When will final grades be posted/available on MyUCLA?
Good Luck with the rest of Finals!
Search found 101 matches
- Sun Dec 09, 2018 5:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Grade View
- Replies: 7
- Views: 905
- Sat Dec 08, 2018 5:47 pm
- Forum: Conjugate Acids & Bases
- Topic: Conjugates of Weak Acids/Bases
- Replies: 1
- Views: 496
Conjugates of Weak Acids/Bases
I understand that Strong Acids have Weak Conjugate Bases and that Strong Bases have Weak Conjugate Acids... Does this mean that Weak Acids have Strong Conjugate Acids? Why or Why not? Can someone please thoroughly explain this to me. I am having a difficult time with weak acid and weak base reactions.
- Sat Dec 08, 2018 5:46 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 2
- Views: 564
Re: Acid Strength
Why does H have a greater electron withdrawing ability?
- Sat Dec 08, 2018 5:36 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 2
- Views: 564
Acid Strength
Why is Structure 2 a stronger acid than Structure 4?
- Thu Dec 06, 2018 4:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Naming on the Final
- Replies: 4
- Views: 517
Re: Naming on the Final
Di you think naming will be emphasized much on the final as we just learned it in the last few days? Dr. Lavelle said that the Final will cover everything in the Syllabus as it is meant to and I think he implied that each section will be equally represented. So, yes. It will be emphasized as it is ...
- Thu Dec 06, 2018 12:49 am
- Forum: Conjugate Acids & Bases
- Topic: Thymine Question
- Replies: 1
- Views: 659
Thymine Question
The homework asks, "12.127... The two strands of the nucleic acid DNA are held together by hydrogen bonding between four organic bases. The structure of one of these bases, thymine, is shown below. (a) How many protons can this base accept? (b) Draw the structure of each conjugate acid that can...
- Wed Dec 05, 2018 11:57 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis bases and Coordinate Covalence
- Replies: 1
- Views: 263
Lewis bases and Coordinate Covalence
Can someone confirm that the only bonds that Lewis bases make are coordinate covalent bonds?
- Wed Dec 05, 2018 11:00 pm
- Forum: Naming
- Topic: Parentheses in Naming
- Replies: 1
- Views: 339
Parentheses in Naming
In the compound name,
sodium bisoxalato(diaqua)ferrate(III)
is there a significance to the parentheses around "diaqua" ? what is the purpose ? Does this change the writing of the compound somehow?
sodium bisoxalato(diaqua)ferrate(III)
is there a significance to the parentheses around "diaqua" ? what is the purpose ? Does this change the writing of the compound somehow?
- Wed Dec 05, 2018 8:45 pm
- Forum: Naming
- Topic: [Co(P(CH3)3)4]2(SO4)3
- Replies: 1
- Views: 4189
[Co(P(CH3)3)4]2(SO4)3
What would the naming for this coordination compound be?
[Co(P(CH3)3)4]2(SO4)3
[Co(P(CH3)3)4]2(SO4)3
- Wed Dec 05, 2018 7:01 pm
- Forum: Naming
- Topic: so4 2- ligand name
- Replies: 1
- Views: 2327
so4 2- ligand name
On Dr. Lavelle's worksheet it is provided that SO4 2- written as OSO3 2- is "sulfato". What is it called when the ligand is bonded to the Sulfur atom? (Or, alternatively, is the sulfate ligand always attached to the Metal through Oxygen?)
- Wed Dec 05, 2018 6:54 pm
- Forum: Naming
- Topic: iso-ligands
- Replies: 1
- Views: 251
iso-ligands
How are we supposed to know when to put the original ligand (i.e. CN- cyano ) vs. the iso-ligand (i.e. NC- isocyano) ?
Will the bonding atom always be underlined (on the final) in these cases?
Will the bonding atom always be underlined (on the final) in these cases?
- Wed Dec 05, 2018 6:51 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Memorize All Ligands?
- Replies: 1
- Views: 251
Memorize All Ligands?
There are some ligands on Dr. Lavelle's worksheet, such as isothiocyanato, that we have not really seen in class or on the homework. Are we still expected to know/memorize them for the final?
- Tue Dec 04, 2018 8:29 pm
- Forum: Trends in The Periodic Table
- Topic: Group 5 Transition Metals
- Replies: 2
- Views: 411
Group 5 Transition Metals
When a question is referring to "Group 5 transition metals" is it referring to the column with Vanadium or Manganese?
- Mon Dec 03, 2018 11:30 pm
- Forum: Lewis Structures
- Topic: Acid Base Lewis Structures
- Replies: 2
- Views: 415
Re: Acid Base Lewis Structures
Well, yes, but a double bond between Oxygen and Chlorine would also make the formal charge on Oxygen = 0.
Therefore, how do I know where to attach the Hydrogen if both Lewis Structures have a net charge of 0?
Therefore, how do I know where to attach the Hydrogen if both Lewis Structures have a net charge of 0?
- Mon Dec 03, 2018 11:27 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: KBr has Neutral pH ?
- Replies: 1
- Views: 1206
KBr has Neutral pH ?
Why does KBr have a neutral pH but KF has a pH greater than 7?
(This question is referring to Homework Problem 12.65 (c) and (d) )
(This question is referring to Homework Problem 12.65 (c) and (d) )
- Mon Dec 03, 2018 11:22 pm
- Forum: Conjugate Acids & Bases
- Topic: Writing Ion Formulas
- Replies: 1
- Views: 299
Writing Ion Formulas
In problem 12.65 part (c),
When writing the aqueous solution of KF, how do we know to write the formula
F- + H2O --> HF + -OH
instead of making the solution about the K+ ion?
When writing the aqueous solution of KF, how do we know to write the formula
F- + H2O --> HF + -OH
instead of making the solution about the K+ ion?
- Mon Dec 03, 2018 11:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Naming on the Final
- Replies: 4
- Views: 517
Naming on the Final
Questions on the homework expected us to know the formula for acids such as Formic Acid... are we supposed to know names of acids like these by memorization for the final, or will the chemical formula be provided for acids? (esp. those such as Formic Acid that are not obvious)
- Mon Dec 03, 2018 11:01 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Electronegativity vs. Size in Acid Strength
- Replies: 1
- Views: 981
Electronegativity vs. Size in Acid Strength
In 12.51,
HClO2 is a stronger acid than HBrO2 and same goes for H2CO3 > H2GeO3 on the claim that Cl and C are more electronegative than Br and Ge.
How does electronegativity affect the strength of an acid? Shouldn't HBrO2 and H2GeO3 be stronger acids because Br and Ge are larger?
HClO2 is a stronger acid than HBrO2 and same goes for H2CO3 > H2GeO3 on the claim that Cl and C are more electronegative than Br and Ge.
How does electronegativity affect the strength of an acid? Shouldn't HBrO2 and H2GeO3 be stronger acids because Br and Ge are larger?
- Mon Dec 03, 2018 10:57 pm
- Forum: Lewis Structures
- Topic: Acid Base Lewis Structures
- Replies: 2
- Views: 415
Acid Base Lewis Structures
When do we know when to attach the H atom to Oxygen atom(s) instead of the central atom?
For example, as in HClO2
For example, as in HClO2
- Mon Dec 03, 2018 10:30 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Calculating Kb or Given?
- Replies: 1
- Views: 250
Re: Calculating Kb or Given?
Furthermore, can you calculate pKb with only this information (from the problem) provided?
- Mon Dec 03, 2018 10:29 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Calculating Kb or Given?
- Replies: 1
- Views: 250
Calculating Kb or Given?
For problem 12.49 (provided in the image below). The solutions manual compares the pK b for the two molecules in order to compare the strength of their basic character. Are we supposed to be able to calculate these values, or are they given somewhere? Is there a way to compare the strength of their ...
- Mon Dec 03, 2018 10:16 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH and Molarity
- Replies: 2
- Views: 295
pH and Molarity
Can someone walk me through Homework Problem 12.27?
I understand that the desired pH is just -log (given M) = 1.6
However I don't understand part (b). Can someone please walk me through it?
I understand that the desired pH is just -log (given M) = 1.6
However I don't understand part (b). Can someone please walk me through it?
- Mon Dec 03, 2018 9:05 pm
- Forum: Amphoteric Compounds
- Topic: Textbook Error?
- Replies: 1
- Views: 265
Textbook Error?
The 6th edition textbook claims that Bi2O3 is an amphoteric compound, yet Dr. Lavelle's slides from Friday's lecture claim that Bi2O3 is acidic. Which is correct?
Furthermore, in cases such as this, is there a way to identify amphoteric compounds other than simply memorizing them?
Furthermore, in cases such as this, is there a way to identify amphoteric compounds other than simply memorizing them?
- Mon Dec 03, 2018 8:57 pm
- Forum: Lewis Acids & Bases
- Topic: Identifying Lewis acid
- Replies: 2
- Views: 312
Identifying Lewis acid
In the reaction,
Cl- + SO2 --> SO2Cl
Both Cl- and the S in SO2 have lone pairs. Why is Cl- the Lewis acid and not SO2?
Cl- + SO2 --> SO2Cl
Both Cl- and the S in SO2 have lone pairs. Why is Cl- the Lewis acid and not SO2?
- Mon Dec 03, 2018 8:51 pm
- Forum: Lewis Acids & Bases
- Topic: Lone Pairs only on Central Atoms?
- Replies: 2
- Views: 321
Lone Pairs only on Central Atoms?
Lone pairs on outer atoms (bonded atoms) don't make the molecule a Lewis base, correct?
For example, BF3 is a Lewis acid because Boron doesn't have any Lone Pairs.... the lone pairs on the bonded F atoms don't change that?
For example, BF3 is a Lewis acid because Boron doesn't have any Lone Pairs.... the lone pairs on the bonded F atoms don't change that?
- Mon Dec 03, 2018 8:41 pm
- Forum: Bronsted Acids & Bases
- Topic: No Proton Transfer?
- Replies: 2
- Views: 297
Re: No Proton Transfer?
I know that this was brought up on another post on Chemistry Community, but no one explained why there is no proton transfer.
- Mon Dec 03, 2018 8:37 pm
- Forum: Bronsted Acids & Bases
- Topic: No Proton Transfer?
- Replies: 2
- Views: 297
No Proton Transfer?
Homework 12.9 says that the formula
CH3COOH + NH3 --> CH3CONH2 + H2o
does not have Bronsted acids and bases because there is no proton transfer.
can someone explain how this is so ?
CH3COOH + NH3 --> CH3CONH2 + H2o
does not have Bronsted acids and bases because there is no proton transfer.
can someone explain how this is so ?
- Mon Dec 03, 2018 8:31 pm
- Forum: Bronsted Acids & Bases
- Topic: Acid Base Identification
- Replies: 1
- Views: 372
Acid Base Identification
Homework problem 12. 9 state that in the formula
NH4I --> NH3 + HI
NH4+ is the Bronsted acid and that I- is the Bronsted base. How is this possible, that the acid and base is the same compound?
Can someone please explain/walk me through this problem?
NH4I --> NH3 + HI
NH4+ is the Bronsted acid and that I- is the Bronsted base. How is this possible, that the acid and base is the same compound?
Can someone please explain/walk me through this problem?
- Mon Dec 03, 2018 8:27 pm
- Forum: Conjugate Acids & Bases
- Topic: Conjugate Acids and Bases in this formula
- Replies: 1
- Views: 235
Conjugate Acids and Bases in this formula
What are the conjugate acids and bases in this formula?
NH4 + H2O --> NH3 + H3O+ + I-
NH4 + H2O --> NH3 + H3O+ + I-
- Mon Dec 03, 2018 8:22 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands and Lewis bases
- Replies: 3
- Views: 505
Ligands and Lewis bases
Are the terms "Lewis base" and "Ligand" synonymous and interchangeable?
- Mon Dec 03, 2018 8:21 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acids and Bases
- Replies: 2
- Views: 498
Bronsted Acids and Bases
Does the classification of Bronsted Acids and Bases go beyond the idea that acids are proton donors and bases are proton acceptors?
Are the Lewis and Bronsted definitions of Acids and Bases direct opposites of each other? (i.e. Lewis acids accept protons but Bronsted acids donate protons)
Are the Lewis and Bronsted definitions of Acids and Bases direct opposites of each other? (i.e. Lewis acids accept protons but Bronsted acids donate protons)
- Mon Dec 03, 2018 8:11 pm
- Forum: Conjugate Acids & Bases
- Topic: Conjugate Base Notation
- Replies: 1
- Views: 217
Conjugate Base Notation
Regarding the final exam...
Would I lose points for writing the conjugate base of HCOOH as COOH- instead of HCO2- ?
Would I lose points for writing the conjugate base of HCOOH as COOH- instead of HCO2- ?
- Wed Nov 28, 2018 7:53 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentates
- Replies: 3
- Views: 507
Re: Polydentates
Additionally, for oxalate, why is it only a bidentate and not a tetra dentate?
In addition to one oxygen from each side being bonded, can't the oxygen adjacent to it also be bonded, as demonstrated by Dr. Lavelle's example in class (the chemotherapy example with Cl) ?
In addition to one oxygen from each side being bonded, can't the oxygen adjacent to it also be bonded, as demonstrated by Dr. Lavelle's example in class (the chemotherapy example with Cl) ?
- Wed Nov 28, 2018 7:36 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentates
- Replies: 3
- Views: 507
Polydentates
*Referring to question 17.33 (b) *
If the CO32- structure has 3 oxygen atoms, all equipped with at least one lone pair of electrons, then why can the ion only serve as a mono- or bidentate and not a tridentate ligand?
If the CO32- structure has 3 oxygen atoms, all equipped with at least one lone pair of electrons, then why can the ion only serve as a mono- or bidentate and not a tridentate ligand?
- Wed Nov 28, 2018 7:23 pm
- Forum: Naming
- Topic: Cyano vs. Cyanido
- Replies: 2
- Views: 780
Cyano vs. Cyanido
When (CN) is a ligand, when are we supposed to use "cyano" vs. "cyanido" in our naming? I have seen both and am not sure how to distinguish between when to use either one.
- Tue Nov 27, 2018 8:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 38397
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Why does LiCl exhibit greater ionic character than LiBr?
- Tue Nov 27, 2018 7:30 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3
- Replies: 2
- Views: 377
Test 3
Will we be asked questions about hybridization for molecules below the second period?
- Tue Nov 27, 2018 7:15 pm
- Forum: Hybridization
- Topic: Lone Pairs
- Replies: 1
- Views: 237
Lone Pairs
In 4.95 of 6th edition, the molecule drawn and labeled hybridization shows that the lone pairs on Oxygen are "sp2" . Why is it sp2 and not 2 sp2?
- Tue Nov 27, 2018 7:14 pm
- Forum: Hybridization
- Topic: Empty p orbitals
- Replies: 3
- Views: 1843
Re: Empty p orbitals
To clarify, I think I am trying to understand "unhybridized 2p orbitals" ?
- Tue Nov 27, 2018 7:12 pm
- Forum: Hybridization
- Topic: Empty p orbitals
- Replies: 3
- Views: 1843
Empty p orbitals
Can someone please explain through the concept of having "empty p orbitals" or something to do with lone pairs? Im referring to when the bond is ( C 2p, C 2p) I know Dr. Lavelle explained it in class but I don't actually understand what is occurring during this process of hybridization.
- Tue Nov 27, 2018 6:42 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Shape Bond Angles
- Replies: 8
- Views: 718
Re: Seesaw Shape Bond Angles
<90 and <120 or <90 and 120?
- Tue Nov 27, 2018 6:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Shape Bond Angles
- Replies: 8
- Views: 718
Seesaw Shape Bond Angles
What are the bond angles on a Seesaw shape?
- Tue Nov 27, 2018 2:46 pm
- Forum: Bond Lengths & Energies
- Topic: SO2 and SO3 bond length
- Replies: 2
- Views: 10396
SO2 and SO3 bond length
When comparing the bond lengths of SO2 and SO3.. Both structures are made up entirely of double bonds... however, SO2 has lone pairs on the Sulfur and SO3 does not, so would it be correct to assume that SO2 had slightly longer bonds than SO3? (I am assuming that the bonds in SO2 would be longer beca...
- Tue Nov 27, 2018 2:15 pm
- Forum: Ionic & Covalent Bonds
- Topic: Can an organic compound have an ionic bond?
- Replies: 1
- Views: 312
Can an organic compound have an ionic bond?
Can an organic compound have an ionic bond?
- Tue Nov 27, 2018 2:04 pm
- Forum: Dipole Moments
- Topic: Size and IM interactions
- Replies: 2
- Views: 136
Size and IM interactions
Dr. Lavelle's slides read, "INCREASING SIZE OR MOLAR MASS RESULTS IN STRONGER ATTRACTIVE INTERACTIONS" can someone please explain why this is true and provide an example?
- Tue Nov 27, 2018 1:59 pm
- Forum: Bond Lengths & Energies
- Topic: Intermolecular Potential Energy
- Replies: 3
- Views: 447
Intermolecular Potential Energy
In the formula for intermolecular potential energy, E , what does r stand for? Does it describe the distance between the two molecules, or the radius of one of the molecules? This is important because I am trying to understand the parameters that contribute to IM energy and I am trying to derive the...
- Tue Nov 27, 2018 1:45 pm
- Forum: Dipole Moments
- Topic: Examples of Intermolecular forces
- Replies: 2
- Views: 449
Examples of Intermolecular forces
Can someone please provide examples of intermolecular forces (other than hydrogen bonding) in organic and biological molecules?
If possible, could you provide an example per type of intermolecular force (ion-ion, dipole-dipole, London...etc.)
If possible, could you provide an example per type of intermolecular force (ion-ion, dipole-dipole, London...etc.)
- Tue Nov 27, 2018 1:37 pm
- Forum: Dipole Moments
- Topic: Hydrogen Bonding Strength
- Replies: 2
- Views: 342
Hydrogen Bonding Strength
Why is hydrogen bonding so strong? What is unique about the force that attributes to its strength?
- Tue Nov 27, 2018 1:31 pm
- Forum: Bond Lengths & Energies
- Topic: Study Guide
- Replies: 1
- Views: 159
Study Guide
The study guide reads, "Know the relative magnitudes of intermolecular forces and hydrogen bonds." What is this describing? What is the extent of knowledge that this study guide point is demanding (i.e. how much are we expected to know in detail?) Is this just asking that we can rank the i...
- Tue Nov 27, 2018 1:28 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ion-Ion and Ionic Bonds
- Replies: 1
- Views: 325
Ion-Ion and Ionic Bonds
Is describing the intermolecular force of ion-ion the same as describing molecules that share an ionic bond?
- Mon Nov 26, 2018 11:48 pm
- Forum: Bond Lengths & Energies
- Topic: Study Guide
- Replies: 1
- Views: 211
Study Guide
The study guide reads, "Explain how covalent bond dissociation energy is related to covalent bond multiplicity, atomic radius, and the presence of unpaired electrons." First, what is covalent bond multiplicity? Second, can someone please provide the explanation for this? (i.e. answer this ...
- Sun Nov 25, 2018 9:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2 Lone Pairs, Placement
- Replies: 3
- Views: 658
Re: 2 Lone Pairs, Placement
Therefore... it is safe to assume that when the electron density shape is Tetrahedral, the 2 lone pairs will always be next to each other? Thus, in CH2 2- , which has a tetrahedral, I would place the 2 LP next to each other.
- Sun Nov 25, 2018 8:49 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.109
- Replies: 2
- Views: 138
HW 4.109
In the problem, for (b) the answer says the bond angle is "around 109.5"
Because the Oxygen has two single bonds, don't we assume that the Oxygen has 2 Lone pairs on it, and therefore the bond angle becomes < 109.5 ?
Because the Oxygen has two single bonds, don't we assume that the Oxygen has 2 Lone pairs on it, and therefore the bond angle becomes < 109.5 ?
- Sun Nov 25, 2018 8:39 pm
- Forum: Hybridization
- Topic: Hybridization and Reactivity
- Replies: 2
- Views: 606
Hybridization and Reactivity
Homework Problem 4.91 asks us to evaluate why Benzyne would be highly reactive based off what we know about its hybridization in its structure. What is the relationship between hybridization and reactivity? Can someone walk me through the process of using knowing about Hybridization to predict react...
- Sun Nov 25, 2018 8:21 pm
- Forum: Lewis Structures
- Topic: Borazine Lewis Structure
- Replies: 1
- Views: 564
Borazine Lewis Structure
The lewis structure of Borazine has Boron atoms with double bonds connected to Nitrogen atoms in a hexagonal structure. How is it possible that the Boron atoms have a double bond?
- Sun Nov 25, 2018 8:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2 Lone Pairs, Placement
- Replies: 3
- Views: 658
2 Lone Pairs, Placement
When you have 2 lone pairs, how do you know if you should place them next to each other (as with H2O) or if they should be opposite each other (as with XeF4)? I'm asking because the question of CH2 2- came up, and the structure isn't clear because I don't know where the 2 lone pairs should be placed...
- Sun Nov 25, 2018 5:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent/Angular Shape
- Replies: 4
- Views: 514
Bent/Angular Shape
Can I assume that "angular" shape is the same as saying "bent" shape?
- Sun Nov 25, 2018 5:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.19
- Replies: 1
- Views: 171
HW 4.19
For the 6th edition textbook Homework Problem 4.19 (b) why do we write the bond angles (tetrahedral shape) around the Carbon atoms in addition to the shape around the central atom? Should we always do this when writing shapes of organic molecules?
- Sat Nov 24, 2018 5:34 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent Shape Angle
- Replies: 1
- Views: 330
Bent Shape Angle
Why does the Bent shape have bond angles less than 120 degrees rather than less than 180 degrees?
- Sat Nov 24, 2018 5:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lewis Structure N2O
- Replies: 4
- Views: 423
Lewis Structure N2O
Why is Nitrogen the central atom in N2O?
- Tue Nov 13, 2018 10:35 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: Lewis Structures before Forces?
- Replies: 2
- Views: 279
Lewis Structures before Forces?
How have you guys been approaching the Homework Problems on Intermolecular forces? Should we always draw out the lewis structure and/or geometric shape of molecules before determining the possible/expected intermolecular forces? (otherwise, how will we predict the unique cases where the dipoles canc...
- Tue Nov 13, 2018 10:33 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: Lewis Structures before Forces
- Replies: 3
- Views: 268
Lewis Structures before Forces
If a question provides a molecule and then asks about the expected or potential intermolecular forces of the molecule, should we draw the lewis structure and/or geometric structure? I know that some molecules have a geometric shape that cancels out the dipoles, which changes the type of intermolecul...
- Tue Nov 13, 2018 10:27 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: Homework 6.1 c
- Replies: 1
- Views: 335
Homework 6.1 c
This problem comes from Homework 6.1 (c) on the 6th edition textbook.
For the molecule H2SeO4 , why can Hydrogen Bonding exist as an intermolecular force? Shouldn't the forces only be London or Dipole-Dipole?
For the molecule H2SeO4 , why can Hydrogen Bonding exist as an intermolecular force? Shouldn't the forces only be London or Dipole-Dipole?
- Tue Nov 13, 2018 3:18 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: Shape and Boiling Point
- Replies: 12
- Views: 3013
Re: Shape and Boiling Point
Stronger interactions imply that the bond is harder to break. Boiling points refer to the minimal temperature required to break the bonds of the substance. Therefore, stronger interactions cause the substance to have a higher boiling point, and vice versa.
- Tue Nov 13, 2018 3:16 pm
- Forum: Electronegativity
- Topic: Polarity
- Replies: 3
- Views: 270
Re: Polarity
It doesn't hurt. You can demonstrate this through an arrow that points the direction the electrons are being pulled. On exams and homework problems, the instructions will likely specify when you should demonstrate polarity.
- Tue Nov 13, 2018 3:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Biological Activity
- Replies: 3
- Views: 354
Re: Biological Activity
As an example, think of enzymes. Substrate-Enzyme relationships depend on active sites shape. The shape of an active site depends on electron density. Without the right match of a substrate, enzymes cannot function.
- Sun Nov 04, 2018 4:54 pm
- Forum: Lewis Structures
- Topic: Lewis Structure(s)
- Replies: 3
- Views: 221
Lewis Structure(s)
On the exam, what if the question asks for the lewis structure of a structure that has resonance, but one of the structure has lower energy than the other 2 resonance structures? For example, SO 2 Technically, there are three resonance structures for SO 2 However, one of the three structures (the st...
- Sun Nov 04, 2018 4:34 pm
- Forum: Lewis Structures
- Topic: OCl2 Structure
- Replies: 1
- Views: 1002
OCl2 Structure
Can someone confirm what the lewis structure of OCl2 is?
Is Chlorine the central atom (because it is less electronegative than oxygen)?
Can Chlorine form double bonds?
Is Chlorine the central atom (because it is less electronegative than oxygen)?
Can Chlorine form double bonds?
- Sun Nov 04, 2018 12:54 pm
- Forum: Electronegativity
- Topic: Oxygen and Chlorine [ENDORSED]
- Replies: 2
- Views: 4587
Oxygen and Chlorine [ENDORSED]
Why is Oxygen more electronegative than Chlorine? (they are both adjacent to Fluorine so how would we be able to distinguish between them when looking at a periodic table)?
- Thu Nov 01, 2018 9:57 pm
- Forum: Lewis Structures
- Topic: Glycine Lewis Structure
- Replies: 1
- Views: 274
Glycine Lewis Structure
Homework Problem 3.41 in the 6th Edition textbook:
Lewis Structure of Glycine H2C(NH2)COOH ?
Can someone please walk me through the process of creating this complex lewis structure in an efficient and/or strategic manner?
Lewis Structure of Glycine H2C(NH2)COOH ?
Can someone please walk me through the process of creating this complex lewis structure in an efficient and/or strategic manner?
- Wed Oct 31, 2018 6:32 pm
- Forum: Trends in The Periodic Table
- Topic: Homework 2.59
- Replies: 3
- Views: 279
Re: Homework 2.59
The presence of exponents signifies that the atoms provided are not in their ground state but rather in ionic form. If we reflect on what Dr. Lavelle said in his lecture on Wednesday, ionic radius should increase as we go down a group. This is because each additional shell shields some electrons fr...
- Wed Oct 31, 2018 11:38 am
- Forum: Bond Lengths & Energies
- Topic: Bond Strength and Resonance
- Replies: 2
- Views: 366
Bond Strength and Resonance
Why are bonds strengthened by resonance?
- Tue Oct 30, 2018 10:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Electron Configuration
- Replies: 1
- Views: 246
Midterm Electron Configuration
Will we be asked for electron configurations involving the f-orbials (Row 6 and below) on the Midterm on Monday?
- Tue Oct 23, 2018 7:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 38397
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Many people have asked about #7 on Worksheet 2 and no one has responded.
Can someone please help us out and explain? The key is not clear... How did she get 1/n^2 = 0.0278 ???
Can someone please help us out and explain? The key is not clear... How did she get 1/n^2 = 0.0278 ???
- Tue Oct 23, 2018 3:00 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Study Guide Concept Question [ENDORSED]
- Replies: 1
- Views: 291
Study Guide Concept Question [ENDORSED]
A bullet point on the Study Guide reads, "With respect to electron transitions that give rise to a UV or visible spectrum: understand the difference between electronic transitions in atomic orbitals (atomic spectroscopy) and electronic transitions in molecular orbitals (molecular spectroscopy)....
- Tue Oct 23, 2018 2:48 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Test 2 Free Response [ENDORSED]
- Replies: 1
- Views: 295
Test 2 Free Response [ENDORSED]
I notice that in the textbook, when in solving equations, some solved equations are left with the constants written as their symbols and not as their numerical value. For example, see the photo I attached. Is this allowed for Test 2? Would we get full credit for an answer if we left the constants wr...
- Tue Oct 23, 2018 2:44 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Question 1.15 sixth edition
- Replies: 10
- Views: 765
Re: Question 1.15 sixth edition
Which equation do we use to figure this out?
- Tue Oct 23, 2018 2:43 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation / Negatives on Test 2
- Replies: 1
- Views: 188
Rydberg Equation / Negatives on Test 2
I am struggling to understand what the values of n1 and n2 are. Should n1 always be the smallest of the two numbers, or should n1 be the final position of the electron where n2 is the initial position of the electron? Additionally, if the electron were transitioning from (let's say) n=4 to n=2, then...
- Sun Oct 21, 2018 4:33 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals and periodic table
- Replies: 1
- Views: 283
Re: Orbitals and periodic table
It's important to remember that the periodic table was designed after the properties of elements were discovered and is deliberately organized in that fashion. I found this video that explains period trends (like the ones you're describing): https://www.youtube.com/watch?v=XK-WTYncldA
- Sun Oct 21, 2018 4:28 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: What is the equation used for?
- Replies: 9
- Views: 845
Re: What is the equation used for?
It measures the uncertainty of the position or momentum of electrons
- Tue Oct 16, 2018 10:31 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Question 1.15 sixth edition
- Replies: 10
- Views: 765
Re: Question 1.15 sixth edition
Also, the solution to this problem says that the transition is from n = 1 to n = 3, but the problem says that energy was emitted during this process. Isn't energy only emitted when an electron transitions from a higher energy to a lower energy? So... if it transitioned from n =1 to n=3, it should ha...
- Tue Oct 16, 2018 10:26 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Question 1.15 sixth edition
- Replies: 10
- Views: 765
Re: Question 1.15 sixth edition
Nicolette_Canlian_3G wrote:why is the energy level of 102.6 nm 1?
This is what i don't understand. Even when I see pictures of the spectroscopy with the Lyman series, I notice that 102.6 is one of the values next to a line, but I'm not sure how to identify that it is n=1 .
- Tue Oct 16, 2018 10:10 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: 1.11 Problem
- Replies: 3
- Views: 197
1.11 Problem
Hello, can someone thoroughly explain the answer to this homework problem {attached} ?
- Fri Oct 12, 2018 6:19 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Post-Mod Assessment #40
- Replies: 4
- Views: 276
Re: Post-Mod Assessment #40
This is all I know about the answer
- Fri Oct 12, 2018 5:12 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Deriving Formula for Wavelength
- Replies: 2
- Views: 360
Re: Deriving Formula for Wavelength
Jovian Cheung 1K wrote:
Does it start like this? (I'm curious too) :o)
Yes, it started like that!
- Fri Oct 12, 2018 4:45 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Post-Mod Assessment #40
- Replies: 4
- Views: 276
Post-Mod Assessment #40
I cannot seem to get this question right for the life of me: "What is the wavelength of radiation emitted by a hydrogen atom in a transition from the n=6 to the n=5 energy level?" If you are able to help, could you actually write out all your numerical calculations (not just provide the th...
- Fri Oct 12, 2018 4:35 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Deriving Formula for Wavelength
- Replies: 2
- Views: 360
Deriving Formula for Wavelength
In trying to solve the problem, "What is the wavelength emitted by a hydrogen atom in its transition from n=6 to n=5 energy level?" I tried to derive a formula from the formula E= ch/wavelength and E = -hR / n^2 I got the formula (wavelength) = -c (n^2) / R which I then used (Delta E) = Ef...
- Tue Oct 09, 2018 7:15 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Rounding on Exams
- Replies: 1
- Views: 209
Rounding on Exams
While completing a practice test I noticed sometimes my answers were off by .001 and I am worried this will affect my scores on the exam. How accurate do we need to be on the test before we get points deducted? For example, if my answer was 3.21 x 10^27 and the answer key says it is 3.22 x 10^27 , w...
- Tue Oct 09, 2018 6:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 1 Study Plan
- Replies: 6
- Views: 571
Re: Test 1 Study Plan
Is test 2 solely going to be Quantum World material, or will it be cumulative? I'm trying not to fall behind in Chapter 1, but I also want to continue studying the review topics This is a good question if one of the TAs/UAs/Professor has an actual answer. Consider this for now though: Chemistry is ...
- Tue Oct 09, 2018 5:57 pm
- Forum: Photoelectric Effect
- Topic: Vacuum
- Replies: 4
- Views: 303
Re: Vacuum
What are the consequences of the electrons reacting with molecules in the air?
- Tue Oct 09, 2018 3:11 pm
- Forum: Photoelectric Effect
- Topic: Vacuum
- Replies: 4
- Views: 303
Vacuum
Without having to go too in depth, can someone explain the reason for the idea of a"vacuum" and why this experiment has to take place under the conditions of one? I also noticed that a vacuum environment is a condition for the definition of the speed of light. Just looking for some backgro...
- Tue Oct 09, 2018 3:08 pm
- Forum: Limiting Reactant Calculations
- Topic: 6th Edition, Problem M.11
- Replies: 1
- Views: 1174
Re: 6th Edition, Problem M.11
This is one of the challenge problems of the homework for sure. After you finish part A, you know that O2 is the limiting reactant. Whenever we discover the limiting reactant, we use the mass value of that compound available and do some dimensional analysis to figure out how much product is produced...
- Tue Oct 09, 2018 3:03 pm
- Forum: Balancing Chemical Reactions
- Topic: Element Names & Symbols
- Replies: 2
- Views: 381
Re: Element Names & Symbols
I spoke to my TA, and really they are only looking for you to know the fundamental compounds. For example, Water (H20), Carbon Dioxide (C02), and the diatomic gases (H2, F2, etc.) Remember that a periodic table should be given for the exam!
- Sat Oct 06, 2018 1:01 pm
- Forum: SI Units, Unit Conversions
- Topic: Formula Units?
- Replies: 6
- Views: 665
Formula Units?
A problem in the book asked, "How many formula units of the compound are present in 5.15 g of Magnesium Sulfate Heptahydrate?"
What are "formula units"?
What are "formula units"?
- Sat Oct 06, 2018 10:58 am
- Forum: SI Units, Unit Conversions
- Topic: Fundamental E3
- Replies: 6
- Views: 561
Fundamental E3
Please help I don't understand this problem! See attached IMG
- Sat Oct 06, 2018 10:05 am
- Forum: General Science Questions
- Topic: Orbitals
- Replies: 2
- Views: 391
Re: Orbitals
When you lose electrons, they always come from the highest energy level first because they are furthest away from the nucleus. We know that 4s orbitals have a lower energy than the 3d so therefore 4s electrons are actually lost first in ionization before 3d.
- Sat Oct 06, 2018 9:51 am
- Forum: Molarity, Solutions, Dilutions
- Topic: post assessment
- Replies: 1
- Views: 147
Re: post assessment
5.00 g of KMnO4 is dissolved in a 150.00 mL flask of water. If 20.00 mL of this solution is removed and placed in a new 2nd 250.00 mL flask and filled with water, what is the concentration of the solution in the 2nd flask? Molar Masses: K (39.10 g/mol), Mn (54.94 g/mol), O (16.00 g/mol) Why do you u...
- Wed Oct 03, 2018 12:38 am
- Forum: Limiting Reactant Calculations
- Topic: Two Limiting Reactants
- Replies: 6
- Views: 388
Two Limiting Reactants
I am stuck on the module post-assessment regarding whether two limiting reactants is possible. I would not think that two limiting reactants is possible unless the amounts of the two molecules perfectly completed the other. But then, no limiting reactant would exist. The options for why two limiting...
- Tue Oct 02, 2018 10:17 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Avogadro's Number
- Replies: 2
- Views: 287
Re: Avogadro's Number
It is universally applied through the definition of Avogadro's number, which is 6.02 x 10^23 particles. Scientists created the concept of the mole and defined it for their own purposes to convenience their calculations (so we just accept it for its definition and apply it as needed.) I have pondered...
- Tue Oct 02, 2018 10:11 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Registering/Creating Your Chemistry Community Account
- Replies: 40
- Views: 100233
Re: Registering/Creating Your Chemistry Community Account
Can you clarify if its 2 points max. per week or 3 points max. ?
Thank you!
Thank you!