Search found 27 matches
- Sun Jun 10, 2018 8:48 pm
- Forum: Lewis Acids & Bases
- Topic: Determining Acid Strength
- Replies: 6
- Views: 560
Re: Determining Acid Strength
The bond strength of an acid generally depends on the size of the 'A' atom: the smaller the 'A' atom, the stronger the H-A bond. HF has the strongest bond and is the weakest acid. The strong bond between the more similarly-sized HF atoms doesn't want to break and allow the H to transfer. In contrast...
- Sun Jun 10, 2018 8:39 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted vs Lewis Acids and Bases
- Replies: 5
- Views: 694
Re: Bronsted vs Lewis Acids and Bases
Bronsted defines an acid as a proton donor whereas Lewis defines an acid as an electron pair acceptor. Conversely to the Bronsted theory, a base is a proton acceptor and in Lewis theory, a base is an electron pair donor. Therefore, some molecules, which don’t possess protons, can be acids according ...
- Sat Jun 09, 2018 2:31 pm
- Forum: Lewis Acids & Bases
- Topic: Final Layout
- Replies: 2
- Views: 249
Final Layout
Does anyone know what the layout of the final is going to be? Like how much of it is going to be material after the midterm? Also, what we have to know about acids/bases and coordination compounds?
- Sun Jun 03, 2018 9:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating Ligands
- Replies: 2
- Views: 278
Re: Chelating Ligands
Chelating ligands can have several points of attachment. Ethylenediamine (NH2 CH2 CH2 NH2), can bond to a metal ion through each of the two nitrogens. Acetylacetone (CH3 COCH2 COCH3) is another example.
- Sun Jun 03, 2018 9:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Shape
- Replies: 4
- Views: 311
Re: Seesaw Shape
The image did not come out right the lone electrons were above the C as well as the two Xs.
- Sun Jun 03, 2018 9:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Shape
- Replies: 4
- Views: 311
Re: Seesaw Shape
I am a bit confused about this question. I have always assumed that the lone electron pair was above the central atom and that one element was on the right, one element was on the left, and two elements were on the bottom of the central atom. What I pictured below. This would give it the seesaw shap...
- Sun Jun 03, 2018 9:10 pm
- Forum: Hybridization
- Topic: Electron Promotion
- Replies: 2
- Views: 1305
Re: Electron Promotion
Electron promotion is when an electron absorbs a photon to jump from a low energy level orbital to a higher energy orbital, hence “promotion.” This can only happen if the photon energy matches the energy difference of the orbitals. Hybridization is the concept of mixing atomic orbitals (s and p) int...
- Sun May 27, 2018 10:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: PF3 molecular geometry
- Replies: 2
- Views: 647
PF3 molecular geometry
When drawing the Lewis structure of PF3 would there be one lone pair or a double bond? Also, do double or triple bonds matter in VSEPR?
- Sun May 27, 2018 10:32 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: structure SF4
- Replies: 2
- Views: 161
Re: structure SF4
It is because there is a lone pair around Sulfur. The electrons want to be the furthest away possible from each other which is why the lone pair is usually above the central atom with the four fluorides being less than 90-degrees from each other. The lone pair is not counted so equatorial the angle ...
- Sun May 27, 2018 10:24 pm
- Forum: Dipole Moments
- Topic: dipole moments and polarization
- Replies: 3
- Views: 226
Re: dipole moments and polarization
Do you mean it is polar because the oxygen is pulling electrons giving it a slight negative charge and the two hydrogens have a slight positive charge? Why doesn't this apply to CH4 which is to my knowledge non-polar?
- Sun May 27, 2018 10:19 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: lone pairs
- Replies: 5
- Views: 380
Re: lone pairs
In bent molecular geometry, there is a middle element with two other elements at the bottom end making a 120-degree angle. The lone pairs are straight ahead of the middle electron. When there are more than one lone pairs the angle between the two elements decrease making it <109 degrees.
- Sun May 20, 2018 11:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Stable lewis structures
- Replies: 2
- Views: 214
Re: Stable lewis structures
Do you mean the way of double or triple bonds? For example in single bonded N-N there would be 6 lone pairs for each carbon which means the formal charge would be -2. If you were to triple bond nitrogen there would be 2 lone pairs and 3 shared electrons decreasing the formal charge to zero, therefor...
- Sun May 20, 2018 10:58 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen bonds vs. dipole-dipole bonds
- Replies: 2
- Views: 191
Hydrogen bonds vs. dipole-dipole bonds
Hey guys I was wondering about the strength of the hydrogen bonds vs dipole-dipole bonds vs ion dipole bonds. Essentially which ones are stronger and harder to break.
- Sun May 20, 2018 10:52 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Shortcut
- Replies: 3
- Views: 595
Re: Formal Charge Shortcut
Its just looking at the PTOE by seeing how many valence electrons the element has and then using # of valence electrons - number of electrons in the lewis structure. For example nitrogen has 5 valence electrons so if it had 7 electrons in the lewis structure the formal charge of nitrogen would be -2.
- Sun May 13, 2018 3:52 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for NO3-
- Replies: 3
- Views: 406
Re: Lewis Structure for NO3-
Sorry, I just realized that mistake. I am still confused though because N has 5 V.e and if there were two double bonds with Oxygen then its formal charge would be zero. The single bond electron would have a formal charge of -1. The two double bond oxygens would have a formal charge of zero. Wouldnt ...
- Sun May 13, 2018 3:18 pm
- Forum: Lewis Structures
- Topic: Valence Electrons by Group
- Replies: 2
- Views: 173
Valence Electrons by Group
If an element is in group 9 such as cobalt how many valence electrons does it have? Would we assume that group 10 elements such as nickel have 0 valence electrons as well?
- Sun May 13, 2018 3:15 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for NO3-
- Replies: 3
- Views: 406
Lewis Structure for NO3-
In class, we went over the Lewis structure of NO3- and there were only 1 double bond and two single bonds connecting N to O. Could there be two double bonds and one single bond? It would make more sense because N has 7 valence electrons so with two double bonds it would have a value of +2 and one Ox...
- Thu May 03, 2018 11:34 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Filling of Orbitals [ENDORSED]
- Replies: 2
- Views: 218
Electron Filling of Orbitals [ENDORSED]
In 2.45 part b, they ask to name the element with the electron configuration of [Ar]3d^3,4s^2 which is Vanadium. My question is to why the 4s orbital was filled and put second even though it is lower in energy and is filled first. The same is for the electron configuration for Tellurium [Kr] 4d^10, ...
- Thu May 03, 2018 11:20 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configurations and Unpaired e- [ENDORSED]
- Replies: 3
- Views: 253
Electron Configurations and Unpaired e- [ENDORSED]
Hello, I am confused on how to determine the number of unpaired electrons. For example, the electron configuration for Se is [Ar] 3d^10, 4s^2, 4p^4. Because there are 4 electrons in the p-orbital doesn't that mean that all 4 are unpaired as they first go in separate shells then fill in the boxes wit...
- Sun Apr 29, 2018 11:36 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: f orbitals
- Replies: 3
- Views: 198
Re: f orbitals
The Professor said not for chem 14a
- Mon Apr 23, 2018 10:11 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 4
- Views: 294
Rydberg Equation
Can someone explain the Rydberg equation that was states in class that differs from v=R (1/ni^2-1/nf^2)?
- Mon Apr 23, 2018 9:26 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Homework Question 1.11
- Replies: 1
- Views: 120
Homework Question 1.11
In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), as shown in Figs. 1.10 and 2.1. What is common to the lines within a series that makes grouping them together logical? I am having ...
- Sun Apr 15, 2018 11:49 pm
- Forum: Empirical & Molecular Formulas
- Topic: empirical vs molecular
- Replies: 5
- Views: 454
Re: empirical vs molecular
Empirical formulas give us the basic structure of the covalently bonded molecule within the molecule. The molecular formula gives us the actual number of elements in a molecule. The Empirical formula tells us the ratio of elements in a compound which is helpful in 1. Calculating the percentage compo...
- Sun Apr 15, 2018 11:43 pm
- Forum: Significant Figures
- Topic: Zeros in Sig Figs
- Replies: 3
- Views: 430
Zeros in Sig Figs
I am a little confused on when zeros count as significant figures. I understand that in a number such as 9.00 there are three sig figs but if the number was 0.09 would 9 be the only sig fig? Also, how many sig figs would be in the number 0.0900?
- Sun Apr 15, 2018 11:34 pm
- Forum: Balancing Chemical Reactions
- Topic: Practice Worksheet Week 1 Question 3 [ENDORSED]
- Replies: 3
- Views: 333
Re: Practice Worksheet Week 1 Question 3 [ENDORSED]
Did you count 2 nitrogens and 4 oxygens because the two at the bottom of the parenthesis means you multiply with whats inside of them? There would be 2 nitrogens and 4 oxygens. The mass of nitrogen would be 28 and the mass of oxygen would be 64. I did this and got Sr= 49%, O= 36%,and N=16%.
- Sun Apr 15, 2018 1:29 pm
- Forum: Photoelectric Effect
- Topic: When photon energy is less than threshold energy
- Replies: 2
- Views: 162
Re: When photon energy is less than threshold energy
I would assume that most if not all of the energy dissipates as heat as well.
- Fri Apr 13, 2018 5:52 pm
- Forum: Photoelectric Effect
- Topic: Post module quiz #25
- Replies: 6
- Views: 217
Re: Post module quiz #25
Would it be A because c= the speed of light?