Search found 32 matches
- Mon Jun 11, 2018 11:00 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Strength of Acid and Bases
- Replies: 3
- Views: 464
Re: Strength of Acid and Bases
when something is referred to as "less acidic" it's usually talking about the pH of something rather than the actual strength of the acid but a weak acid would cause little change in pH of a solution or make something acidic. An acid is strong when the pKA is lower and is weaker when the p...
- Sun Jun 10, 2018 8:09 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma vs Pi Bonds
- Replies: 4
- Views: 641
Re: Sigma vs Pi Bonds
I think it has to do more with the number of bonds. So a single bond is a sigma bond, a double is a sigma and pi bond, and a triple is one sigma and two pi bonds.
- Sun Jun 10, 2018 8:07 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Homework Problem 17.33.)
- Replies: 4
- Views: 630
Re: Homework Problem 17.33.)
H2O is a monodentate because even though it has two lone pairs, only one of those will bind and the other one won't because it has no way of biding to the central atom since it's on the oxygen with the other lone pair that is already bound. Basically, the positions of the lone pairs won't allow it t...
- Sun Jun 10, 2018 8:03 pm
- Forum: Hybridization
- Topic: pi bond and sigma bond
- Replies: 3
- Views: 483
Re: pi bond and sigma bond
Vivian Gonzalez 1A wrote:What do we need to know about pi and sigma bonds for the final?
I would say know what they each represent and also how many of each make up a single, double, and triple bond.
- Thu Jun 07, 2018 11:23 pm
- Forum: Amphoteric Compounds
- Topic: Identifying an amphoteric compound
- Replies: 3
- Views: 2925
Re: Identifying an amphoteric compound
what we did in discussion was create an equilibria where we used the amphoteric compound with water and tried to see if we could use it as both an acid and a base. The example we did was H2PO3- : using it as an acid = H2PO3- + H2O ⇌ (HPO3)2- + H3O+ using it as a base = H2PO3- + H2O ⇌ H3PO3 + OH- so,...
- Wed Jun 06, 2018 1:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Bonds vs Covalent Bonds
- Replies: 7
- Views: 693
Re: Ionic Bonds vs Covalent Bonds
I think that's because in Bio we talked about how covalent bonds can't be broken in water but ionic bonds can.
- Sun Jun 03, 2018 6:24 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Naming Structures
- Replies: 8
- Views: 1010
Re: Naming Structures
you could either memorize the VSEPR formulas and their shapes or you could draw the lewis structure and figure out the shape based on its number of bonds and lone pairs.
- Sun Jun 03, 2018 6:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: How To Know When A Molecule Will Be Bent?
- Replies: 4
- Views: 4896
Re: How To Know When A Molecule Will Be Bent?
You would know the molecule is bent if it has any lone pairs. In the case of water, although it has two bonds that are connected to the H, it also has two lone pairs which push down on the two bonds and make a "bent" shape rather than it being linear.
- Thu May 31, 2018 1:38 pm
- Forum: Sigma & Pi Bonds
- Topic: Double bond with 2 pi bonds?
- Replies: 2
- Views: 444
Re: Double bond with 2 pi bonds?
I don't think so, I think a double bond is always 1 sigma and 1 pi bond
- Mon May 28, 2018 2:32 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Meaning
- Replies: 5
- Views: 968
Re: Formal Charge Meaning
Formal charge is the charge assigned to an atom in a molecule which is why when the molecule has no charge, the formal charges of the individual atoms must equal zero when added up.
- Tue May 22, 2018 10:53 pm
- Forum: Lewis Structures
- Topic: Radical HW 3.59
- Replies: 6
- Views: 777
Re: Radical HW 3.59
that's a good question, I also thought we always use formal charge in a scenario like this
- Tue May 22, 2018 9:54 pm
- Forum: Lewis Structures
- Topic: hwk problem 3.37
- Replies: 1
- Views: 293
Re: hwk problem 3.37
yeah that's right!
- Sun May 20, 2018 6:03 pm
- Forum: Lewis Structures
- Topic: Where to put double bonds? [ENDORSED]
- Replies: 3
- Views: 432
Re: Where to put double bonds? [ENDORSED]
you would probably have to check the formal charges and see which position for the double bonds creates fewer formal charges
- Wed May 16, 2018 10:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: Question 3.11
- Replies: 1
- Views: 306
Question 3.11
The question asks which M3+ ions (where M is a metal) are predicted to have the following ground-state electron configurations:
a.) [Ar]3d6
b.) [Ar]3d5
The solutions manual says a is Co3+ and b is Fe3+ but could someone explain how they got this answer?
Thanks!
a.) [Ar]3d6
b.) [Ar]3d5
The solutions manual says a is Co3+ and b is Fe3+ but could someone explain how they got this answer?
Thanks!
- Sun May 13, 2018 11:39 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions [ENDORSED]
- Replies: 3
- Views: 498
Re: Exceptions [ENDORSED]
I think it's because a half full and full orbital are more stable than partially filled d orbital so the electron from 4s goes to 3d.
- Tue May 08, 2018 1:01 pm
- Forum: Trends in The Periodic Table
- Topic: Octets and ionization energy
- Replies: 2
- Views: 371
Re: Octets and ionization energy
Ionization energy is the energy needed to remove an electron from an atom. The trend for ionization energy is that it decreases down a group and increases across a period. So it's harder to remove an electron of an atom that has octet e- (8 valence electrons) because it's fully occupied (stable) and...
- Mon May 07, 2018 8:31 pm
- Forum: Lewis Structures
- Topic: Ammonium Sulfate Example in Notes
- Replies: 2
- Views: 351
Re: Ammonium Sulfate Example in Notes
To figure out the valence electrons of an elements just count across the periodic tables from the left to the right starting with one and ending with eight. So all the elements in group 1 have one valence electron like H, Li, and Na. N has 5 valence electrons because when you start counting from Li,...
- Sun May 06, 2018 8:37 pm
- Forum: SI Units, Unit Conversions
- Topic: formula units [ENDORSED]
- Replies: 69
- Views: 32367
Re: formula units [ENDORSED]
Yeah I had the same question but I think it just means number of atoms.
- Sun May 06, 2018 2:30 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Switching 3d and 4s
- Replies: 6
- Views: 1234
Re: Switching 3d and 4s
When d is occupied by electrons then it becomes lower in energy than s which is when you would put it before s. So elements with 21 electrons or more would have the d come before the s because this is when we first see d become occupied by electrons.
- Tue May 01, 2018 6:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Review Sessions [ENDORSED]
- Replies: 3
- Views: 396
Re: Review Sessions [ENDORSED]
I was wondering the same thing cause on some of the days my classes conflict with the review sessions planned
- Fri Apr 27, 2018 12:58 pm
- Forum: DeBroglie Equation
- Topic: 1.33 using De Broglie
- Replies: 3
- Views: 427
Re: 1.33 using De Broglie
for part A you're supposed to find the wavelength of the ejected electron so you would use the De Broglie formula which is wavelength = h/m * V and sub in the numbers (6.626 x 10^-34 J*s)/(9.11x10^-31 kg)(3.6 x 10^6 m/s) which gets you 2.02 x 10^-10 m or 202 pm. h is a constant and so is the mass of...
- Wed Apr 25, 2018 8:38 pm
- Forum: Photoelectric Effect
- Topic: Calculating kinetic energy of an emitted electron [ENDORSED]
- Replies: 3
- Views: 714
Re: Calculating kinetic energy of an emitted electron [ENDORSED]
yes the mass is a constant and is on the cover page of the tests so you don't have to worry about memorizing it.
- Tue Apr 24, 2018 3:19 pm
- Forum: Properties of Light
- Topic: Rydberg Formula for Atomic Hydrogen [ENDORSED]
- Replies: 4
- Views: 913
Re: Rydberg Formula for Atomic Hydrogen [ENDORSED]
The one on my cover of test 1 is -(hR/n^2), which is the same as the one given in lecture.
- Tue Apr 17, 2018 11:26 pm
- Forum: Properties of Light
- Topic: units for frequency and wavelength [ENDORSED]
- Replies: 9
- Views: 701
Re: units for frequency and wavelength [ENDORSED]
proper unit for frequency is Hertz (Hz) which is cycles per second (s^-1) and for wavelength it's usually m (or nm) but it depends on the question because it can ask for the wavelength in a particular unit.
- Tue Apr 17, 2018 2:38 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: HW Question 1.25
- Replies: 1
- Views: 115
Re: HW Question 1.25
3.37 x 10^-19 J is the answer to part (a) of the problem, it's the energy of an excited sodium atom when it generates a photon. It's then used to figure out the energy of the 5.00 mg of sodium atoms and 1 mole of sodium emitting light at the given wavelength for part (b) and (c).
- Mon Apr 16, 2018 4:02 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Frequency if energy goes from n=2 to n=4
- Replies: 6
- Views: 560
Frequency if energy goes from n=2 to n=4
So today in lecture we talked about how when the electron goes from n=4 to n=2 the change in energy would be negative and so in return the energy of the photon emitted is positive so in return the frequency is positive. But, if the electron goes from n=2 to n=4 then the change in energy will be posi...
- Sat Apr 14, 2018 10:18 pm
- Forum: Properties of Light
- Topic: wavelength description [ENDORSED]
- Replies: 11
- Views: 1180
Re: wavelength description [ENDORSED]
The amplitude of a wave is its height, but I also remember Dr. Lavelle saying how as the amplitude increases then the energy or intensity of the wave also increases. He compared it to a wave at the beach saying that a taller wave will be more powerful than a shorter wave.
- Fri Apr 13, 2018 12:57 pm
- Forum: Limiting Reactant Calculations
- Topic: M.2 Example in Textbook
- Replies: 1
- Views: 305
Re: M.2 Example in Textbook
I was wondering the same thing, I thought they might be typos?
- Tue Apr 10, 2018 5:05 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.11 / Volumes for Solutions
- Replies: 2
- Views: 324
Re: G.11 / Volumes for Solutions
For this question you don't need to know the final volume since you are given the final mole which is 0.0045 mol C6H12O6 so you can set up your equation as 0.728 M (M=mol x L^-1) x V = 0.0045 mol and to get the initial volume you would divide both sides by 0.728 mol x L^-1 which equals 6.18 x 10^-3 L.
- Mon Apr 09, 2018 10:32 pm
- Forum: Properties of Light
- Topic: Homework? [ENDORSED]
- Replies: 10
- Views: 1019
Re: Homework? [ENDORSED]
I think it's personal preference, as long as we've gone over the material then you should be fine.
- Mon Apr 09, 2018 10:29 pm
- Forum: Properties of Light
- Topic: Frequency vs Cycle
- Replies: 5
- Views: 668
Re: Frequency vs Cycle
I can't remember exactly what Dr. Lavelle said in class, but one cycle per second is a 1 Hertz which equals the frequency. So if there are 2 cycles in one second then the frequency is 2 hertz.
- Sun Apr 08, 2018 5:12 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity formula
- Replies: 6
- Views: 555
Re: Molarity formula
I think as long as you are given three of those things from the formula then you can use it. You might even be given the mole rather than M or V which you can substitute in place of MiVi since n(moles)=MV