Search found 30 matches

by Dana Wilks 3I
Wed Dec 05, 2018 4:06 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: question 17.33 (sixth edition)
Replies: 1
Views: 60

question 17.33 (sixth edition)

This questions asks us whether a ligand can be polydentate. The molecule for part a is HN(CH2CH2NH2)2. While I understand that it would be a tridentate ligand because there are three nitrogen atoms each with lone pairs, are we able to assume this will always be true for nitrogen atoms? Should we be ...
by Dana Wilks 3I
Tue Dec 04, 2018 2:56 pm
Forum: Resonance Structures
Topic: Delocalization
Replies: 6
Views: 515

Re: Delocalization

I believe delocalization has to do with resonance. When we draw a lewis structure for a compound with resonance we indicate single and double bonds. In actuality the molecule doesn't have clear single or double bonds, rather it has something in between (which makes it more stable).
by Dana Wilks 3I
Tue Dec 04, 2018 2:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity
Replies: 11
Views: 174

Re: polarity

405211415 wrote: To help determine if it is polar or not find the central atom and see if the dipoles are the same on both sides .


Going off of this, to determine if the dipoles are the same or not, you can look at the electronegativity of the (different) atoms surrounding the central atom.
by Dana Wilks 3I
Wed Nov 28, 2018 11:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW Question 4.27
Replies: 4
Views: 176

Re: HW Question 4.27

Would we be expected to know the arrangement of C5H5N without being given a diagram?
by Dana Wilks 3I
Wed Nov 28, 2018 11:37 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 5
Views: 134

Re: Bond Angles

Many of the bond angles are intuitive, while others are less so and should probably be memorized. For example, the bond angles for molecules with trigonal planar shape is 120 degrees (which is just the degrees of a circle- 360 degrees- divided by 3). If there is a lone pair, then it exerts more repu...
by Dana Wilks 3I
Wed Nov 28, 2018 11:33 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent and Angular
Replies: 5
Views: 133

Re: Bent and Angular

yes, either will be accepted. Bent and angular mean the same thing and refer to molecules with trigonal planar electron arrangement with one lone pair. The general formula for these compounds is AX2E1.
by Dana Wilks 3I
Wed Nov 28, 2018 11:29 am
Forum: Naming
Topic: Coordination number
Replies: 10
Views: 378

Re: Coordination number

The number of atoms attached to the central atom, this does not include lone pairs. double bonds and triple bonds only count as 1 for example SO2 coordination number=2 Like Jocelyn said, it does not include lone pairs. On a related note, though, the steric number include the number of atoms bonded ...
by Dana Wilks 3I
Wed Nov 28, 2018 11:23 am
Forum: Dipole Moments
Topic: Polarity of Asymmetrical Molecules
Replies: 4
Views: 106

Re: Polarity of Asymmetrical Molecules

To be non polar, the molecule must be symmetric. This requires the shape to be linear, trigonal planar, and tetrahedral, which allows the net dipole moment to be zero if the atoms surrounding the central atom are the same.
by Dana Wilks 3I
Tue Nov 27, 2018 5:39 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 7
Views: 332

Re: Polarity

For example, the lewis structure for carbon dioxide has 2 lone pairs on both the oxygen atoms. To be as far away from each other as possible the two oxygen atoms are opposite each other so their dipole moments cancel out.
by Dana Wilks 3I
Tue Nov 27, 2018 5:33 pm
Forum: Bond Lengths & Energies
Topic: SO2 and SO3 bond length
Replies: 2
Views: 651

Re: SO2 and SO3 bond length

As stated above, the bond angles will be different for the two compounds. SO2 has two oxygen atoms bonded to the central sulfur atom. Because the sulfur atom does not adhere to the octet rule, it also has an additional lone pair, which repels the two oxygen atoms, giving it an electron arrangement o...
by Dana Wilks 3I
Tue Nov 27, 2018 5:21 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Drawing a Dipole
Replies: 6
Views: 115

Re: Drawing a Dipole

Yes, the arrow should point towards the partial negative charge. The textbook uses the other notation, though.
by Dana Wilks 3I
Tue Nov 27, 2018 5:20 pm
Forum: Hybridization
Topic: Regions of Electron Desnity
Replies: 5
Views: 89

Re: Regions of Electron Desnity

Yes, and they also count when determine electron arrangement. It is important however, to remember that lone pairs do not count when naming the shape.
by Dana Wilks 3I
Tue Nov 27, 2018 5:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity of non-symmetric atoms
Replies: 1
Views: 41

Polarity of non-symmetric atoms

I understand that when molecules are symmetric, the dipole moments cancel out the net effect is zero ( CCL4 for example) and when they are not symmetric (CHCl3) the dipole moments don't cancel so it's a polar molecule overall. What if the molecules surrounding a central atom were different but had e...
by Dana Wilks 3I
Tue Nov 27, 2018 5:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 3
Replies: 38
Views: 717

Re: Test 3

Does this mean that the material covered in this past Monday's lecture won't be included?
by Dana Wilks 3I
Tue Nov 27, 2018 5:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity vs. nonpolarity
Replies: 8
Views: 162

Re: polarity vs. nonpolarity

I would suggest first looking at the lewis structure and determining if it is symmetrical, this can be figured out by whether or not all the atoms surrounding the central atom are the same i.e. CCl4 I am confused about whether you should be looking at the lewis structure or the molecular geometry, ...
by Dana Wilks 3I
Thu Nov 15, 2018 11:57 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework #4.13 part a (6th edition)
Replies: 1
Views: 38

Homework #4.13 part a (6th edition)

For the I3- molecule, I understand how to draw the correct lewis structure with 3 lone pairs on the central I atom. However, because the lone pairs are not symmetrical, I am confused as to why the shape wouldn't be angular instead of linear.
by Dana Wilks 3I
Thu Nov 15, 2018 11:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework Question 4.5 (6th edition)
Replies: 2
Views: 50

Homework Question 4.5 (6th edition)

For part b on question 4.5, it asks us to predict the OClO bond angle for a ClO2 + ion. I understand that the shape is angular because of the lone pair on the Cl atom, but I don't understand how we are supposed to know that the angle will be slightly less than 120 degrees.
by Dana Wilks 3I
Wed Nov 14, 2018 11:35 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 9
Views: 216

Re: Bond Length

I believe you would need experimental data to determine the exact bond length, but you could definitely say that it would be in between the two values for single/double bonds, so in this case between 100 and 110.
by Dana Wilks 3I
Wed Nov 14, 2018 10:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Thanksgiving [ENDORSED]
Replies: 14
Views: 339

Re: Thanksgiving [ENDORSED]

He still hasn't announced if next week's Wednesday lecture will be cancelled. Hopefully we'll be ahead enough!
by Dana Wilks 3I
Wed Nov 14, 2018 5:28 pm
Forum: Administrative Questions and Class Announcements
Topic: Grades
Replies: 5
Views: 176

Re: Grades

I believe that any curve (which would only serve to help, not hurt, your grade) applied will only be determined at the end of the quarter based on the final class average. But it won't be curved in the sense that x % of the class gets A's, x % gets B's and so on.
by Dana Wilks 3I
Wed Nov 14, 2018 5:25 pm
Forum: Octet Exceptions
Topic: Resonance Structures
Replies: 7
Views: 245

Re: Resonance Structures

Is the final answer the structures with the three resonance structures with the alternating double bond for the oxygen, or do I also include the original one without the double bond that obeyed the octet rule but had a positive formal charge on the central atom? The three structures with different ...
by Dana Wilks 3I
Wed Nov 14, 2018 5:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing shape based off of lewis structure
Replies: 4
Views: 106

Re: Drawing shape based off of lewis structure

While we don't need to know how to draw the wedge and dash projections, they are helpful for understanding the 3-D visual of various molecular shapes since the lewis structures aren't necessarily accurate in that sense.
by Dana Wilks 3I
Thu Nov 08, 2018 11:37 am
Forum: Administrative Questions and Class Announcements
Topic: Type of calculator
Replies: 8
Views: 238

Re: Type of calculator

As long as it's not programmable you should be fine!
by Dana Wilks 3I
Sun Oct 21, 2018 10:38 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 139
Views: 83792

Re: Advice from a Medical Student [ENDORSED]

Thank you for the advice!
by Dana Wilks 3I
Sun Oct 21, 2018 10:36 pm
Forum: Properties of Light
Topic: Wavelengths and frequencies
Replies: 10
Views: 185

Re: Wavelengths and frequencies

Does anyone know of examples of infrared radiation? I did some research that said infrared radiation is emitted when objects are hot but not hot enough to emit visible light. This makes sense because infra red radiation in just below visible light on the EMR spectrum, with red having the lowest ene...
by Dana Wilks 3I
Sun Oct 21, 2018 10:32 pm
Forum: Properties of Light
Topic: Do I have to memorize the spectrum?
Replies: 20
Views: 390

Re: Do I have to memorize the spectrum?

I don't think you have to know specifics, but it would probably be a good idea to know the general order of the electromagnetic spectrum.
by Dana Wilks 3I
Wed Oct 10, 2018 4:32 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question G13 (Sixth Edition)
Replies: 3
Views: 176

Re: Question G13 (Sixth Edition)

Is it necessary to use the MiVi=MfVf equation? I set up this problem by using molarity=moles/liters, which gave me the number of moles (.2). I then recalculated the molarity using the new volume of 4 L to get a molarity of .05. Using .05 M and the given information that each plant was getting .1L I ...
by Dana Wilks 3I
Sun Oct 07, 2018 11:57 pm
Forum: Student Social/Study Group
Topic: HW Schedule?
Replies: 7
Views: 296

Re: HW Schedule?

I believe for this week, since we are done with high school chem review and have now started quantum material, that we should turn in homework that include problems listed from that unit (the quantum world) in the syllabus.
by Dana Wilks 3I
Sun Oct 07, 2018 11:51 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity formula
Replies: 6
Views: 253

Re: Molarity formula

I also had a question regarding the molarity formula. Is there a difference between the MiVi=MfVf formula and the Molarity= moles/volume formula? Isn't the first just derived from the latter?
by Dana Wilks 3I
Sun Oct 07, 2018 11:48 pm
Forum: SI Units, Unit Conversions
Topic: How does grading for discussion posts work?
Replies: 80
Views: 2572

Re: How does grading for discussion posts work?

Is the cutoff Friday or Sunday? For example, would this weekend's posts go towards week 1 or week 2?

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