Search found 31 matches
- Mon Jun 11, 2018 6:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-Shape
- Replies: 6
- Views: 819
Re: T-Shape
You need to consider that a T shape has different bond angles within it, they are not all identical.
- Mon Jun 11, 2018 6:54 pm
- Forum: DeBroglie Equation
- Topic: DeBroglie
- Replies: 5
- Views: 745
Re: DeBroglie
given the mass and the velocity you can use the DeBroglie equation to figure out the object in motion's wavelength. This is useful when you are attempting to figure out the wavelength of a particle or a body of mass.
- Mon Jun 11, 2018 6:48 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal bipyramidal and octahedral family [ENDORSED]
- Replies: 2
- Views: 453
Re: Trigonal bipyramidal and octahedral family [ENDORSED]
I think that we should know how to do all the VSEPR shapes that were showcased and worked through in class, and in the homework problems. Good luck (:
- Mon Jun 11, 2018 6:46 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Atom vs lone pair
- Replies: 3
- Views: 410
Re: Atom vs lone pair
lone pairs each have a negative charge, and they also have to respond to the charges of the atoms, making them push in the directions that they do push in. Think of it as a bunch of magnets of identical charges.
- Tue May 29, 2018 10:50 am
- Forum: Ionic & Covalent Bonds
- Topic: Double/Triple Bonds
- Replies: 8
- Views: 1039
Re: Double/Triple Bonds
All atoms have the capacity but it depends on the whole molecule. You want to make it as stable as possible.
- Tue May 29, 2018 10:47 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angle
- Replies: 9
- Views: 1019
Re: Bond angle
Think of the electron charge, because electron pairs are negatively charged they repel other negatively charged particles, like other electron pairs. They also repel molecules but not with the same force that they do lone pairs.
- Tue May 29, 2018 10:43 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Cancelling out dipole moments
- Replies: 3
- Views: 1014
Re: Cancelling out dipole moments
I would draw the direction of the arrows, if you look like they are positioned in obvious opposite directions, they cancel out. If it is not obvious I would draw vector diagrams like in high school physics, determine the x and y components and figure out whether or not the directions cancel the magn...
- Sun May 20, 2018 5:34 pm
- Forum: Ionic & Covalent Bonds
- Topic: Octet rule
- Replies: 17
- Views: 2417
Re: Octet rule
How do you know when atoms can break the octet rule? or which atoms can break the octet rule? These are just exceptions that need to be memorized, but I don't think we need to worry too much about them. just be familiar in general with the idea that there are atoms that do not agree with the octet ...
- Sun May 20, 2018 5:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: Which is more Ionic
- Replies: 2
- Views: 336
Re: Which is more Ionic
I googled your question and came across someone who had the same question as you back in 2011:
viewtopic.php?t=4306
I hope the replies help :)
viewtopic.php?t=4306
I hope the replies help :)
- Sun May 20, 2018 5:26 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.25 c)
- Replies: 4
- Views: 649
Re: 3.25 c)
Hydrogen can either have a charge of positive or negative 1 but since Aluminum already assumes the positive charge, you use the Hydrogen charge of 1- to construct your formula :)
- Mon May 14, 2018 11:19 am
- Forum: Photoelectric Effect
- Topic: Incoming Light [ENDORSED]
- Replies: 4
- Views: 2091
Re: Incoming Light [ENDORSED]
It is definitely UV light as proven by the Ultraviolet catastrophe.
- Mon May 14, 2018 11:15 am
- Forum: Ionic & Covalent Bonds
- Topic: VALENCE ELECTRONS [ENDORSED]
- Replies: 16
- Views: 2132
Re: VALENCE ELECTRONS [ENDORSED]
I like to use the group numbers and subtract 10 as we approach the non-metals.
- Mon May 14, 2018 11:14 am
- Forum: Lewis Structures
- Topic: Dots or lines [ENDORSED]
- Replies: 5
- Views: 733
Re: Dots or lines [ENDORSED]
I believe that it's fine to use lines since Dr. Lavelle uses dots simply to erase confusion before delving into the concept. I think moving forward we will be using the system of lines in class.
- Mon May 14, 2018 11:11 am
- Forum: Electronegativity
- Topic: Trends? [ENDORSED]
- Replies: 10
- Views: 1661
Re: Trends? [ENDORSED]
We went over atomic radius, ionic radius, ionic energy and electron affinity in class.
- Mon May 14, 2018 11:09 am
- Forum: General Science Questions
- Topic: Conceptual Questions
- Replies: 4
- Views: 679
Re: Conceptual Questions
I find it really helpful to watch videos on the concept, I like Crash Course Chemistry. I watch the video and take notes on it. It's also helpful to explain the concept to other people. If you can explain the concept without using notes you have a full understanding of the concept.
- Sun May 13, 2018 8:19 pm
- Forum: Lewis Structures
- Topic: Valence shell on Noble gases
- Replies: 4
- Views: 617
Re: Valence shell on Noble gases
No, Noble gasses have a full valence shell and do not need any electrons to become stable.
- Sun May 13, 2018 8:18 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent vs Metallic Bonds
- Replies: 6
- Views: 1364
Re: Ionic vs Covalent vs Metallic Bonds
An ionic bond is the transfer of electrons from an non-metal to a metal, a covalent bond is when two non-metals share electrons and metallic bond is when a metal exists within a mass of electrons.
- Sun May 13, 2018 8:11 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Equation
- Replies: 3
- Views: 490
Re: Equation
I would use the one we learnt in class to get my answer and use the high school one to check my answer.
- Sun May 13, 2018 8:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Returned midterms
- Replies: 1
- Views: 339
Re: Returned midterms
I believe they will be handed back in discussions either way but if you can't make it, go to either your TA's office hours or Dr. Lavelle's :)
- Wed Apr 25, 2018 8:38 am
- Forum: Properties of Light
- Topic: test 2
- Replies: 18
- Views: 1647
Re: test 2
I would put extra effort into having a full understanding of the concepts. Once you've got calculations down and have done the practice, focus more on the concept behind that calculation. There is no point in practicing redundantly if you don't understand what your calculations mean or what the foun...
- Wed Apr 25, 2018 8:33 am
- Forum: Photoelectric Effect
- Topic: Difference between photon and particle?
- Replies: 2
- Views: 423
Re: Difference between photon and particle?
A photon is a packet of energy or light whereas a particle is a subatomic unit such as electron, neutrons and protons. Also, traditionally photons do not have masses whereas particles do.
- Wed Apr 25, 2018 8:29 am
- Forum: Photoelectric Effect
- Topic: Frequency on Photoelectric Effect
- Replies: 5
- Views: 650
Re: Frequency on Photoelectric Effect
Since it's a one photon to one atom to one electron interaction increasing the number of photons (increasing the intensity) should increase the number of electrons ejected, this answers your second question. However, you need to keep in mind that different metals have different work functions and th...
- Sun Apr 22, 2018 11:40 am
- Forum: Properties of Light
- Topic: still don't uderrsatnd what a photon is [ENDORSED]
- Replies: 20
- Views: 1440
Re: still don't uderrsatnd what a photon is [ENDORSED]
I like to think of a photon as a packet of light/energy.
- Sun Apr 22, 2018 11:38 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: 1J=1kg.m^2.s^-2
- Replies: 3
- Views: 247
Re: 1J=1kg.m^2.s^-2
If you think about the equation for kinetic energy you see that Ek=(1/2)mv^2. (1/2) is a constant and has no units. Mass has units in Kg and velocity is measured in m/s. The equation asks you to square velocity and if you think about your exponent laws (m/s)^2 comes out to be m^2/s^2. This equation ...
- Sun Apr 22, 2018 11:25 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Calculating energy [ENDORSED]
- Replies: 3
- Views: 340
Re: Calculating energy [ENDORSED]
I suggest using unit cancellation or dimensional analysis to solve questions like these. You have all the equations you need and the givens required to use simple cancellation and number crunching :)
- Thu Apr 12, 2018 9:50 am
- Forum: Limiting Reactant Calculations
- Topic: Knowing if it's Limiting Reactions
- Replies: 6
- Views: 738
Re: Knowing if it's Limiting Reactions
I would just be prepared in general with a founded understanding. Also I suggest that you do all the limiting reactant questions that were "assigned" for homework :)
- Thu Apr 12, 2018 9:47 am
- Forum: Properties of Light
- Topic: HW 1.7 (speed of light) clarification
- Replies: 4
- Views: 269
Re: HW 1.7 (speed of light) clarification
I believe that the speed of light with the exact number of sig-digs preferred by Dr Lavelle is on the formula sheet given to us in tests :)
- Thu Apr 12, 2018 9:45 am
- Forum: Properties of Light
- Topic: HW 1.5 [ENDORSED]
- Replies: 7
- Views: 786
Re: HW 1.5 [ENDORSED]
To calculate anything about frequency or energy you would need to be given wavelength. This question is testing general knowledge of electromagnetic radiation. The question assumes that you know the order.
- Sun Apr 08, 2018 5:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Lecture Outlines [ENDORSED]
- Replies: 2
- Views: 317
Re: Lecture Outlines [ENDORSED]
I am sure that Dr. Lavelle will make it clear when he switched from one to the other :)
- Sun Apr 08, 2018 5:36 pm
- Forum: Limiting Reactant Calculations
- Topic: Actual Yield [ENDORSED]
- Replies: 3
- Views: 538
Re: Actual Yield [ENDORSED]
Because actual yield depends on side reactions, human error, and other experimental mishaps, it is hard with our level of understanding of chemistry to measure actual yield. As of now we have been calculating chemical problems within a very theoretical and almost perfect sphere, where reactions are ...
- Sun Apr 08, 2018 5:30 pm
- Forum: Empirical & Molecular Formulas
- Topic: Rounding atomic weight (general question) [ENDORSED]
- Replies: 8
- Views: 1081
Re: Rounding atomic weight (general question) [ENDORSED]
In the test we will be given a periodic table and I would assume that we are meant to use whatever version of the atomic mass that the table specifies :)