Search found 43 matches
- Tue Jun 12, 2018 9:16 pm
- Forum: Hybridization
- Topic: S-Character and Bond Angle Relationship
- Replies: 3
- Views: 2493
Re: S-Character and Bond Angle Relationship
S-character is the contribution of the sigma (single) bond in hybridization. In sp^3, there is 25% s-character and 75% p-character, whereas, in sp, there is 50% s-character and 50% p-character. Therefore, the more s-character a bond has, the stronger as well as the shorter bond becomes. S-character ...
- Tue Jun 12, 2018 9:07 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dipole Moments
- Replies: 1
- Views: 327
Re: Dipole Moments
I wouldn’t expect that on the final, but polar vs. nonpolar will for sure show up.
- Tue Jun 12, 2018 9:06 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: series
- Replies: 1
- Views: 308
Re: series
I would know it just in case. Lyman is n=1, Balmer is n=2, and Paschen n=3. The other two we haven’t really discussed, so I wouldn’t worry.
- Tue Jun 12, 2018 9:03 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: French Toast Number 27 Part B
- Replies: 4
- Views: 588
French Toast Number 27 Part B
Part a has us solve for the volume, which I got correctly, but I keep getting the wrong pH value for part b. Can someone explain step by step how to do this? I did moles/volume the -log that value.
- Sat Jun 09, 2018 10:35 pm
- Forum: Hybridization
- Topic: Hibridization
- Replies: 3
- Views: 610
Re: Hibridization
Hybridization is the mixing of orbitals into new orbitals to accommodate electrons to form new chemical bonds of the valence-bond theory. To solve for hybridization, look at the amount of electrons/atoms bonded to the central atom. For linear, there is 2 atomic orbitals as well as two hybrid orbital...
- Sat Jun 09, 2018 10:25 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis vs Bronsted
- Replies: 4
- Views: 576
Re: Lewis vs Bronsted
Lewis Acid: A molecule that accepts an electron Lewis Base: A molecule that donates an electron Brønsted Acid: A molecule that donates a H+ Brønsted Base: A molecule that accepts a H+ These are the main concepts to remember for the final exam as well as being able to tell apart which molecule is an ...
- Sat Jun 09, 2018 10:16 pm
- Forum: Ionic & Covalent Bonds
- Topic: Finding Bond order
- Replies: 2
- Views: 441
Re: Finding Bond order
To find the bond order, you create the Lewis structure first to see the amount of bonds in the molecule. For example, NH3, nitrogen has a bond order of 3 while hydrogen has a bond order of 1. It is just the amount of bonds created...including double and triple bonds.
- Sat Jun 09, 2018 10:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing Tetrahedral Structures
- Replies: 4
- Views: 702
Re: Drawing Tetrahedral Structures
We won’t be asked to draw the VSEPR models, but to know their names and bond angles. In all of our homework, we weren’t asked to draw VSEPR models, but instead, a Lewis structure.
- Sun Jun 03, 2018 9:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Benzene structure
- Replies: 2
- Views: 353
Re: Benzene structure
I would assume so because it is a common molecule we have gone over. Lavelle has mentioned C6H6 many times and even in homework we have figured out all of its resonance structures.
- Sun Jun 03, 2018 9:36 pm
- Forum: Hybridization
- Topic: Lone Pairs
- Replies: 5
- Views: 583
Re: Lone Pairs
I believe hybridization takes into account the lone pairs of a molecule. It is further explained on this document; http://www.chem.ucla.edu/~harding/notes ... als_01.pdf
- Sun Jun 03, 2018 9:31 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating Ligands
- Replies: 2
- Views: 536
Re: Chelating Ligands
A chelating ligands are ligands with two or more points of attachments to metal atoms. Some examples are ethylenediamine and acetylacetone. For more examples, this website has more descriptions and videos on chelating ligands. https://study.com/academy/lesson/chelating-ligands-definition-models-exam...
- Sun Jun 03, 2018 9:26 pm
- Forum: Biological Examples
- Topic: Biological Function on Final?
- Replies: 3
- Views: 516
Re: Biological Function on Final?
It may show up as multiple choice for the final so I would study it just in case.
- Sun May 27, 2018 1:14 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Remembering Bond Angles
- Replies: 4
- Views: 605
Re: Remembering Bond Angles
I'm assuming we need to know both the bond names and the shape they make as well especially since past tests that I've looked at asked for small details like that.
- Thu May 24, 2018 12:58 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge W/ Radicals
- Replies: 2
- Views: 1967
Re: Formal Charge W/ Radicals
It would still be the same formula to solve for formal charge, but you can tell the atom is radical if it has an unpaired electron or odd number of electrons. For example, CH3 would be a radical since it is 4+3= 7 electrons and when you make the Lewis structure it shows a lone electron.
- Thu May 24, 2018 12:54 pm
- Forum: Lewis Structures
- Topic: 3.45
- Replies: 2
- Views: 466
Re: 3.45
It asked specifically for a resonance structure, so I think you have to show what the structure looks like with a charge on certain atoms. The delocalized electrons have to be show in two different Lewis structures. I'm not fully sure, but I hoped that helped.
- Thu May 24, 2018 12:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Regions of electron density
- Replies: 7
- Views: 708
Re: Regions of electron density
I believe the lone pairs of electrons only count when they are around the central atom. I think the lone pairs around a non central atom would form a molecular structure called a bent or a gray circle representing the lone pair.
- Thu May 17, 2018 10:36 pm
- Forum: Lewis Structures
- Topic: Question 3.25
- Replies: 2
- Views: 792
Question 3.25
For question 3.25, "On the basis of the expected charges of the monatomic ions, give the chemical formula of each of the following compounds: (a) magnesium aresenide (b)barium arsenide...," does anyone have tips to solve for these quicker?
- Thu May 17, 2018 9:49 pm
- Forum: Ionic & Covalent Bonds
- Topic: Configurations
- Replies: 4
- Views: 538
Re: Configurations
Electrons are removed from the highest energy level because they are the furthest from the nucleus.
- Thu May 17, 2018 9:48 pm
- Forum: Lewis Structures
- Topic: Test #3
- Replies: 11
- Views: 1318
Test #3
Does anyone know how the test covers in terms of homework? Is it all of Chapter 3 or is it up to a certain problem?
- Thu May 17, 2018 2:23 pm
- Forum: Electronegativity
- Topic: Relationship between Electronegativity and Ionization Energy
- Replies: 4
- Views: 3126
Re: Relationship between Electronegativity and Ionization Energy
I believe the element in the middle (with the lowest ionization energy) would have the highest electronegativity since it has the strongest ability to attract other atoms towards it.
- Sun May 13, 2018 6:59 pm
- Forum: Trends in The Periodic Table
- Topic: Q 2.67
- Replies: 2
- Views: 366
Re: Q 2.67
Electron affinity increases going across (left to right) the rows and decreases go down columns. Carbon has a higher electron affinity than nitrogen due to its electron configuration. Carbon's electron configuration is 1s^2 2s^2 2p^2 and nitrogen's electron configuration is 12^2 2s^ 2p^3. Having two...
- Sun May 13, 2018 6:50 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions to Ionization Energy Trend
- Replies: 2
- Views: 996
Re: Exceptions to Ionization Energy Trend
Exceptions in ionization energy occurs because of the electron configuration. Taking away or adding electrons to certain atoms produces a more stable atom and creates a different ionization energy than what is expected. For example, Nitrogen's electron configuration is 1s^2 2s^2 2p^3, which is stabl...
- Sun May 13, 2018 6:44 pm
- Forum: Octet Exceptions
- Topic: Concept of Exceptions
- Replies: 4
- Views: 677
Re: Concept of Exceptions
I believe it would be due to the larger radii in the first two rows as the electrons cannot interact with the nucleus. Exceptions usually occur when molecules have an odd number of electrons, molecules that contain atoms that have less than an octet, and molecules that contain atoms with more than a...
- Tue May 08, 2018 2:06 pm
- Forum: Lewis Structures
- Topic: Electron Configuration
- Replies: 6
- Views: 753
Re: Electron Configuration
There isn't a formula to find l number; it is just standard numbers we need to know. s=0, p=1, d=2, f=3. The only other way to solve for it is through n-1= l max.
- Mon May 07, 2018 8:37 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Midterm Question
- Replies: 2
- Views: 369
Midterm Question
My TA told me that we have to have correct sig figs for the midterm. Is that still true?
- Sun May 06, 2018 8:26 pm
- Forum: Lewis Structures
- Topic: Electron Configuration
- Replies: 6
- Views: 753
Re: Electron Configuration
These numbers are determined by the l quantum number. The l number is the amount of orbitals an element can carry.
- Sun May 06, 2018 8:21 pm
- Forum: Trends in The Periodic Table
- Topic: 2.71
- Replies: 1
- Views: 214
Re: 2.71
What is a diagonal relationship? I looked it up and it said similarity in chemical properties between an element in the periodic table ande one group lying one period lower and one group to the right. I don’t remember him talking about this in class... do we need to know it for the midterm? They ex...
- Sun May 06, 2018 7:56 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Concept
- Replies: 2
- Views: 416
Re: Concept
Why is it that we can't know both position and momentum? According to the Uncertainith Principle, every particle has a wave associated with it, so it exhibits a wavelike behavior. A particle wave having a well-defined wavelength will be spread out, so the velocity will be precise but not the positi...
- Sun Apr 29, 2018 7:20 pm
- Forum: Photoelectric Effect
- Topic: Incident Light
- Replies: 3
- Views: 573
Re: Incident Light
QuincyH1G wrote:Threshold energy varies per metal correct?
Threshold does vary among different metals because the work function energy varies. The work function varies due to the position of the electrons in that metal. The shape of the metal determines where and how the electrons move off the metal.
- Sun Apr 29, 2018 7:11 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: hw 2.13 [ENDORSED]
- Replies: 2
- Views: 378
Re: hw 2.13 [ENDORSED]
They describe the locations of electrons in a P-orbital. So instead of saying "these electron are in the front and back," we can say "their positions are on the x-axis" since they are in P-orbital, we state their location as "Px" same idea for Py and Pz The lobes are i...
- Sun Apr 29, 2018 7:04 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Why does 4s fill up before 3d?
- Replies: 4
- Views: 471
Re: Why does 4s fill up before 3d?
The only reason I can think of is since the 3d state is higher in energy than the 4s state, the 4s state would fill up faster because it would take less energy. I would have to agree with Vivian as the 4s electrons are lost first during ionization. The electrons lost first, have the highest energy ...
- Sat Apr 21, 2018 7:32 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Uncertainty Question [ENDORSED]
- Replies: 2
- Views: 227
Re: Heisenberg Uncertainty Question [ENDORSED]
The numerical cutoff for delta p is h/4pi.delta x. The numerical cutoff for delta v is delta p/mass.
- Sat Apr 21, 2018 7:28 pm
- Forum: DeBroglie Equation
- Topic: Post-Assessment #34 [ENDORSED]
- Replies: 5
- Views: 506
Re: Post-Assessment #34 [ENDORSED]
I believe a speed is reasonable if it is less than the speed of light (3.00x10^8 m.s^-1). Your answer seems to be correct then because it is much smaller than the speed of light.
- Sat Apr 21, 2018 7:26 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: 1J=1kg.m^2.s^-2
- Replies: 3
- Views: 230
Re: 1J=1kg.m^2.s^-2
I'm not sure if I'm fully correct, but a Joule derives from a Newton (kg.m/s^2). Joules measures amount of work done on an object (mass) going through a distance of one meter. Which is why a Joule is a Newton times mass, so kg.m^2.s^-2.
- Sat Apr 21, 2018 7:14 pm
- Forum: Photoelectric Effect
- Topic: 1.21 [ENDORSED]
- Replies: 2
- Views: 581
1.21 [ENDORSED]
"From the following list of observations, select the one that best supports the idea that electromagnetic radiation has the properties of particles. Explain your reason." Can someone further explain the reasoning behind Einstein's theory of the photoelectric effect? Is he insisting that ph...
- Sat Apr 14, 2018 6:51 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Uncertainty Concept Question [ENDORSED]
- Replies: 1
- Views: 345
Re: Heisenberg Uncertainty Concept Question [ENDORSED]
The correct answer would be C. because according to the uncertainty principle, we cannot know both the velocity and position of an electron at the same moment. If we have definite value for the velocity of the electron, we cannot have certain answer for the position and placement of that electron. T...
- Sat Apr 14, 2018 6:29 pm
- Forum: Photoelectric Effect
- Topic: Released electrons [ENDORSED]
- Replies: 1
- Views: 176
Re: Released electrons [ENDORSED]
In the experiment, there is two plates of metal connected by wiring to create a circuit. Since the electrons are knocked off of one metal, the freed electrons moves through the circuit to the second plate. The original plate that had its electrons knocked out would become slightly positive, thus att...
- Sat Apr 14, 2018 6:24 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: dilution
- Replies: 4
- Views: 638
Re: dilution
I believe you would have to convert the molarity of both substances into moles, then add together the two substance's moles. Add together the liters, then divide the new moles by the new amount of liters to get the new molarity.
- Sat Apr 14, 2018 6:20 pm
- Forum: Properties of Light
- Topic: Units for wavelengths [ENDORSED]
- Replies: 6
- Views: 637
Re: Units for wavelengths [ENDORSED]
Wavelengths should be in terms of meters or nanometers. If you solve for the problem correctly, then you should be able to get meters as your units for wavelength.
- Sat Apr 14, 2018 6:18 pm
- Forum: Photoelectric Effect
- Topic: Chapter 1, Question 1.13 [ENDORSED]
- Replies: 1
- Views: 1277
Re: Chapter 1, Question 1.13 [ENDORSED]
To solve part a you must use the equation v= R(1/n^2-1/n^2) and use the formula c=v times lambda. Then include both formulas, c= R(1/2^2-1/4^2)times lambda To solve for part b you use the value you got for part a(486 nm) and classify which series that number falls under (Balmer). To solve part c you...
- Sat Apr 14, 2018 5:18 pm
- Forum: Balancing Chemical Reactions
- Topic: Whole numbers
- Replies: 7
- Views: 878
Re: Whole numbers
You cannot change a subscripts as that would change the molecule. You may be referring to a coefficient. If so, not having the coefficient as a fraction makes solving for the rest of the problem easier if we leave/make the coefficient whole numbers. If you ever have a fraction, most likely all you h...
- Sat Apr 14, 2018 5:10 pm
- Forum: Balancing Chemical Reactions
- Topic: Chemistry Background [ENDORSED]
- Replies: 4
- Views: 557
Re: Chemistry Background [ENDORSED]
You will need to understand those concepts for future chemistry classes and even 14A. My friends who are almost done with the 14 series still use those basic concepts. Not to mention those concepts will show up on our midterm and most likely our final.
- Sat Apr 14, 2018 5:07 pm
- Forum: Photoelectric Effect
- Topic: Problem 1.11 -Atomic Spectra [ENDORSED]
- Replies: 1
- Views: 217
Re: Problem 1.11 -Atomic Spectra [ENDORSED]
I may be approaching this incorrectly, but n represents the amount of energy needed to eject the electrons or the energy levels. Each of the series is part of its own spectrum and this impacts the amount of energy needed to release those electrons. The Lyman series has a greater amount of energy due...