Search found 25 matches

by Rebekah Kaufman 1L
Tue Jun 05, 2018 5:03 pm
Forum: Hybridization
Topic: Regions of e- density: Tetrahedral vs. trigonal pyramidal
Replies: 3
Views: 127

Re: Regions of e- density: Tetrahedral vs. trigonal pyramidal

I believe that it depends on whether one or more of the regions of electron density are lone pairs. Lone pairs determine the shape so drawing the Lewis Structure would help you determine what shape it is.
(0 LP would mean tetrahedral and 1 LP would mean trigonal pyramidal)
by Rebekah Kaufman 1L
Thu May 31, 2018 11:09 am
Forum: Hybridization
Topic: List of the different shapes
Replies: 6
Views: 265

Re: List of the different shapes

In class we've done:
-trigonal planar
-tetrahedral
-trigonal bipyramidal
-octahedral
-trigonal pyramidal
-seesaw
-square planar
-linear

(based on my notes)
by Rebekah Kaufman 1L
Thu May 31, 2018 11:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Helpful Chart
Replies: 18
Views: 595

Re: Helpful Chart

Is there a way to calculate the bond angles or is it just a memorization thing?
by Rebekah Kaufman 1L
Thu May 31, 2018 9:55 am
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 4.19 part b and d
Replies: 3
Views: 164

Re: HW 4.19 part b and d

0 LP means zero lone pairs
by Rebekah Kaufman 1L
Wed May 30, 2018 9:57 pm
Forum: Resonance Structures
Topic: Resonance Review
Replies: 3
Views: 256

Re: Resonance Review

Hi, I'm in Dis 1L too so we should've had the same test. Resonance is when the position of an element in a molecule is different but it doesn't change the molecule. InkedIMG_3972_LI.jpg So on the test we were given pyruvate and switching the positions of the H won't be any different so we leave that...
by Rebekah Kaufman 1L
Wed May 30, 2018 9:33 pm
Forum: Hybridization
Topic: Hybridization
Replies: 2
Views: 122

Hybridization

I'm still having a difficult time understanding for hybridization works. Can someone please explain why hybridization happens and why its possible? For example, I just don't get how we can decide that an 2sp^3 oribital exists for ammonia (we did this example in class today).
by Rebekah Kaufman 1L
Wed May 30, 2018 9:22 pm
Forum: Ionic & Covalent Bonds
Topic: Help on 3.27
Replies: 1
Views: 142

Re: Help on 3.27

I found this website that explains it really well.
https://study.com/academy/lesson/writin ... ounds.html

This is a sort of visual representation of how I understand it:
InkedPeriodicTableWorks_LI.jpg
by Rebekah Kaufman 1L
Sun May 20, 2018 9:09 pm
Forum: Dipole Moments
Topic: Dipole going from positive to negative
Replies: 1
Views: 80

Dipole going from positive to negative

Can someone please explain why dipole movement goes from positive to negative. Thanks.
by Rebekah Kaufman 1L
Sun May 20, 2018 8:55 pm
Forum: Lewis Structures
Topic: Chapter 3 homework #33
Replies: 1
Views: 99

Re: Chapter 3 homework #33

I believe it has to do with formal charges. If N forms a double bond with F then both have a +1 charge.
IMG_3919.jpg
by Rebekah Kaufman 1L
Sun May 20, 2018 3:00 pm
Forum: Lewis Structures
Topic: 3.55
Replies: 6
Views: 174

Re: 3.55

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Capture1.PNG (6.78 KiB) Viewed 171 times
According to the textbook, "Species having electrons with unpaired spins are called radicals." You can determine whether a molecule is a radical by drawing out the Lewis structure I think. The dot next to the molecule represents the unpaired spin.
by Rebekah Kaufman 1L
Sun May 13, 2018 11:36 pm
Forum: Resonance Structures
Topic: Number of Resonance Strucutres
Replies: 3
Views: 183

Number of Resonance Strucutres

Is there a way to know how many possible resonance structures a molecule will have? Or is drawing them the only way to figure that out?
by Rebekah Kaufman 1L
Sun May 13, 2018 11:19 pm
Forum: Ionic & Covalent Bonds
Topic: VALENCE ELECTRONS [ENDORSED]
Replies: 16
Views: 567

Re: VALENCE ELECTRONS [ENDORSED]

Miranda Hughes 1F wrote:You just look at the periodic table and count what position the element is in in the row (excluding d block). For example: Oxygen has 6 valence electrons and Flourine has 7 and Carbon has 4 valence electrons.


Why is the d block excluded when counting valence electrons?
by Rebekah Kaufman 1L
Wed May 09, 2018 10:37 pm
Forum: Empirical & Molecular Formulas
Topic: Question 3 on midterm [ENDORSED]
Replies: 8
Views: 489

Re: Question 3 on midterm [ENDORSED]

Hi, I also had a hard time figuring out this problem. When I checked my answer afterwards I got the correct molecular formula. I tried to explain it to a friend and came up with these pictures. I have absolutely no idea if I went about solving the problem the right way, but I thought I'd sort of sho...
by Rebekah Kaufman 1L
Wed May 02, 2018 5:30 pm
Forum: Significant Figures
Topic: Use of Appropriate Sig Figs
Replies: 2
Views: 247

Re: Use of Appropriate Sig Figs

You are correct. When given two numbers with different sig figs, you use the smaller sig fig for your own answer.
by Rebekah Kaufman 1L
Wed May 02, 2018 5:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: hw qs 2.19
Replies: 1
Views: 66

Re: hw qs 2.19

Values of l:
0=s; 1=p; 2=d; 3=f; 4=g
If you're looking at an electron in a 6d-subshell, then the d tells you that your l=2. And yes, you do use the ml=l,(l-1),...-l to find the ml values.
by Rebekah Kaufman 1L
Tue May 01, 2018 8:27 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.43
Replies: 7
Views: 2491

Re: 2.43

I think silver is treated as a special case, just like Chromium. Filling the oribitals to d^5 and d^10 make elements more stable. In the case of chromium, when it looks like it should be [Ar]3d^4s^2, it becomes [Ar]3d^54s^1.
by Rebekah Kaufman 1L
Sun Apr 29, 2018 11:31 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: HELP hw problem 2.17 [ENDORSED]
Replies: 5
Views: 139

Re: HELP hw problem 2.17 [ENDORSED]

You can get (-2,-1,0,1,2) from l=2 because as the textbook says, "There are 2l +1 different values of m for a given value of l." This means that when l=2 there will be a total of 5 possible m values. We also learned that m=l,l-1,...-l. This basically means that m can be +l and -l and every...
by Rebekah Kaufman 1L
Wed Apr 25, 2018 9:40 pm
Forum: Quantum Numbers and The H-Atom
Topic: Fourth Quantum Number
Replies: 5
Views: 201

Fourth Quantum Number

Do we always need to calculate the fourth quantum number or do we only need to specify it if specifically asked?
by Rebekah Kaufman 1L
Wed Apr 25, 2018 9:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration of Ag
Replies: 3
Views: 527

Electron Configuration of Ag

I know we haven't gone over this in class yet, but why is the electron configuration of silver [Kr]4d^10 5s^1 instead of [Kr]4d^9 5s^2?
by Rebekah Kaufman 1L
Sun Apr 22, 2018 11:14 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: HW 1.27
Replies: 2
Views: 169

Re: HW 1.27

To calculate the number of photons, you divide the overall energy generated by the energy per photon.
J / ( J/photon)
The joules cancel out leaving you with the amount of photons emitted.
by Rebekah Kaufman 1L
Sun Apr 22, 2018 10:52 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 4
Views: 204

Work Function

In most of the problems I've seen, the work function always seems to be something given, is it ever something that we will need to calculate ourselves? If we do calculate it ourselves, do convert our answer from joules to electron-volts?
by Rebekah Kaufman 1L
Sun Apr 22, 2018 10:35 pm
Forum: Properties of Electrons
Topic: Wave Properties: Constructive and Destructive Interference
Replies: 2
Views: 211

Wave Properties: Constructive and Destructive Interference

I know that constructive interference of wave particles causes the amplitude of the combined waves to increase and that in the case of destructive interference, the amplitude decreases, but I am confused about what the significance of the changes in amplitude mean. I'd appreciate it if someone could...
by Rebekah Kaufman 1L
Sat Apr 14, 2018 10:33 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electron Energy Levels
Replies: 3
Views: 139

Electron Energy Levels

Why, as electron energy levels (n) increase, does the amount of energy between the energy levels decrease? (Ex. it takes more energy to go from n=2 to n=1 thanto go from n=4 to n=2)
by Rebekah Kaufman 1L
Sat Apr 14, 2018 10:20 pm
Forum: Molarity, Solutions, Dilutions
Topic: Percentage of Solution Molarity Problem
Replies: 1
Views: 613

Percentage of Solution Molarity Problem

My TA gave us a worksheet with different problems and one was: Wine is approximately 12% ethanol (CH3CH2OH) by volume. Ethanol has a molar mass of 46.06 g/mol and a density 0.789 g/mL. How many moles of ethanol are present in a 750-mL bottle of wine? I understand how to calculate the moles, but in r...
by Rebekah Kaufman 1L
Thu Apr 12, 2018 11:28 pm
Forum: Photoelectric Effect
Topic: Kinetic Energy
Replies: 2
Views: 115

Kinetic Energy

I am confused about what it means ejected electrons to have zero kinetic energy because if they're being ejected doesn't that mean that they've moved and would therefore have kinetic energy?

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