -555.38 kJ, but in order to get the standard enthalpy of formation (the same as trying to get the enthalpy of one mole)of graphite, you divide by 2 as stated above.
- Wed Jan 11, 2017 9:10 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Stable forms for Standard Enthalpies of Formation
- Replies: 2
- Views: 492
Re: Stable forms for Standard Enthalpies of Formation
I think that Dr. Lavelle was hinting at the fact that the stable form of every element should be known because he was talking about how oxygen's stable form is O2 gas and he went over other elements as a review. So in that case, I would say yes, you should memorize, it'll make things easier.
- Sat Dec 03, 2016 11:11 am
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: When to disregard -x in equilibrium formula?
- Replies: 2
- Views: 754
Re: When to disregard -x in equilibrium formula?
I think that you can assume x=0 when your Kb,Kb, or Kc value is less than 10^-5?
- Sun Nov 27, 2016 7:56 pm
- Forum: Bronsted Acids & Bases
- Topic: Distinction between Bronsted and Lewis
- Replies: 2
- Views: 735
Re: Distinction between Bronsted and Lewis
Bronsted acids and bases only deal with protons--acids lose protons whereas bases gain protons. Lewis acids and bases deal with electrons--acids accept electrons and bases donate electrons.
- Wed Nov 16, 2016 8:50 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Electron configuration of molecules
- Replies: 1
- Views: 870
Re: Electron configuration of molecules
It might depend on your TA, but in the course reader, there is an example where you have: (σ2s)^2(σ*2s)^2(σ2pz)^2(π2p)^4(π*2p)^2. It's on page 109.
- Fri Nov 11, 2016 1:27 pm
- Forum: Naming
- Topic: Roman numeral [ENDORSED]
- Replies: 3
- Views: 844
Re: Roman numeral [ENDORSED]
The roman numeral usually goes after the metal at the end in parenthesis and it gives the metal's oxidation state, which is basically the charge of the metal. In order to figure this out, you have to look at the charge of what is given and determine what charge of the metal would add up to that char...
- Wed Nov 02, 2016 2:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Pyramidal
- Replies: 2
- Views: 1180
Re: Square Pyramidal
Well since there is a lone pair, it causes the bonds on the sides to push down making them less than 90 degrees.
- Wed Oct 26, 2016 7:31 pm
- Forum: Resonance Structures
- Topic: Resonance Course Reader Example
- Replies: 2
- Views: 725
Re: Resonance Course Reader Example
You would only draw all of the resonance structures if you are asked to. Otherwise, if you were asked just to draw one structure, it would be best to draw the most stable one, but as long as you show that you can draw the Lewis Structure, I think you should be fine, so don't worry, the question shou...
- Wed Oct 26, 2016 7:25 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Characters
- Replies: 5
- Views: 2535
Re: Ionic Characters
Also, you can determine the ionic character of a molecule by looking at the periodic table. The farther away the elements are, the greater the ionic character and vice versa for covalent character; the closer the elements, the greater the ionic character.
- Wed Oct 26, 2016 7:22 pm
- Forum: Lewis Structures
- Topic: Lewis Structure Octet Rule Exceptions
- Replies: 3
- Views: 1610
Re: Lewis Structure Octet Rule Exceptions
It a good "rule of thumb" to know that anything after Carbon needs an octet. P, S, Cl and beyond can have more than 8 electrons because of the d block in the 3rd period.
- Thu Oct 20, 2016 2:48 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Lewis structures
- Replies: 11
- Views: 2319
Re: Lewis structures
At one of the review sessions, the UA said that you're better off when the FC of the center atom is 0.
- Thu Oct 20, 2016 2:43 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: General Rules on Writing e- Configurations [ENDORSED]
- Replies: 2
- Views: 810
Re: General Rules on Writing e- Configurations [ENDORSED]
Well if you are looking for "general rules", it would be best to follow Hund's Rule and the Aufbau Principle because they tell you how you should be filling in the orbitals, which will make it easier for you to write the electron configuration.
- Wed Oct 12, 2016 9:13 pm
- Forum: Empirical & Molecular Formulas
- Topic: Quiz 1 Preperation Problem #2
- Replies: 2
- Views: 765
Re: Quiz 1 Preperation Problem #2
Hey Jazmin!
Yes, just add the percentages and subtract from 100% to get X%.
Yes, just add the percentages and subtract from 100% to get X%.
- Sat Oct 08, 2016 2:20 pm
- Forum: Photoelectric Effect
- Topic: The equation (pg. 13 of textbook) [ENDORSED]
- Replies: 1
- Views: 508
Re: The equation (pg. 13 of textbook) [ENDORSED]
Hey!
So the formula is basically saying
kinetic energy= energy of a photon - work function or threshold energy
In other words,
"1/2mv^2" is what is used to find the kinetic energy.
"hv" is the energy of the photon.
"Φ" is the work function.
Hope this helps!
So the formula is basically saying
kinetic energy= energy of a photon - work function or threshold energy
In other words,
"1/2mv^2" is what is used to find the kinetic energy.
"hv" is the energy of the photon.
"Φ" is the work function.
Hope this helps!
- Fri Oct 07, 2016 9:42 pm
- Forum: Significant Figures
- Topic: When to Apply Sig Figs [ENDORSED]
- Replies: 2
- Views: 881
Re: When to Apply Sig Figs [ENDORSED]
Also, to check if you have the right amount of sig figs, you can look at the number of sig figs that the problem started with.
- Thu Sep 29, 2016 8:38 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 440730
Re: Rusty on High School Chem [ENDORSED]
Yeah, its been a while since I took Chem and my teacher was not the best, so there are some fundamentals that I learned through Professor Lavelle's modules. (Thanks Professor!) I would recommend going to office hours whenever you feel like lost or super confused. You can go to the Professor's hours ...
- Sun Sep 25, 2016 4:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework Assignment?
- Replies: 7
- Views: 1262
Re: Homework Assignment?
If you look at your syllabus under "Review of Physical and Chemical Principles", there is a list of problems that we are supposed to do for homework. He's referring to M21 in that section.
- Sun Sep 25, 2016 4:36 pm
- Forum: Student Social/Study Group
- Topic: Rieber Hall 14A Study Group (Fall 2016)
- Replies: 49
- Views: 10149
Re: Rieber Hall 14A Study Group (Fall 2016)
I live in Rieber Hall and I am interested. :)