## Search found 28 matches

Thu Dec 07, 2017 5:54 pm
Forum: Conjugate Acids & Bases
Topic: 12.9 C
Replies: 1
Views: 167

### Re: 12.9 C

I think the proton transfer equation would be CH3COOH + NH3 -> CH3COO- + NH4+.
Thu Dec 07, 2017 5:37 pm
Forum: Lewis Acids & Bases
Topic: Lewis Structure in identifying Acid or Base
Replies: 2
Views: 198

### Re: Lewis Structure in identifying Acid or Base

Lewis bases will have lone pairs of electrons that can be used to bond to another atom, like in NH3 for example, where N has a lone pair. Lewis acids will be "electron deficient" species, species that could accept more electrons. Some examples are BF3 where B has an incomplete octet, Pt4+,...
Sun Dec 03, 2017 6:59 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH of neutral water and temperature
Replies: 2
Views: 168

### Re: pH of neutral water and temperature

Yea but can anyone explain why?
Sun Dec 03, 2017 6:56 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH of neutral water and temperature
Replies: 2
Views: 168

### pH of neutral water and temperature

What effect does temperature have on the pH of neutral water?
Sat Dec 02, 2017 3:10 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination number/polydentates [ENDORSED]
Replies: 1
Views: 134

### Re: coordination number/polydentates[ENDORSED]

The coordination number of a compound is equal to the number of points at which ligands are attached so for polydentate ligands you have to count all the binding sites. For example, the coordination number of [PtCl2(en)2]2+ is 6 because en is bidentate.
Sun Nov 26, 2017 1:41 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 11.43
Replies: 1
Views: 175

### Re: 11.43

Start by setting up your ICE table. The Initial partial pressures are 1.0 for NO, and 0 for O2 and N2. The Change is equal to +x for N2 and O2 and -2x for NO, since 2 mol of NO are required for each mol of O2 and N2 produced. Finally, your equilibrium pressures are (1.0 - 2x) for NO, and +x for N2 a...
Fri Nov 24, 2017 11:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.41
Replies: 1
Views: 290

### Re: Homework 11.41

The equilibrium constant is equal to Kc = [NH3]^2[CO2]. The concentration of ammonium carbamate doesn't go into the equation because it is in solid form. You can calculate the concentration of CO2 by first finding the number of mol of CO2 and dividing by the volume of the flask. As for NH3, the bala...
Sun Nov 19, 2017 4:49 pm
Forum: Naming
Topic: Hg(CH3)
Replies: 2
Views: 191

### Re: Hg(CH3)

In the textbook! Page 743 at the bottom.
Sun Nov 19, 2017 4:16 pm
Forum: Naming
Topic: Hg(CH3)
Replies: 2
Views: 191

### Hg(CH3)

What does the (0) in the name of this compound, dimethylmercury(0), refer to ? Isn’t the oxidation of Hg 2+?
Sun Nov 19, 2017 3:24 pm
Forum: Naming
Topic: Example 17.1
Replies: 2
Views: 181

### Example 17.1

In part b of this example, how do we know that the oxidation state of Pt is 4+?
Sun Nov 19, 2017 2:28 pm
Forum: Biological Examples
Topic: [Fe(NCS)(OH2)5]2+ name
Replies: 6
Views: 416

### Re: [Fe(NCS)(OH2)5]2+ name

Based on the rules in the toolbox shouldnt the name of this compound be pentaaquathiocyanato(kN or kS depending on the connectivity)iron(III) ion ?
Sun Nov 19, 2017 2:25 pm
Forum: Biological Examples
Topic: [Fe(NCS)(OH2)5]2+ name
Replies: 6
Views: 416

### [Fe(NCS)(OH2)5]2+ name

Can someone please explain why the name of this compound is thiocyanatopentaaqua(III) iron? Shouldn’t pentaaqua be first in the name since ligands are named in alphabetical order? And shouldn’t (III) be after iron, since it denotes its oxidation state?
Sun Nov 12, 2017 8:56 pm
Forum: Electronegativity
Topic: Determine Electron Affinity
Replies: 2
Views: 211

### Re: Determine Electron Affinity

I think Pd has a lower electron affinity than Ni because it has a complete 4d10 subshell. As for Cu and Ag, which have the same valence shell configuration, Ag might have a slightly higher electron affinity than Cu because it has more protons? The difference between their electron affinities is very...
Sun Nov 12, 2017 6:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: ICl3 shape
Replies: 1
Views: 352

### Re: ICl3 shape

Two regions! The two lone pairs repel each other very strongly and the most stable configuration is when they are as far apart as possible. This molecule has the same geometry as ClF3 — the two lone pairs are situated at equatorial positions 120 degrees apart.
Sat Nov 04, 2017 3:37 pm
Forum: Dipole Moments
Topic: Bond length [ENDORSED]
Replies: 4
Views: 308

### Re: Bond length[ENDORSED]

The length of the bond is the distance between the centers of the atoms. The dipole moment depends on the multiplicity of the bond, as the length of the bond decreases with multiplicity (i.e., a double bond between two elements is shorter than a single bond between them, a triple bond shorter than a...
Fri Nov 03, 2017 6:23 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge of Carbon in CH3
Replies: 2
Views: 3469

### Re: Formal Charge of Carbon in CH3

C has two lone electrons, so FC = V - (L + S/2) = 4 - (2 +6/2) = -1
Fri Nov 03, 2017 6:14 pm
Forum: Bond Lengths & Energies
Topic: Bond Strength
Replies: 5
Views: 452

### Re: Bond Strength

Can you give an example of a molecule you are referring to? Your question might be easier to answer when looking at a specific molecule.
Sat Oct 28, 2017 2:35 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration for Fe^2+ [ENDORSED]
Replies: 2
Views: 223

### Re: Electron configuration for Fe^2+[ENDORSED]

It's because the 4s electrons are higher in energy and so they can be removed more easily than electrons from the 3d shell.
Tue Oct 24, 2017 6:14 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Possible Quantum numbers given n=6
Replies: 3
Views: 247

### Re: Possible Quantum numbers given n=6

All values of l up to l=5 are possible and I think should be listed. Although there are no known elements that have their 6f, 6g or 6h orbitals occupied when they are in their ground state, these orbitals could be occupied if the electrons are given enough energy -- the atom would then be in an exci...
Tue Oct 24, 2017 2:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Weekly online discussion points
Replies: 3
Views: 284

### Weekly online discussion points

I just checked my grades for Chem 14A on my.ucla and although hw and test 1 have been uploaded, Weekly Online Discussion says N/A although I have been posting regularly. Does it look like this for everyone else too? Does anyone know if they are all uploaded at the end of the quarter?
Thanks!
Fri Oct 20, 2017 4:37 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Effective Nuclear Charge
Replies: 1
Views: 156

### Re: Effective Nuclear Charge

The electron in one electron atoms experiences the electrostatic attraction of the full charge of the nucleus. The situation is different in multi electron atoms however. The electrons in the outer shells are not only attracted by the positive nucleus, but also repelled by the other electrons and th...
Thu Oct 19, 2017 6:43 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Homework 2.29
Replies: 2
Views: 214

### Re: Homework 2.29

Each electron is described by four quantum numbers n, l, ml, ms. When n = 2, l takes values l = 0, 1 (corresponding to s and p orbitals like you said). For l=0, ml =0, and for l = 1, ml = -1,0,1. For each n,l,ml combination we can have ms = 1/2 or ms = -1/2. Here are the quantum numbers of the elect...
Sun Oct 15, 2017 10:48 am
Forum: DeBroglie Equation
Topic: Units for Mass [ENDORSED]
Replies: 3
Views: 223

### Re: Units for Mass[ENDORSED]

You have to convert to kg because the Planck constant is in units of J s and 1 J = kg m^2/ s^2.
Thu Oct 12, 2017 8:06 pm
Forum: *Shrodinger Equation
Topic: Help on Self-Test 1.8A
Replies: 4
Views: 318

### Re: Help on Self-Test 1.8A

For c, me and h the same as the example above. L^2 comes out to 10^-20 m^2. Is that what you have for L^2?
Thu Oct 12, 2017 8:00 pm
Forum: Properties of Light
Topic: 1.27
Replies: 3
Views: 214

### Re: 1.27

1 mol of photons is 6.022 x 10^23 photons. The definition of the mole is that it contains as many objects(not necessarily atoms) as there are atoms in 12g of carbon-12.
Thu Oct 12, 2017 7:38 pm
Forum: *Shrodinger Equation
Topic: Help on Self-Test 1.8A
Replies: 4
Views: 318

### Re: Help on Self-Test 1.8A

I just did it and got the right answer. What I did was solve for the wavelength first and plug in the numbers at the end, just like they do in the example. I found that in problems like this you can end up with the wrong final answer if you plug in numbers earlier to calculate energy, frequency etc....
Thu Oct 05, 2017 11:23 pm
Forum: Limiting Reactant Calculations
Topic: M9
Replies: 4
Views: 403

### Re: M9

I was wondering the same thing! This question was asked earlier and someone replied that we don’t need to know how to write ionic equations. It wasn’t covered in lecture or the readings so I don’t think it would be something we would be tested on!
Thu Oct 05, 2017 7:57 pm
Forum: Limiting Reactant Calculations
Topic: M6
Replies: 1
Views: 210

### Re: M6

Since 3 mol of N2H4 react with 4 mol of ClF3 , if we have 12 mol of ClF3 only 9 mol of N2H4 are necessary, so 3 mol of N2H4 will be in excess. As for the products, if 4 mol of ClF3 give 12 mol of HF, how many mol of HF would you get for 12 mol of ClF3? Does this make sense?