Search found 31 matches

by ErinKim1I
Sun Jun 10, 2018 6:45 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures on the Final Exam
Replies: 5
Views: 237

Re: Drawing Lewis Structures on the Final Exam

I'm not sure if bond angles really matter for a lewis structure... I was told that they are important mostly for VSEPR, b/c that represents a 3D space.
by ErinKim1I
Sun Jun 10, 2018 6:41 pm
Forum: Naming
Topic: Coordination number
Replies: 10
Views: 379

Re: Coordination number

Just to add, coordination number typically applies to compounds with a transition metal as the central atom, so it isn't likely that you would encounter a double or triple bond in the first place.
by ErinKim1I
Sun Jun 10, 2018 6:40 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Drawing coordination compounds
Replies: 2
Views: 119

Drawing coordination compounds

Does anyone know if drawing coordination compounds will be a topic on the final? I know a couple topics regarding coordination compounds were taken out so I am just wondering. Thanks.
by ErinKim1I
Sat Jun 02, 2018 11:24 am
Forum: Hybridization
Topic: Textbook 4.37
Replies: 3
Views: 136

Re: Textbook 4.37

P has 4 areas of electron density because P has 3 bonding pairs AND a lone pair. Lone pairs are represented by both spin up and spin down.
so the answer is sp3 with the 3s orbital containing both a spin up and spin down, and the 3p orbital having 3 unpaired e-.
by ErinKim1I
Sat Jun 02, 2018 11:18 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Naming shape
Replies: 7
Views: 253

Re: Naming shape

When a question asks for molecular shape, you have to take into account the number of areas of electron density, lone pairs, etc., not just the number of atoms.
by ErinKim1I
Sat Jun 02, 2018 10:33 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination number vs. oxidation number [ENDORSED]
Replies: 4
Views: 345

Re: coordination number vs. oxidation number [ENDORSED]

I think coordination number is the number of immediate atoms surrounding a central atom whereas oxidation number is the number assigned to an atom to represent the # of electrons lost or gained
by ErinKim1I
Sun May 27, 2018 12:41 pm
Forum: Hybridization
Topic: Hybrid Orbitals
Replies: 4
Views: 168

Re: Hybrid Orbitals

How do you know when hybridization is necessary/ takes place?
by ErinKim1I
Sun May 27, 2018 12:38 pm
Forum: Resonance Structures
Topic: Clarifying wording
Replies: 2
Views: 251

Clarifying wording

Is being "more likely to contribute to a resonance structure" the same as being the best/ most stable resonance structure?
by ErinKim1I
Sun May 27, 2018 12:25 pm
Forum: Bond Lengths & Energies
Topic: 3.85 part b
Replies: 3
Views: 214

Re: 3.85 part b

When there is resonance, electrons are delocalized and so the bond length distribution is somewhere between the single and double bond in the structure.
by ErinKim1I
Wed May 16, 2018 11:29 am
Forum: Octet Exceptions
Topic: Concept of Exceptions
Replies: 4
Views: 193

Re: Concept of Exceptions

I think about it this way: s-orbitals can hold 2 e- p-orbitals can hold 6 e- so s and p together can hold 8e-, which is an octet. But starting from row 3 of the periodic table, there is a d-orbital, and d-orbitals can hold up to 10e-. So if an element has s, p, and d orbitals, the electrons in the d...
by ErinKim1I
Wed May 16, 2018 11:25 am
Forum: Octet Exceptions
Topic: Radicals [ENDORSED]
Replies: 6
Views: 358

Re: Radicals [ENDORSED]

Or if you look at the lewis structure an see an electron attached that is not in a pair, you can conclude that the structure is a radical.
by ErinKim1I
Wed May 16, 2018 11:23 am
Forum: Ionic & Covalent Bonds
Topic: Electron affinity [ENDORSED]
Replies: 6
Views: 209

Re: Electron affinity [ENDORSED]

I think the reason you are confused is because you have an incorrect definition of electron affinity. Since electron affinity is how much an element "wants" an electron, it only makes sense that the more an element wants an electron, the harder (greater energy) it will take to take an elec...
by ErinKim1I
Wed May 09, 2018 2:03 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Unicorn Practice Midterm #8
Replies: 3
Views: 302

Re: Unicorn Practice Midterm #8

I keep getting 10^-31 instead of 10^-32, can someone help me figure out where I went wrong?

I converted the g to kg and made sure I used the right units..
by ErinKim1I
Wed May 09, 2018 1:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ni3+
Replies: 3
Views: 1439

Re: Ni3+

Nevermind, I got it
by ErinKim1I
Wed May 09, 2018 1:53 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ni3+
Replies: 3
Views: 1439

Ni3+

Hi,

Can someone explain to me why the electron configuration of Ni3+ is [Ar] 3d^7, without the 4s orbitals filled up?

Thanks
by ErinKim1I
Wed May 09, 2018 11:32 am
Forum: Trends in The Periodic Table
Topic: Zeff HW 2.37
Replies: 2
Views: 157

Zeff HW 2.37

2.37 asks: True or False? Zeff for an electron in a p-orbital is lower than for an electron in an s-orbital in the same shell. The statement is true, but I'm confused because I thought that as you go across a group (which would have the same shell), Zeff increases. Can someone explain where I went w...
by ErinKim1I
Sun May 06, 2018 10:38 am
Forum: *Particle in a Box
Topic: Relationship to Schrodinger's Equation
Replies: 1
Views: 392

Relationship to Schrodinger's Equation

How does a particle in a box model Schrodinger's equation? In another post, it said that this model explains energy quantization since the box has infinitely high walls. Wouldn't there need to be a discrete amount of energy needed to pass the walls? Or does this model explain quantization in that th...
by ErinKim1I
Sun May 06, 2018 10:31 am
Forum: *Shrodinger Equation
Topic: Schrodinger's Equation & Orbitals
Replies: 3
Views: 195

Schrodinger's Equation & Orbitals

Can someone give me a basic rundown of how we use Schrondinger's equation to understand orbitals? I know we don't have to know the equation in depth but I am confused on the general relationship between the equation and orbitals.
by ErinKim1I
Sun May 06, 2018 10:28 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Switching 3d and 4s
Replies: 6
Views: 300

Switching 3d and 4s

Even though d has a higher energy than s, I was told that for some configurations you have to switch 3d to be in front of 4s. When is this the case?
by ErinKim1I
Wed Apr 25, 2018 7:56 pm
Forum: Photoelectric Effect
Topic: Calculating kinetic energy of an emitted electron [ENDORSED]
Replies: 3
Views: 239

Re: Calculating kinetic energy of an emitted electron [ENDORSED]

the mass of an electron is a constant (9.11x 10^-31 kg).
by ErinKim1I
Wed Apr 25, 2018 1:43 pm
Forum: DeBroglie Equation
Topic: Ek= 0 [ENDORSED]
Replies: 3
Views: 183

Ek= 0 [ENDORSED]

What are some situations where you have to set Ek to 0?
by ErinKim1I
Tue Apr 24, 2018 11:21 am
Forum: DeBroglie Equation
Topic: When to use DeBroglie or Ek equation
Replies: 7
Views: 300

Re: When to use DeBroglie or Ek equation

It all depends on what the question is asking. For example, if the question asks for the wavelength given mass and velocity, then you use the debroglie equation. if the question asks for KE or the maximum energy of electrons you use the Ek equation.
by ErinKim1I
Sat Apr 21, 2018 10:28 am
Forum: Einstein Equation
Topic: Different equations
Replies: 4
Views: 206

Re: Different equations

What I found helpful is realizing that in certain situations, the energy of the photon (E=hv) is equivalent to the work function. Instead of trying to figure out the work function, I simply use the Einstein equation. But this is only in particular cases.
by ErinKim1I
Sat Apr 21, 2018 10:22 am
Forum: DeBroglie Equation
Topic: Ch.1 #41 [ENDORSED]
Replies: 6
Views: 468

Re: Ch.1 #41 [ENDORSED]

Yes, you have to convert picometers to meters because m is the standard SI unit
by ErinKim1I
Wed Apr 18, 2018 11:31 am
Forum: DeBroglie Equation
Topic: HW 1.33
Replies: 12
Views: 454

HW 1.33

The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 x 10^3 km/s. Part B says: No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50 x 10^16 Hz. How much energy is required to remove the electron from the metal surf...
by ErinKim1I
Wed Apr 11, 2018 7:49 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula
Replies: 3
Views: 204

Re: Empirical Formula

Once you balanced the equation, just find % mass of each element, convert mass to mol, divide each element's # moles by the smallest # mol,make sure you get whole numbers or otherwise multiply to get a whole number, and the numbers you get are the ratios for the empirical formula.
by ErinKim1I
Wed Apr 11, 2018 7:45 pm
Forum: Limiting Reactant Calculations
Topic: M.11
Replies: 8
Views: 339

Re: M.11

(b) take the number of moles of oxygen gas you initially have and subtract it by the moles of O2 used in the first equation to produce P4O6. you should have about .0405 mol O2 for the second equation. Use that number to calculate how many grams of P4O10 you would be able to produce in the second equ...
by ErinKim1I
Wed Apr 11, 2018 7:37 pm
Forum: Properties of Light
Topic: HW 1.3 [ENDORSED]
Replies: 12
Views: 458

HW 1.3 [ENDORSED]

Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. (a) The speed of the radiation decreases. (b) The wavelength of the radiation decreases. (c) The extent of the change in the electrical field at a given point decreases. (d) The energy o...
by ErinKim1I
Tue Apr 10, 2018 4:14 pm
Forum: Limiting Reactant Calculations
Topic: Mass of Products VS. Mass of Reactants- Class Assessment
Replies: 5
Views: 239

Re: Mass of Products VS. Mass of Reactants- Class Assessment

I think this question is just testing if you understand law of conservation of mass, so I think the answer should be no.
by ErinKim1I
Mon Apr 09, 2018 4:09 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Equations With Rational Coefficients [ENDORSED]
Replies: 3
Views: 129

Re: Balancing Equations With Rational Coefficients [ENDORSED]

If he used a fraction w/ denominator 2, he probably multiplied the entire equation by 2 to create whole numbers afterwards
by ErinKim1I
Mon Apr 09, 2018 4:06 pm
Forum: Limiting Reactant Calculations
Topic: M19 - Combustion Analysis
Replies: 2
Views: 136

Re: M19 - Combustion Analysis

Find the moles of C, H, N, and O as these are the elements in caffeine. Then, divide by the smallest coefficient to get the EF. Divide the given molar mass of caffeine by the molar mass of the EF to get the ratio. multiply the resulting number by the EF to get the MF. To write the equation: MF of ca...

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