Search found 38 matches
- Fri Jun 08, 2018 5:56 pm
- Forum: Photoelectric Effect
- Topic: Visible or measurable light
- Replies: 4
- Views: 486
Re: Visible or measurable light
I don't think we have to know this specifically. But we did learn that visible light has a wavelength of 400-700nm.
- Fri Jun 08, 2018 5:55 pm
- Forum: Sigma & Pi Bonds
- Topic: exceptions
- Replies: 2
- Views: 460
Re: exceptions
I don't think so. From what we learned in class, a double bond is always one pi bond and one sigma bond.
- Fri Jun 08, 2018 5:54 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: salt in water
- Replies: 2
- Views: 2264
Re: salt in water
He was explaining that both Na+ and Cl- in table salt does not change the pH of water. This does not apply to all types of salts.
- Wed Jun 06, 2018 11:35 pm
- Forum: Naming
- Topic: Naming on Final
- Replies: 8
- Views: 1146
Re: Naming on Final
I would try to avoid the naming problems on the homework.
- Wed Jun 06, 2018 11:33 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Tetrahedral and Square planar
- Replies: 8
- Views: 1482
Re: Tetrahedral and Square planar
Tetrahedral is when the central atom is surrounded by four bonding atoms. Square planar is when the central atom is surrounded by four bonded atoms and two lone pairs.
- Wed Jun 06, 2018 11:30 pm
- Forum: Lewis Structures
- Topic: Lowest energy lewis structure
- Replies: 5
- Views: 7048
Re: Lowest energy lewis structure
You want all formal charge to be 0 or closest to 0 when there is a charge on the molecule.
- Sat Jun 02, 2018 11:04 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Bond types
- Replies: 6
- Views: 723
Re: Bond types
They are all the same types of bonds. The different ways that there are drawn are just for the three dimensional structure.
- Sat Jun 02, 2018 11:02 am
- Forum: Lewis Structures
- Topic: d-block Lewis structures
- Replies: 3
- Views: 549
Re: d-block Lewis structures
I don't think its any different than a normal lewis structure.
- Sat Jun 02, 2018 11:01 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Naming shape
- Replies: 7
- Views: 914
Re: Naming shape
I believe the ones with lone pairs have different names for the shapes.
- Sat May 26, 2018 12:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity
- Replies: 1
- Views: 277
Re: Polarity
Could be that anions attract electrons form the cations.
- Sat May 26, 2018 12:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shapes with different types of bonds
- Replies: 3
- Views: 422
Shapes with different types of bonds
I know that the shapes are still the same when you have single, double or triple bonds, but do the bond angles change when the types of bonds are different?
- Sat May 26, 2018 12:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Remembering Bond Angles
- Replies: 4
- Views: 626
Re: Remembering Bond Angles
Yes, I think you should know the bond angles associated with each shape.
- Tue May 22, 2018 9:20 pm
- Forum: Dipole Moments
- Topic: Topics on Test 3
- Replies: 2
- Views: 400
Topics on Test 3
Are dispersion forces, induced dipole-induced dipole, London forces on test 3?
- Wed May 16, 2018 10:42 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Reducing formal charge number
- Replies: 3
- Views: 845
Re: Reducing formal charge number
To reduce formal charges it is effective to move lone pairs and bonds around while continuously checking the formal charge, so it can be closest to 0. You should definitely look at formal charges in every problem that you do.
- Wed May 16, 2018 10:38 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: How to determine molecular shape
- Replies: 5
- Views: 689
Re: How to determine molecular shape
I don't think we learned this in lecture yet but I think its based on the number of bonds and what type of bonds there are.
- Wed May 16, 2018 10:37 am
- Forum: Ionic & Covalent Bonds
- Topic: Naming Molecules
- Replies: 5
- Views: 595
Naming Molecules
Do we need to know how to name molecules or determine molecules based on their names for exam 3 or the final?
- Sat May 12, 2018 1:45 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Calculating formal charges
- Replies: 5
- Views: 1124
Re: Calculating formal charges
The formal charge for each element is:
FC = VE (valence electrons) - LPE (lone pair electrons) - 0.5BE (half the bonding electrons).
Hope this helped.
FC = VE (valence electrons) - LPE (lone pair electrons) - 0.5BE (half the bonding electrons).
Hope this helped.
- Sat May 12, 2018 1:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: "1.20A or 1.40A"
- Replies: 2
- Views: 315
Re: "1.20A or 1.40A"
I don't think we have to know how to calculate bonds lengths in this course.
- Sat May 12, 2018 1:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: Metals
- Replies: 4
- Views: 403
Re: Metals
They lost electrons because it is a lot easier to lose 1-2 electrons that to gain 6-7 electrons.
- Sat May 12, 2018 1:39 pm
- Forum: Octet Exceptions
- Topic: Octet fule in forming compounds
- Replies: 2
- Views: 454
Re: Octet fule in forming compounds
If calcium loses two electrons (becoming Ca^2a) it will have the structure of Argon, having eight valence electrons.
- Sat May 12, 2018 1:37 pm
- Forum: Ionic & Covalent Bonds
- Topic: Lewis Structure vs Resonance Structure
- Replies: 6
- Views: 735
Re: Lewis Structure vs Resonance Structure
Resonance structures are just different lewis structures. Lewis structures are the individual structures within the resonance structures. They are not two different things, they are integrated together.
- Wed May 09, 2018 12:02 am
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity Exceptions
- Replies: 3
- Views: 653
Electron Affinity Exceptions
Do we need to know the exceptions to the trend of electron affinity for the upcoming exam?
- Sun May 06, 2018 4:22 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Shapes of orbitals
- Replies: 6
- Views: 787
Re: Shapes of orbitals
I don't think so. I hope not.
- Sun May 06, 2018 4:21 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 4s and 3d
- Replies: 4
- Views: 480
Re: 4s and 3d
I think that it is due to the difference in n. n=4 is a higher energy level than n=3.
- Sun May 06, 2018 4:16 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 3
- Views: 462
Electron Affinity
I am having trouble understanding how energy is released or spent when you add an electron to an element. Can someone please explain this to me? I understand the trend of electron affinity and how it increases towards the right (where the elements want to become stable).
- Sun Apr 29, 2018 1:45 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: What does electron spin actually mean? [ENDORSED]
- Replies: 9
- Views: 3423
Re: What does electron spin actually mean? [ENDORSED]
Not sure, but I think for this class we just have to know that for two electrons to bond they have to spin in opposite directions.
- Sun Apr 29, 2018 1:42 pm
- Forum: Photoelectric Effect
- Topic: Test 2 #7 [ENDORSED]
- Replies: 3
- Views: 484
Re: Test 2 #7 [ENDORSED]
For this question you had to use the equation: (Energy photon - threshold energy = kinetic energy). The kinetic energy is 0 so you just do (hc)/wavelength = the given threshold energy. After plugging in variable, you can sold for wavelength which equals 2.20x10^-7 m. Hope this helped.
- Sun Apr 29, 2018 1:39 pm
- Forum: Photoelectric Effect
- Topic: What is work function? [ENDORSED]
- Replies: 15
- Views: 5745
Re: What is work function? [ENDORSED]
Work function is just a synonym for threshold energy. It is not an equation, it is the minimum energy needed for an electron to be ejected from a metal. The value is usually given.
- Sat Apr 21, 2018 4:55 pm
- Forum: Properties of Light
- Topic: test 2
- Replies: 18
- Views: 1662
Re: test 2
I think the questions will be similar to the examples we did in class and the questions we get for homework.
- Sat Apr 21, 2018 4:54 pm
- Forum: General Science Questions
- Topic: Test #2 [ENDORSED]
- Replies: 6
- Views: 910
Re: Test #2 [ENDORSED]
I would recommend doing as many practice as possible including using the calculator so you do not have trouble with time.
- Sat Apr 21, 2018 4:52 pm
- Forum: DeBroglie Equation
- Topic: DeBrogile Module
- Replies: 6
- Views: 563
Re: DeBrogile Module
It should definitely be converted. I would recommend checking your conversion factors (you should multiply by 1,000 and divide by 3,600)!
- Sun Apr 15, 2018 12:03 am
- Forum: Properties of Light
- Topic: Equations [ENDORSED]
- Replies: 8
- Views: 739
Re: Equations [ENDORSED]
I used them based on what information is given. You should almost always be given 2/3!
- Sun Apr 15, 2018 12:01 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Equations and Combustion
- Replies: 7
- Views: 1024
Re: Balancing Chemical Equations and Combustion
The products of combustion are always CO2 and H2O.
- Sun Apr 15, 2018 12:00 am
- Forum: Balancing Chemical Reactions
- Topic: How to Balance [ENDORSED]
- Replies: 5
- Views: 526
Re: How to Balance [ENDORSED]
I like to start with the easiest coefficients and then go on from there.
- Sat Apr 14, 2018 11:58 pm
- Forum: Empirical & Molecular Formulas
- Topic: Combustion Reaction [ENDORSED]
- Replies: 6
- Views: 665
Re: Combustion Reaction [ENDORSED]
The combusted element produces CO2 + H2O after reacting with oxygen.
- Sat Apr 14, 2018 11:55 pm
- Forum: Photoelectric Effect
- Topic: Dividing by Avogadro's constant [ENDORSED]
- Replies: 2
- Views: 274
Re: Dividing by Avogadro's constant [ENDORSED]
The question gave a value that was for 1 mole of an element and he asked how we can find out the value for an individual molecule. To find this you divide by Avogadro's constant because there are 6.022 x 10^23 molecular units in a mole.
- Sat Apr 14, 2018 11:52 pm
- Forum: Significant Figures
- Topic: Expected mastery of Significant Figures
- Replies: 6
- Views: 571
Re: Expected mastery of Significant Figures
I think you should figure it out how to use sig figs as soon as possible just in case!
- Sat Apr 14, 2018 11:46 pm
- Forum: SI Units, Unit Conversions
- Topic: Do we have to convert final answer to make it simpler? [ENDORSED]
- Replies: 4
- Views: 516
Re: Do we have to convert final answer to make it simpler? [ENDORSED]
I'm pretty sure either way is fine. The question might specify by asking "how many meters" and then you would put: x 10^-9.