Search found 16 matches

by Nima Ghorashi 3A
Wed Dec 03, 2014 11:45 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quiz 3 Prep #8
Replies: 1
Views: 1365

Re: Quiz 3 Prep #8

Hi Vivien,

I have attached a picture of the solution of how I solved the problem.
So you can ignore the solid in the equation and focus on the gases. This will give you the ice table in the picture and then you set the equation up to the constant given and you get the value of x which is the answer.
by Nima Ghorashi 3A
Wed Dec 03, 2014 1:39 am
Forum: Naming
Topic: How do you determine the oxidation number of anions?
Replies: 3
Views: 959

Re: How do you determine the oxidation number of anions?

Alright so for C we do not know the charge of the cation. In order to find the charge of Co we must first find the total charge of the anions and give the cation the positive charge of that in order to give the complex a negative charge of 2-. Since we know that CN has a charge of -1 and there are 5...
by Nima Ghorashi 3A
Wed Dec 03, 2014 12:58 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quiz 3 Question
Replies: 1
Views: 403

Re: Quiz 3 Question

Hi Polly, So Im not sure where you see this on quiz three in the workbook, but ill try to help anyway. So first you need to find the partial pressure of nh3 is, which can be done by (.36)(200)=72atm Now we are left with 128 atm for the reactants. In order to find the values of the reactants, we must...
by Nima Ghorashi 3A
Tue Dec 02, 2014 11:29 pm
Forum: Naming
Topic: How do you determine the oxidation number of anions?
Replies: 3
Views: 959

Re: How do you determine the oxidation number of anions?

Hi Reeva, So first off, in a coordination compound the ligands are directly attached to the central ion, which is a central metal cation atom where transition metals form complexes, that make up the coordination sphere. Finding the anion charge goes hand in hand with equaling out the positive charge...
by Nima Ghorashi 3A
Tue Dec 02, 2014 10:16 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: When to use Partial Pressure notation
Replies: 1
Views: 486

Re: When to use Partial Pressure notation

Hey Nicole, So first off, your assumption is correct about kp for gases and kc for concentrations of aqueous solutions. For 10.7 all three of the parts have homogenous equations, which are all gases. The problem is allowed to ask for kc because if you recall, you can switch from pressure to concentr...
by Nima Ghorashi 3A
Tue Nov 25, 2014 7:51 pm
Forum: Naming
Topic: writing a formula given the naming of a compound
Replies: 1
Views: 435

Re: writing a formula given the naming of a compound

Hello Grecia, If you get a chance, the Toolbox 16.1 in the textbook is very helpful and outlines the rules for both naming and writing formulas. Anyways, it says that you usually write the chemical symbol of the metal, followed by the symbols for the ligands. The chemical symbols of the ligands are ...
by Nima Ghorashi 3A
Tue Nov 25, 2014 6:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Periodic Table Song
Replies: 5
Views: 854

Re: Periodic Table Song

I have attached the video of the student singing the periodic table song. This is also on YouTube.

The Periodic Table of Elements Song in Chem 14A.3gp [ 4.15 MiB | Viewed 818 times ]



Source: https://www.youtube.com/watch?v=3zxDakL ... e=youtu.be
by Nima Ghorashi 3A
Tue Nov 25, 2014 5:32 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8238
Views: 1437021

Re: Chemistry Jokes

Friend: "Johnny, why have you been so upset and frustrated lately?"

Johnny: "Well, I have taken two years and a quarter of chemistry, and I have yet to get this girl's significant digits."
by Nima Ghorashi 3A
Tue Nov 25, 2014 5:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 10.53
Replies: 2
Views: 1123

Re: Homework 10.53

Hi Erica, So for the percentage it says that 60% of the hydrogen has reacted, which means 40% remains. You can then use the 40% to find the change in concentration of of H2 at equilibrium by (.400)(0.133mol/L-x). So if you subtract the original concentration value by 40%, you will end up with the 60...
by Nima Ghorashi 3A
Mon Nov 03, 2014 10:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Hybridization and bond types
Replies: 2
Views: 553

Re: Hybridization and bond types

Hello Jason, So recalling the notes from lecture, the number of orbitals is conserved and you can say that for 4 atomic orbitals there are 4 hybrid orbitals. Furthermore, the regions of electron density is equal to the number of hybrid orbitals. This shows shows that, no matter a sigma or pi bond, a...
by Nima Ghorashi 3A
Thu Oct 09, 2014 9:04 pm
Forum: Photoelectric Effect
Topic: Wavelength
Replies: 3
Views: 693

Re: Wavelength

Hi Mohak,

Did your answer by any chance have the decimal after the first number? For example, if you got 5.54e-7, its the same as 554e-9. I remember a few of the problems being like this.
by Nima Ghorashi 3A
Thu Oct 09, 2014 8:57 pm
Forum: Significant Figures
Topic: Scientific Notation vs Decimal
Replies: 2
Views: 615

Re: Scientific Notation vs Decimal

Hi Nikolina, Dr. Lavelle posted a very helpful document named "Everything you want to know about Sig Figs" under course materials on his webpage. https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/EVERYTHING_YOU_WANTED_TO_KNOW_ABOUT_SF.pdf"onclick="window.open(this.href);ret...
by Nima Ghorashi 3A
Wed Oct 08, 2014 12:50 am
Forum: Limiting Reactant Calculations
Topic: Quiz 1 Prep Fall 2012 Q3
Replies: 3
Views: 7534

Re: Quiz 1 Prep Fall 2012 Q3

Hi Loo, I do understand the confusion because there is excess and the reaction will not be able to react all of the O2 due to this excess, you are right. So what I'm thinking is that Dr.Lavelle might have asked to show that NO is the limiting reactant both through the moles of NO vs O2, but also the...
by Nima Ghorashi 3A
Wed Oct 08, 2014 12:23 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Atoms versus Molecules
Replies: 1
Views: 596

Re: Atoms versus Molecules

Hi Victoria, So if we derive Avogadro's constant it might help explain why. Number of carbons atoms= (12g of mass sample of Carbon)/(1.99265e-23 mass of one Carbon atom)=6.0221e23 This is a quote from the textbook: "1 mole of atoms of any element, 1 mol of ions, and 1 mol of molecules each cont...
by Nima Ghorashi 3A
Tue Oct 07, 2014 9:23 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.5
Replies: 2
Views: 664

Re: G.5

Hi Jennifer, So in this particular aqueous solution there are two components: K2NO3 and water. The entire mass of the aqueous solution is given, which is 510.g of total solution. Of that 510.gram solution, 5.45% is that of K2NO3. (Total mass) x (mass percent of part)=mass of part. Then, the remainin...

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