Search found 58 matches
- Sun Dec 09, 2018 3:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 513746
Re: Saying Thank You to Dr. Lavelle
Thank you Dr. Lavelle! You explained each topic so well I was able to really understand the material logically and how they come together despite not having taken chemistry in high school. You certainly made Chemistry interesting, Thank you prof! :)
- Sun Dec 09, 2018 12:45 am
- Forum: Naming
- Topic: From today's review session naming en [ENDORSED]
- Replies: 1
- Views: 506
From today's review session naming en [ENDORSED]
one of the examples was [Mn(en)2(NH3)2I2]+2
I'm a bit confused because I thought en is a shorthand for ethylenediamine which already includes (NH3)2 ? Why should there still be (NH3)2 in the formula in it is already shorthanded as en?
Please help!
I'm a bit confused because I thought en is a shorthand for ethylenediamine which already includes (NH3)2 ? Why should there still be (NH3)2 in the formula in it is already shorthanded as en?
Please help!
- Sat Dec 08, 2018 10:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw and t shape angles
- Replies: 2
- Views: 731
Seesaw and t shape angles
For seesaw, the bonds in the axial plane are <90 degrees right? How about the bonds in the equatorial planes, are those 120 degrees apart or <120 ? For T-shape, are 2 bonds in the axial plane are <90 degree? Would they be even less than the axial plane bonds in seesaw since there are 2 lone pairs pu...
- Sat Dec 08, 2018 8:44 pm
- Forum: Lewis Acids & Bases
- Topic: SO3 acid or base?
- Replies: 2
- Views: 4085
Re: SO3 acid or base?
I also want to know this as well if anyone knows please explain
- Sat Dec 08, 2018 12:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: t shape vs trigonal bipyramidal
- Replies: 1
- Views: 453
t shape vs trigonal bipyramidal
Does anyone know why AX3E2 is t shape instead of trigonal bipyramidal? That is, why are the 2 lone pairs on the equatorial plane and not on opposite sides of the axial plane? Since lone pair-lone pair e- repulsion is the strongest, wouldn't it make more sense for the 2 lone pairs to be as far from o...
- Sat Dec 08, 2018 12:11 am
- Forum: Lewis Acids & Bases
- Topic: 6A.15
- Replies: 2
- Views: 345
Re: 6A.15
I am also confused about this. If anyone knows why the answer for So2 lewis isnt the one with 2 double bonds on oxygen please explain the reason!
- Fri Dec 07, 2018 10:52 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: determining the strongest acid
- Replies: 2
- Views: 1887
determining the strongest acid
We learned 2 rules that tell us an acid is strong— 1. Weaker [longer] bonds = stronger acid because loses H+ easier 2. Resulting anion must be stable i.e. resonance or high electronegativity pulls the - charge to it and away from H+. How do we know which rule to to apply if an acid have a stronger b...
- Thu Dec 06, 2018 9:56 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: S orbitals lower energy than p orbitals
- Replies: 2
- Views: 2792
S orbitals lower energy than p orbitals
Why do electrons in the s orbitals have lower energy than those in the p orbital if the e- in s orbital shield the nuclear pull from those in p. Why do the e- in p orbitals have more energy if it experiences less nuclear attachment/pull since they are further from the nucleus and are shielded? Is it...
- Thu Dec 06, 2018 4:28 pm
- Forum: DeBroglie Equation
- Topic: Test 2 confusion
- Replies: 1
- Views: 560
Test 2 confusion
Can someone explain why these 2 answers are wrong?
The first picture is 3b. Kinetic energy is 2x10^-19
The first picture is 3b. Kinetic energy is 2x10^-19
- Mon Dec 03, 2018 2:52 pm
- Forum: Lewis Acids & Bases
- Topic: HI or HCl: stronger acid
- Replies: 8
- Views: 10451
Re: HI or HCl: stronger acid
HI has longer bond than HCl, making its bond weaker. Therefore it is easier for HI to lose H+, making it a stronger acid.
- Mon Dec 03, 2018 2:49 pm
- Forum: Biological Examples
- Topic: Biological Importance of Coordination Compounds
- Replies: 3
- Views: 356
Re: Biological Importance of Coordination Compounds
I think just knowing the ones he went over in lecture should be fine
- Mon Dec 03, 2018 2:46 pm
- Forum: Naming
- Topic: Roman Numeral
- Replies: 5
- Views: 576
Re: Roman Numeral
Is it possible to ever have a negative oxidation number? If so how would that be reflected in the name because there is no +/- sign in the brackets
- Sat Dec 01, 2018 5:52 pm
- Forum: Naming
- Topic: 9C.1 7th edition alphabetical order when naming
- Replies: 2
- Views: 334
9C.1 7th edition alphabetical order when naming
On the question 9C.1 part c) why is the answer aquapentacyanocobaltate and not pentacyanoaquacobaltate ? I thought we rank the ligands based on their name on the periodic table. Did I remember wrong and we actually rank the alphabetical order based on their actual name?
- Sat Dec 01, 2018 5:44 pm
- Forum: Naming
- Topic: 9C.1 7th Ed. Homework question naming
- Replies: 1
- Views: 227
Re: 9C.1 7th Ed. Homework question naming
-ate is added to the end of the metal name if the complex has an overall negative charge but not when the the complex has an overall positive charge or if the complex is neutral.
- Tue Nov 27, 2018 8:16 pm
- Forum: Dipole Moments
- Topic: LDF
- Replies: 5
- Views: 552
Re: LDF
Yes, it is "universal".
- Tue Nov 27, 2018 8:16 pm
- Forum: Electronegativity
- Topic: regions of e- density
- Replies: 4
- Views: 926
Re: regions of e- density
The sp^3 hybridization would occur when you have 4 regions of e- density
- Tue Nov 27, 2018 8:14 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework 9
- Replies: 3
- Views: 386
Re: Homework 9
The homework doesnt necessarily have to be from the immediate week. It can be from the older weeks as long as the content has already been covered in class.
- Mon Nov 26, 2018 1:26 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3
- Replies: 10
- Views: 1108
Re: Test 3
Test 3 covers: End of Bonding from 3.12 (6 Ed.) and from 2D (7 Ed.); and all of Molecular Shape and Structure (see Syllabus and Outlines for details) <-- from the class website
- Sun Nov 25, 2018 2:10 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing VSEPR
- Replies: 2
- Views: 354
Drawing VSEPR
Does it matter which way (horizontal or vertical) we draw the VSEPR model as long as theh indicate the same arrangement & shape? For example the one on the left shows that the O bonds are being pushed down because of the lone pair but in the solution manual the structure is as on the right.
- Sat Nov 24, 2018 10:51 pm
- Forum: Dipole Moments
- Topic: 7th edition 3F.15 polarity and boiling points
- Replies: 1
- Views: 330
7th edition 3F.15 polarity and boiling points
The book asks to explain why AsF3 has significantly higher boiling point than AsF5 and in the solution its because AsF3 is a polar molecule. What makes AsF3 polar? Is it because the lone pair pushes the 3 F bonds down and so the vectors don't cancel out whereas in AsF5 all 5 bonds are spread out aro...
- Tue Nov 20, 2018 1:13 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3 dates?
- Replies: 11
- Views: 1251
Re: Test 3 dates?
Initially on the syllabus test 3 was listed during week 8 but it has since changed. Test 3 will start on the 27th [after thanksgiving break].
- Tue Nov 20, 2018 1:12 am
- Forum: Administrative Questions and Class Announcements
- Topic: Grades
- Replies: 7
- Views: 836
Re: Grades
Approximately yes, the accurate number I believe will be calculated after taking into account the class' average
- Tue Nov 20, 2018 1:10 am
- Forum: Administrative Questions and Class Announcements
- Topic: Discussion
- Replies: 6
- Views: 692
Re: Discussion
We do have discussions but we dont have to hand in any homework this week
- Wed Nov 14, 2018 3:52 pm
- Forum: Properties of Electrons
- Topic: Polar vs Non polar
- Replies: 15
- Views: 4563
Re: Polar vs Non polar
It depends on the difference in electronegativity of the atoms. C-H for example have similar electronegativity and therefore is nonpolar because electrons are shared equally between the 2 atoms.
- Wed Nov 14, 2018 3:49 pm
- Forum: Resonance Structures
- Topic: Formal Charge
- Replies: 13
- Views: 1367
Re: Formal Charge
Negative charge should be on the more electronegative atom such as oxygen and positive charge should be on the less electronegative atom. However this comes seconds to filling up octets or getting the overall charge to 0.
- Wed Nov 14, 2018 3:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing shape based off of lewis structure
- Replies: 4
- Views: 468
Re: Drawing shape based off of lewis structure
I believe we don't need to be able to draw the wedge and shape model, and I dont think which atom goes to the front/back matters as long as their positions don't affect the angle/structure of the molecule.
- Wed Nov 14, 2018 3:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Remembering
- Replies: 8
- Views: 800
Re: Remembering
https://i.pinimg.com/originals/8c/76/d0/8c76d0df9e1d578b46a2d8fb02bf7f24.png here's a chart I've been using. you probably don't want to rely on it since we won't have it on the test but its been helpful for me to double check my answers with it before looking in the solutions manual Thank you so mu...
- Wed Nov 07, 2018 10:13 am
- Forum: Significant Figures
- Topic: Exam
- Replies: 6
- Views: 1151
Re: Exam
The "everything you need to know about SigFigs" section on Lavelle's website is really clear and helpful you should definitely check it out!
- Wed Nov 07, 2018 10:12 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3005850
Re: Post All Chemistry Jokes Here
Q: Why do chemists call helium, curium, and barium the medical elements?
A: Because if you can't helium or curium, you barium!
A: Because if you can't helium or curium, you barium!
- Wed Nov 07, 2018 10:09 am
- Forum: Trends in The Periodic Table
- Topic: Electronegativity vs. Electron Affinity?
- Replies: 11
- Views: 1618
Re: Electronegativity vs. Electron Affinity?
They are related because if an element has a tendency to take electron (high electron affinity), then it would take a lot of energy to remove one from that element, since the element likes/tends to gain an electron rather than lose an electron. This follows the trend that elements on the right on th...
- Mon Nov 05, 2018 12:44 am
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 17184
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Can someone explain 1. to me?
Thanks in advance!
Thanks in advance!
- Sun Nov 04, 2018 8:39 pm
- Forum: Photoelectric Effect
- Topic: Test 2 #4 neon lamp light emitted
- Replies: 1
- Views: 297
Test 2 #4 neon lamp light emitted
On test 2 #4 a) the question says at the threshold level light is emitted with energy equal to 3.61x10^-22 kJ. Find the frequency of the emitted photon.
How do I find the frequency of the emitted photon? Is it just the normal E=hV? --> E/h = V ?
How do I find the frequency of the emitted photon? Is it just the normal E=hV? --> E/h = V ?
- Sun Nov 04, 2018 8:11 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Monday review sessions
- Replies: 2
- Views: 271
Monday review sessions
Does anyone know if the 3 review sessions will cover the same practice problems? Because they are during normal lecture times that professor Lavelle teaches I think they might be the same but am not sure. If anyone could clarify that would be helpful!
- Sun Nov 04, 2018 12:21 am
- Forum: Administrative Questions and Class Announcements
- Topic: Happy Birthday, Dr. Lavelle!
- Replies: 3
- Views: 446
Re: Happy Birthday, Dr. Lavelle!
Happy Birthday prof!!
- Fri Nov 02, 2018 12:03 am
- Forum: Lewis Structures
- Topic: 2B. 9 7th edition chemical formula of sodium hypochloride
- Replies: 1
- Views: 220
2B. 9 7th edition chemical formula of sodium hypochloride
Are we suppose to be able to write the chemical formula for sodium hypochloride? Is there another way of figuring out it's ClO- without memorizing? Because in order to write the Lewis structure we need its chemical formula.
- Thu Nov 01, 2018 10:18 pm
- Forum: Lewis Structures
- Topic: 7th edition 2b9
- Replies: 3
- Views: 285
Re: 7th edition 2b9
I also want to know if we were expected to know the chemical formula when given a less obvious compound name like ammonium chloride?
- Mon Oct 29, 2018 10:28 am
- Forum: Trends in The Periodic Table
- Topic: Exceptions to electron configuration
- Replies: 3
- Views: 471
Re: Exceptions to electron configuration
Are the 2 exceptions the only ones we need to know? It seems there are more as you go down the periodic table.
- Mon Oct 29, 2018 10:24 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Balmer series, Lyman series?
- Replies: 3
- Views: 403
Re: Balmer series, Lyman series?
I think you only need to to know that both the Lyman and Balmer series are spectral line for H atoms and that Balmer series is the visible region in which the final n [n1] is 2. For Lyman series n1 is 1 and it lies in the ultraviolet region.
- Mon Oct 29, 2018 10:11 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 4s becomes higher energy
- Replies: 3
- Views: 2966
Re: 4s becomes higher energy
The 4s subshell is lower in energy than the 3d subshell, so it fills up first. The 4s becomes higher in energy after filling up, so if you ionize the atom, electrons are lost from the 4s subshell before the 3d subshell. But that's not how I learned it so it just confuses me to think of it that way....
- Mon Oct 29, 2018 1:02 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 4f, 5d, and 6s orbitals
- Replies: 2
- Views: 2810
4f, 5d, and 6s orbitals
I know 6s should be filled first before electrons can start filling 5d orbitals. The textbook states that after 6s is filled, 4f will start to be filled, and only after 4f is filled then electrons can start filling 5d? This is the case with the example of ytterbium [Xe]4f^14 6s^2. However, Cerium's ...
- Sun Oct 28, 2018 9:15 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3005850
Re: Post All Chemistry Jokes Here
saw this on facebook
- Thu Oct 25, 2018 2:20 am
- Forum: *Particle in a Box
- Topic: Particle in a box (textbook) [ENDORSED]
- Replies: 4
- Views: 1339
Re: Particle in a box (textbook) [ENDORSED]
Did he mention particle in a box in lecture briefly and I missed it or is it just in the textbook?
- Thu Oct 25, 2018 2:19 am
- Forum: Einstein Equation
- Topic: λ=h/p vs λ=hc/E
- Replies: 6
- Views: 3645
Re: λ=h/p vs λ=hc/E
It also depends on what values you are given/asked
- Thu Oct 25, 2018 2:18 am
- Forum: Administrative Questions and Class Announcements
- Topic: test 2
- Replies: 5
- Views: 678
Re: test 2
Materials that should only be in test 1 [i.e. not related to the quantum world section] will not be on but the test is still kind of cumulative in a way that you would need to apply some knowledge from test 1 to be able to fully do test 2.
- Thu Oct 25, 2018 2:16 am
- Forum: Trends in The Periodic Table
- Topic: Removing 2nd Electron
- Replies: 9
- Views: 726
Re: Removing 2nd Electron
The pull of the remaining electrons also becomes stronger after each electron removal because the pull is now divided/distributed among less electrons
- Sun Oct 21, 2018 4:16 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Hw 1D.9 - radial nodes and angular nodal surfaces differences
- Replies: 1
- Views: 219
Hw 1D.9 - radial nodes and angular nodal surfaces differences
In 1D.9 in the 7th edition part c of the question asks about the number of radial nodes and angular nodal surfaces. I recognize only nodal planes from the lecture. For this our purposes for this class what are the significant differences [if any] of radial nodes, angular nodal surfaces, and nodal pl...
- Mon Oct 15, 2018 10:35 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3005850
Re: Post All Chemistry Jokes Here
You're a 10? On the pH scale maybe, cuz you're basic.
- Mon Oct 15, 2018 10:30 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing reactions tips
- Replies: 29
- Views: 2044
Re: Balancing reactions tips
I find it helpful, especially when balancing equations with many different elements, to keep track of the amount of each element on the side. It might be a bit tedious if you have to update them each time you change the amount in the equation but usually it works well for me.
- Mon Oct 15, 2018 10:26 am
- Forum: Significant Figures
- Topic: 200. decimal sig figs
- Replies: 5
- Views: 5339
Re: 200. decimal sig figs
If your answer is 200 and need to write your answer in 3 sigfigs you can write 200, but if the lowest given value from the question has 4 sigfigs you would need to answer in 4 sigfigs as well. You would write 200.0 which has 4 sigfigs.
- Mon Oct 15, 2018 10:24 am
- Forum: DeBroglie Equation
- Topic: detectability of waves
- Replies: 4
- Views: 412
Re: detectability of waves
Judging from the homework and examples in class I believe we on tests would get answers that would be obvious. For example 10^-12 [picometer] would be detectable and 10^-24 would not.
- Tue Oct 09, 2018 12:17 am
- Forum: Administrative Questions and Class Announcements
- Topic: Homework due this Week [ENDORSED]
- Replies: 4
- Views: 456
Re: Homework due this Week [ENDORSED]
You can turn homework from the high school review section as well as the new topic as long as it has been covered. So if your discussion is on Thursday you would have a little bit more questions to choose for the homework.
- Tue Oct 09, 2018 12:15 am
- Forum: Administrative Questions and Class Announcements
- Topic: 'extra credit' in Sapling Learning
- Replies: 7
- Views: 1297
Re: 'extra credit' in Sapling Learning
I've thought about it and I don't think it is extra credit, since Prof Lavelle hasn't mentioned anything about it at all and it is not even on the syllabus.
- Tue Oct 09, 2018 12:14 am
- Forum: Significant Figures
- Topic: Rounding Using Significant Figures
- Replies: 10
- Views: 1439
Re: Rounding Using Significant Figures
I think one of the TAs mentioned the maximum point we could lose on sig fig related errors are 4 points. You're supposed to apply the sig fig rules at the very end of calculation, I usually keep a longer sig fig during calculations to avoid any errors.
- Tue Oct 02, 2018 1:31 pm
- Forum: Administrative Questions and Class Announcements
- Topic: 'extra credit' in Sapling Learning
- Replies: 7
- Views: 1297
Re: 'extra credit' in Sapling Learning
No it's on Sapling Learning where you can access your etextbook: http://www.saplinglearning.com/ibiscms/ ... p?id=87018
- Tue Oct 02, 2018 12:34 pm
- Forum: Administrative Questions and Class Announcements
- Topic: 'extra credit' in Sapling Learning
- Replies: 7
- Views: 1297
'extra credit' in Sapling Learning
I noticed the practice assignments or quizzes on Sapling Learning are labelled 'extra credits'. However on the syllabus there isn't a grade for it and the website itself says the practice assignments are optional. Does this mean they aren't really extra credits?
- Mon Oct 01, 2018 3:17 pm
- Forum: Limiting Reactant Calculations
- Topic: Percent yield
- Replies: 10
- Views: 940
Re: Percent yield
It should either be given or information should be given for you to find out on your own but you need both the actual and theoretical values to find the percent yield.
- Mon Oct 01, 2018 3:15 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question G21 [ENDORSED]
- Replies: 5
- Views: 416
Re: Question G21 [ENDORSED]
I also got 4.57x10^-2, but I think both answers should be fine
- Mon Oct 01, 2018 3:11 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3005850
Re: Post All Chemistry Jokes Here
How often do I tell chemistry jokes?
Periodically.
Periodically.