Search found 25 matches

by Navi Sidhu 1F
Thu Mar 16, 2017 2:06 pm
Forum: *Haloalkanes
Topic: Priority when Naming
Replies: 2
Views: 512

Re: Priority when Naming

First functional groups, then double/triple bonds and then substituents. So you're correct. Dr. Lavelle has stated he wouldn't give us 2 functional groups. See the forum below for verification. Check out this long thread for more info: https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=83&t=200...
by Navi Sidhu 1F
Thu Mar 16, 2017 1:54 pm
Forum: *Cyclopropanes and Cyclobutanes
Topic: Torisonal vs. Steric Strain
Replies: 2
Views: 613

Re: Torisonal vs. Steric Strain

Torsional Strain: When rotating a molecule around a bond, the torsional strain is the repulsion caused by the electrons in between different groups when they pass by each other. Torsional strain can be lessened by rotating a molecule around a bond. Steric Strain: Strain caused by the electrons in be...
by Navi Sidhu 1F
Sun Mar 12, 2017 6:33 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Torsional Strain
Replies: 1
Views: 239

Re: Torsional Strain

When a molecule is able to rotate around a sigma bond, there is bound to be different levels of torsional strain that vary with the placements of the substituents relative to each other. This leads to different conformations of molecules (such as staggered or eclipsed) with different energy levels, ...
by Navi Sidhu 1F
Sat Mar 04, 2017 8:52 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Activation energy [ENDORSED]
Replies: 1
Views: 433

Re: Activation energy [ENDORSED]

The minimum energy requirement that must be met for a chemical reaction to occur is called the activation energy, Ea. The activation energy (Ea), labeled ΔG‡ is the energy difference between the reactants and the activated complex, also known as transition state. In a chemical reaction, the transiti...
by Navi Sidhu 1F
Sun Feb 26, 2017 4:39 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Relationship between k, T, and Ea Graph
Replies: 1
Views: 224

Re: Relationship between k, T, and Ea Graph

The y-axis is the fraction of molecules, so if the peak of the high temperature curve is lower that means that there are less molecules at that certain level of kinetic energy. As the graph shows, the further right you go on the x-axis, the greater the kinetic energy. I assume that fraction of molec...
by Navi Sidhu 1F
Sat Feb 18, 2017 7:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams [ENDORSED]
Replies: 3
Views: 361

Re: Cell Diagrams [ENDORSED]

If you have non metal/ion pair undergoes redox, most of the time you need solid electrode to supply e-. These electrodes can be on either ends of the cell diagram.
by Navi Sidhu 1F
Sun Feb 12, 2017 8:37 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Comparing molar entropies of different molecules
Replies: 1
Views: 307

Re: Comparing molar entropies of different molecules

A question like this was asked in our last quiz. Basically what it comes down to is: Number of atoms/Number of unique positions of the atoms (degeneracy) Rigidity of bonds For example, which has larger molar entropy, CO or N 2 ? t=0K, and both molecules have the same geometry. Since the number of at...
by Navi Sidhu 1F
Sat Feb 04, 2017 1:03 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: H2O->H+ + OH-
Replies: 2
Views: 572

Re: H2O->H+ + OH-

This was a response by Chemmod a couple of years ago: This reaction is the opposite of Problem 13.11d so to make the comparison easier I will flip this reaction (this does not change the chemistry). In that problem you are given the cell diagram to help in the selection and you then solve for the f...
by Navi Sidhu 1F
Sat Jan 28, 2017 8:59 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 5
Views: 552

Re: Sig Figs

Prof Lavelle typically requires us to round at the end of a calculation.
by Navi Sidhu 1F
Sat Jan 28, 2017 8:54 pm
Forum: Van't Hoff Equation
Topic: Van't hoff equation
Replies: 1
Views: 410

Re: Van't hoff equation

The Van't Hoff Equation allows us to see how temperature changes can affect K. Here is a breakdown of the components of the equation: K 1 = initial equilibrium constant K 2 = final equilibrium constant \Delta H ^{_{\circ }} = standard formation of enthalpy R= Gas constant T 1 = initial temperature T...
by Navi Sidhu 1F
Sun Jan 22, 2017 10:36 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: open system
Replies: 2
Views: 301

Re: open system

I like to think of these problems like they have a moveable piston; one that moves up or down while responding to volume changes inside the beaker/cylinder in order to make the internal and external pressure equal, as it is in a open system. For example, Gas A (3 L) and Gas B (2 L) react to form 6 L...
by Navi Sidhu 1F
Sun Jan 22, 2017 10:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Exam Formula Sheet
Replies: 2
Views: 279

Re: Exam Formula Sheet

The equations on the back-side of the laminated periodic table you received with your course reader are all the possible equations and constants Prof Lavelle will supply us during an exam. In Chem14A, he picked the formulas that were relevant to us as the time and attached them to the test; I'm assu...
by Navi Sidhu 1F
Sun Jan 15, 2017 5:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Username
Replies: 2
Views: 435

Re: Username

1. Login 2. On the top right hand of your screen, click on your current username . (it has a upside-down triangle next to it; this will open three more options in a drop down box) 3. Click on User Control Panel 4. Under edit account settings , change your username 5. Enter your current password in t...
by Navi Sidhu 1F
Sun Jan 15, 2017 5:51 pm
Forum: Phase Changes & Related Calculations
Topic: CLOSED vs ISOLATED
Replies: 3
Views: 344

Re: CLOSED vs ISOLATED

In a open system, the system is not sealed and is not insulated . In a closed system, the system is sealed but is not insulated . In a isolated system, the system is sealed and insulated . When a system is sealed, matter cannot be exchanged with its surrounding; when it's not sealed it can. When a s...
by Navi Sidhu 1F
Wed Nov 30, 2016 5:07 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemical Equilibria
Replies: 1
Views: 321

Re: Chemical Equilibria

I'm assuming yes because in the course reader it is outlined how to convert between Partial Pressure (Kp) and Concentration (K). See page 133.
by Navi Sidhu 1F
Sun Nov 27, 2016 9:53 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1018404

Re: Post All Chemistry Jokes Here

An atom loses an electron.

It says, "Man, I really have to keep a better ion them!"
by Navi Sidhu 1F
Sun Nov 27, 2016 9:39 pm
Forum: Identifying Acidic & Basic Salts
Topic: Identifying a salt
Replies: 4
Views: 619

Re: Identifying a salt

Taken from http://study.com/academy/lesson/what-is-salt-in-chemistry-definition-formula.html because they have a clear, concise definition: In chemistry, a salt is an ionic compound which is made up of two groups of oppositely charged ions. The ion with a positive charge is called a cation, and the ...
by Navi Sidhu 1F
Sat Nov 12, 2016 1:42 pm
Forum: Naming
Topic: Oxidation Numbers
Replies: 1
Views: 214

Re: Oxidation Numbers

You determine the charges on all the ligands/atoms. If the molecule is neutral (which coordination compounds by their very definition are), then the charges must equal zero; therefore, the oxidization number of the central atom will equal whatever charge makes the molecule neutral. Here is a very si...
by Navi Sidhu 1F
Wed Nov 02, 2016 2:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Pyramidal
Replies: 2
Views: 391

Re: Square Pyramidal

These (credible) websites suggest that it's 90/120 degree angles. http://chem.libretexts.org/Core/Inorganic_Chemistry/Molecular_Geometry/Square_Pyramidal http://butane.chem.uiuc.edu/pshapley/GenChem2/A1/3.html http://homepage.smc.edu/scholefield_michelle/chem11/handouts/VSEPR%20Theory%20and%20the%20...
by Navi Sidhu 1F
Sun Oct 30, 2016 9:36 pm
Forum: Dipole Moments
Topic: Dipole Moments And Polarity
Replies: 1
Views: 546

Re: Dipole Moments And Polarity

Dipole moments can cancel if the molecule is symmetrical. Example: BeF 2 . The charges are vectors so if they go in opposite directions and have the same charge, (when you add them) they will cancel. You don't really need to have knowledge of vectors, just know if it's going in opposite directions a...
by Navi Sidhu 1F
Sun Oct 23, 2016 6:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma and Pi Bonds
Replies: 2
Views: 402

Re: Sigma and Pi Bonds

We will not be tested on Sigma and Pi bonds in quiz #2. Only material from chapter 2-3.
by Navi Sidhu 1F
Sun Oct 23, 2016 6:54 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1018404

Re: Post All Chemistry Jokes Here

Why did carbon marry hydrogen?
They bonded really well from the moment they met.
by Navi Sidhu 1F
Sun Oct 16, 2016 10:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1018404

Re: Post All Chemistry Jokes Here

Here's another one from chemistry cat:
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by Navi Sidhu 1F
Fri Oct 07, 2016 2:42 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Question [ENDORSED]
Replies: 3
Views: 459

Orbital Question [ENDORSED]

Is it still accurate/appropriate to write (for example, carbon) 1s2 2s2 2p2 instead of what we learned today: 1s2 2s2 2px1 2py1 ?

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