## Search found 38 matches

Fri Jun 08, 2018 5:56 pm
Forum: Photoelectric Effect
Topic: Visible or measurable light
Replies: 4
Views: 201

### 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: 233

### 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: 227

### 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: 552

### 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: 689

### 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: 3063

### 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: 271

### 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: 280

### 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: 390

### 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: 148

### 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: 206

### 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: 309

### 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: 147

### 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: 306

### 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: 323

### 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: 217

### 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: 328

### 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.
Sat May 12, 2018 1:43 pm
Forum: Ionic & Covalent Bonds
Topic: "1.20A or 1.40A"
Replies: 2
Views: 122

### 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: 198

### 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: 209

### 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: 262

### 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: 321

### 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: 438

### 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: 266

### 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: 254

### 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: 1189

### 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: 228

### 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: 3253

### 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: 867

### 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: 609

### 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: 321

### 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: 307

### 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: 499

### 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: 240

### 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: 322

### 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: 134

### 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: 342

### 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: 291

### 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.