Search found 31 matches
- Sun Jun 03, 2018 11:25 pm
- Forum: Bond Lengths & Energies
- Topic: Test 3 Q 8 [ENDORSED]
- Replies: 9
- Views: 1302
Re: Test 3 Q 8 [ENDORSED]
So a localized double bond is essentially stronger then a delocalized bond?
- Sun Jun 03, 2018 11:22 pm
- Forum: Dipole Moments
- Topic: dipole moments
- Replies: 9
- Views: 1667
Re: dipole moments
Because of the higher strength of electronegativity - would the C-Cl bond be considered more polar?
- Sun Jun 03, 2018 11:09 pm
- Forum: Hybridization
- Topic: Atomic orbitals vs hybrid orbitals
- Replies: 2
- Views: 400
Re: Atomic orbitals vs hybrid orbitals
I found these notes from another UCLA chemistry professor and they seem to break everything down step by step. The diagrams have helped me visualize what is actually going on. If you are a visual learner this may help you remember the process better. Hope it helps! http://www.chem.ucla.edu/~harding/...
- Sun Jun 03, 2018 11:02 pm
- Forum: Hybridization
- Topic: Hybrid orbitals
- Replies: 6
- Views: 745
Re: Hybrid orbitals
# of regions of electron density = # bonds and lone pairs around an atom
- a double bond, triple bond, or a lone pair counts as only one region of electron density
- a double bond, triple bond, or a lone pair counts as only one region of electron density
- Sun Jun 03, 2018 10:53 pm
- Forum: Sigma & Pi Bonds
- Topic: delocalized and localized pi bond
- Replies: 3
- Views: 11448
Re: delocalized and localized pi bond
These two examples may help you visualize -
Delocalized:
Localized:
Delocalized:
Localized:
- Sun May 27, 2018 11:49 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Water effect 11.115
- Replies: 2
- Views: 590
Re: Water effect 11.115
Cant water also be a gas? Water vapor?
- Sun May 27, 2018 11:48 pm
- Forum: Ideal Gases
- Topic: PV=nRT
- Replies: 3
- Views: 646
Re: PV=nRT
If you were trying to find the volume you would simply multiply P to both sides and end up with Charles's law (aka law of volumes).
- Sun May 27, 2018 11:32 pm
- Forum: Sigma & Pi Bonds
- Topic: Bond Strength/Bond Type
- Replies: 3
- Views: 771
Bond Strength/Bond Type
I understand the difference between sigma and pi bonds, however in terms of bond strength I get confused. Sigma bonds are in general more difficult to break because the nuclei have a strong hold on the e - ... Yet we are taught single bonds are weaker than double bonds? Is that just because a single...
- Mon May 21, 2018 12:20 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Dipole moments
- Replies: 3
- Views: 693
Re: Dipole moments
The unequal sharing of electrons within a bond leads to the formation of an electric dipole (a separation of positive and negative electric charges). Bonds can fall between one of two extremes, from completely nonpolar to completely polar . see: https://courses.lumenlearning.com/boundless-chemistry...
- Mon May 21, 2018 12:06 am
- Forum: Lewis Structures
- Topic: How do I start a Lewis structure?
- Replies: 3
- Views: 619
Re: How do I start a Lewis structure?
I would watch this Khan video, it goes through the steps for beginning the Lewis Structure! https://www.khanacademy.org/science/chemistry/chemical-bonds/copy-of-dot-structures/v/drawing-dot-structures --> In general the least electronegative element goes in the middle! --> Cyclic compounds = ring co...
- Mon May 21, 2018 12:01 am
- Forum: Octet Exceptions
- Topic: Octet Exception
- Replies: 7
- Views: 1084
Re: Octet Exception
odd-electron molecules molecules with an odd number of electrons (e.g., NO). Electron-deficient molecules molecules in which atoms have fewer than 8 electrons (e.g., boron chloride and lighter s- and p- block elements ) ie. Hydrogen, Beryllium, and Boron = too few electrons to form octet ----> Hydr...
- Sun May 20, 2018 11:43 pm
- Forum: Lewis Structures
- Topic: Lewis Dot vs Lewis Structure
- Replies: 3
- Views: 640
Re: Lewis Dot vs Lewis Structure
Lewis symbol: Formalism in which the valence electrons of an atom are represented as dots. Lewis structure: Formalism used to show the structure of a molecule or compound, in which shared electrons pairs between atoms are indicated by dashes. Non-bonding, lone pairs of electrons must also be shown....
- Sun May 13, 2018 7:06 pm
- Forum: Octet Exceptions
- Topic: Concept of Exceptions
- Replies: 4
- Views: 672
Re: Concept of Exceptions
Third period elements occasionally exceed the octet rule by using their empty d orbitals to accommodate additional electrons Size is also an important consideration: The larger the central atom, the larger the number of electrons which can surround it Expanded valence shells occur most often when t...
- Sun May 13, 2018 7:01 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent vs Metallic Bonds
- Replies: 6
- Views: 1309
Re: Ionic vs Covalent vs Metallic Bonds
"Ionic bonds form due to the transfer of an electron from one atom to another. Covalent bonds involve the sharing of electrons between two atoms. Metallic bonds are formed by the attraction between metal ions and delocalized, or "free" electrons." See: https://www.khanacademy.org...
- Sun May 13, 2018 6:54 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions to Ionization Energy Trend
- Replies: 2
- Views: 995
Re: Exceptions to Ionization Energy Trend
Electron configurations seem to create these exceptions.. For the N and O on the second row of the periodic table: "The electron configuration of nitrogen is 1s22s22p3, a stable, half-filled structure. Oxygen has an electron configuration of 1s22s22p4 --one electron beyond stable. So, taking an...
- Sun May 06, 2018 11:56 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: "ms" Quantum Number [ENDORSED]
- Replies: 2
- Views: 631
Re: "ms" Quantum Number [ENDORSED]
I believe if the question gives you all quantum four numbers (the Principal Quantum Number "n", Orbital Angular Momentum Quantum Number "l", Magnetic Quantum Number "m l " and Electron Spin Quantum Number "m s ") then only 1 electron can be in that exact state...
- Sun May 06, 2018 11:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: Midterm Topics [ENDORSED]
- Replies: 33
- Views: 4705
Re: Midterm Topics [ENDORSED]
Phil Timoteo wrote:I believe the midterm will cover material from chapter 1&2
I also believe the fundamentals section, that was covered on the first test, will also be on the midterm exam!
- Wed May 02, 2018 1:34 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Example 1.7
- Replies: 2
- Views: 500
Example 1.7
Hello! In text example 1.7 (p. 18) - Estimate the minimum uncertainty in: (a) the position of an object as heavy as a marble of mass 1.0 g given that its speed is known within + 1.0mm/s and (b) the speed of an electron confined to within the diameter of a typical atom (200. pm). Why is \Delta v = 2 ...
- Tue May 01, 2018 9:00 pm
- Forum: Properties of Light
- Topic: Test #2: Q6 [ENDORSED]
- Replies: 10
- Views: 1259
Re: Test #2: Q6 [ENDORSED]
I also used wavelength=hc/E, but the way you do it works too. With rounding the answer is 10 x 10^7 (positive exponent of 7, not negative, because there's 10^9 nanometers in one meter) If you don't mind explaining more, just so I can possibly understand, why would 10^9 nanometers in one meter make ...
- Tue May 01, 2018 8:56 pm
- Forum: DeBroglie Equation
- Topic: Test #2: Q5 [ENDORSED]
- Replies: 9
- Views: 1266
Re: Test #2: Q5 [ENDORSED]
yazminedesan1F wrote:How were you able to see the quiz earlier than discussion?
My TA passed our quizzes out after class on Friday!
- Sun Apr 29, 2018 11:48 am
- Forum: Properties of Light
- Topic: Test #2: Q6 [ENDORSED]
- Replies: 10
- Views: 1259
Test #2: Q6 [ENDORSED]
I got the second part of this question incorrect, I am assuming because of an accident when inputting the numbers into my calculator. I have re-done the problem below and just want to make sure I am on the right track. Q6. Microwave ovens use microwave electromagnetic radiation to cause vibrations w...
- Sun Apr 29, 2018 11:23 am
- Forum: DeBroglie Equation
- Topic: Test #2: Q5 [ENDORSED]
- Replies: 9
- Views: 1266
Test #2: Q5 [ENDORSED]
I got this question wrong on the test -- I just want to make sure I am on the right track now. Thanks! Q5. Electrical signals within the body are transmitted by the movement of sodium ions in and out of neurons. When pain signals are sent, the local velocity of a sodium ion is assumed to be 1.34 m/s...
- Sun Apr 29, 2018 10:41 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Test 2 Q4 help [ENDORSED]
- Replies: 3
- Views: 557
Re: Test 2 Q4 help [ENDORSED]
The way this question was written really through me for a loop. I definitely was looking for a reason to use the Rydberg equation, however the given wavelength was my biggest indication that this was a c=lamda*v & E=hv problem. Using the word "difference" in the question made me think ...
- Sun Apr 22, 2018 4:43 pm
- Forum: *Black Body Radiation
- Topic: Black Body? [ENDORSED]
- Replies: 13
- Views: 2099
Re: Black Body? [ENDORSED]
Liliana Rosales 1E wrote:I believe black bodies absorb the entire electromagnetic spectrum not just the visible spectrum.
They do! A black body is an object that absorbs all radiation falling on it, at all wavelengths.
- Sun Apr 22, 2018 4:39 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Frequency if energy goes from n=2 to n=4
- Replies: 6
- Views: 560
Re: Frequency if energy goes from n=2 to n=4
When moving up energy levels light is absorbed & not emitted -- however ^^^ they are right, it cannot be negative!
- Sun Apr 22, 2018 4:34 pm
- Forum: Einstein Equation
- Topic: General Question about Joules [ENDORSED]
- Replies: 7
- Views: 1608
Re: General Question about Joules [ENDORSED]
Why do we often use "joule seconds"? In stead of J.s^-1?
- Fri Apr 20, 2018 1:47 am
- Forum: Properties of Light
- Topic: Memorizing Wavelengths [ENDORSED]
- Replies: 4
- Views: 498
Memorizing Wavelengths [ENDORSED]
Would it be optimal to memorize the wavelength regions radio--->gamma? Or would that be a waste of time?
- Fri Apr 20, 2018 1:34 am
- Forum: Ideal Gases
- Topic: Reading the textbook
- Replies: 262
- Views: 146707
Re: Reading the textbook
Personally I would only work out the pre & post module questions along with the assigned homework problems. Dr. Lavelle seems to do a good job of making what he wants you to know clear. If you try to do all the problems in the chapter you'll probably get overwhelmed. is it helpful to work out th...
- Fri Apr 20, 2018 1:22 am
- Forum: Naming
- Topic: Naming and Polyatomic Ions
- Replies: 6
- Views: 987
Re: Naming and Polyatomic Ions
Is it expected of us to memorize the polyatomic ions?
- Fri Apr 20, 2018 1:14 am
- Forum: Significant Figures
- Topic: Basic Sig Figs
- Replies: 13
- Views: 1929
Re: Basic Sig Figs
When you get the final answer for a problem, for example,
#2. CHEM, an FM radio station, broadcasts at 99.5 MHz. What is the wavelength of the corresponding radio waves?" (from TA worksheet 2)
would the resulting answer have be rounded to 3 sig figs because of the "99.5 MHz"?
#2. CHEM, an FM radio station, broadcasts at 99.5 MHz. What is the wavelength of the corresponding radio waves?" (from TA worksheet 2)
would the resulting answer have be rounded to 3 sig figs because of the "99.5 MHz"?
- Fri Apr 20, 2018 1:08 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Equation & Test 2
- Replies: 4
- Views: 474
Heisenberg Equation & Test 2
Will the application of the Heisenberg Equation be tested on next weeks test (test two)?