Search found 17913 matches

by Chem_Mod
Mon Dec 09, 2019 10:54 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 225
Views: 102299

Re: Saying Thank You to Dr. Lavelle

Great to read the positive feedback. Much appreciated.

Enjoy your break and I'll see you in Chem 14B.
by Chem_Mod
Mon Dec 09, 2019 12:20 am
Forum: Administrative Questions and Class Announcements
Topic: FINAL
Replies: 7
Views: 79

Re: FINAL

Several lectures on acids and bases. An entire lecture on salts and how they affect pH. Then a 2nd lecture on using salts to determine pH at the stoichiometric point. There were no other types of titration questions, no calculations. Only salts at the stoichiometric point. That is, [acid] = [base] =...
by Chem_Mod
Sun Dec 08, 2019 11:50 pm
Forum: Administrative Questions and Class Announcements
Topic: THE SONG DJ LL PLAYS AT THE BEGINNING OF CLASS [ENDORSED]
Replies: 7
Views: 529

Re: THE SONG DJ LL PLAYS AT THE BEGINNING OF CLASS [ENDORSED]

Never be numb, always reach out and share, even if its something small, its a start.

Enjoy your break.
by Chem_Mod
Sun Dec 08, 2019 7:55 pm
Forum: General Science Questions
Topic: Titration
Replies: 2
Views: 28

Re: Titration

See lecture notes. Same example.
by Chem_Mod
Sun Dec 08, 2019 7:54 pm
Forum: Student Social/Study Group
Topic: Final discussion
Replies: 4
Views: 46

Re: Final discussion

An entire lecture on salts and how they affect pH.
Then a 2nd lecture on using salts to determine pH at the stoichiometric point.

There were no other types of titration questions, no calculations. Only salts at the stoichiometric point.
by Chem_Mod
Sun Dec 08, 2019 7:49 pm
Forum: General Science Questions
Topic: Grades
Replies: 5
Views: 50

Re: Grades

Final grades will be posted on MyUCLA in about 10 days.
by Chem_Mod
Sun Dec 08, 2019 6:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Thank You!!
Replies: 1
Views: 23

Re: Thank You!!

Great post and thank you!
See you in class next quarter. :-)
by Chem_Mod
Sun Dec 08, 2019 5:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 225
Views: 102299

Re: Saying Thank You to Dr. Lavelle

Thank you for the positive feedback which encourages me to keep assisting students.
It was a great quarter!
by Chem_Mod
Sun Dec 08, 2019 5:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Grades [ENDORSED]
Replies: 2
Views: 82

Re: Final Grades [ENDORSED]

Grading on final exam is done very carefully and takes a lot of time.
In about 10 days after the final exam.
by Chem_Mod
Sun Dec 08, 2019 5:26 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelating ligands [ENDORSED]
Replies: 21
Views: 1352

Re: chelating ligands [ENDORSED]

A chelating ligand is a ligand that forms more than one bond to the same transition metal.
Results in a ring of atoms that includes the transition metal atom.

See lecture notes and textbook for multiple examples.
by Chem_Mod
Sun Dec 08, 2019 1:26 pm
Forum: Polyprotic Acids & Bases
Topic: 6C.21 [ENDORSED]
Replies: 1
Views: 17

Re: 6C.21 [ENDORSED]

Yes. I covered them in class.
by Chem_Mod
Sun Dec 08, 2019 1:25 pm
Forum: Bronsted Acids & Bases
Topic: 6A.9 [ENDORSED]
Replies: 1
Views: 23

Re: 6A.9 [ENDORSED]

This question has been omitted as it is an organic addition reaction.
by Chem_Mod
Sun Dec 08, 2019 1:21 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge [ENDORSED]
Replies: 1
Views: 7

Re: Formal Charge [ENDORSED]

Usually we ask for the most stable structures which are the optimal (low) formal charge.
by Chem_Mod
Sun Dec 08, 2019 1:19 pm
Forum: Air Pollution & Acid Rain
Topic: Blood pH [ENDORSED]
Replies: 1
Views: 14

Re: Blood pH [ENDORSED]

See pages 490 and 491 for acid rain.

See pages 506 and 507 for blood.
by Chem_Mod
Sun Dec 08, 2019 1:13 pm
Forum: Quantum Numbers and The H-Atom
Topic: Degenerate orbitals in H-atom [ENDORSED]
Replies: 1
Views: 15

Re: Degenerate orbitals in H-atom [ENDORSED]

Because there is no electron-electron shielding/interaction.
by Chem_Mod
Sun Dec 08, 2019 1:11 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Metallocene (sandwich) [ENDORSED]
Replies: 1
Views: 22

Re: Metallocene (sandwich) [ENDORSED]

Not part of the syllabus.
by Chem_Mod
Sun Dec 08, 2019 1:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: atomic spectrum [ENDORSED]
Replies: 1
Views: 33

Re: atomic spectrum [ENDORSED]

Use the measured wavelengths to identify the element(s) in a sample.
Maybe arsenic was used to poison someone …

Should I use this example in class?

:-)
by Chem_Mod
Sun Dec 08, 2019 10:51 am
Forum: Properties of Electrons
Topic: z effective
Replies: 1
Views: 22

Re: z effective

Don’t worry about this equation. Just know the atomic radius trends as you move from left to right in a row and down a column. When moving left to right in a row it’s the Z or number of protons that we care about. As you increase number of protons moving left to right in a row then atomic radius dec...
by Chem_Mod
Sun Dec 08, 2019 10:47 am
Forum: Properties of Light
Topic: photon vs wave
Replies: 1
Views: 22

Re: photon vs wave

Yes, make sure to keep the equations for light separate from the equations for particles. Light has the following two equations: c= wavelength* frequency and Energy=Hf. These equations can only be used for light. Similarly, for a particle you have the De Broglie wave equation wavelength=h/mv. This m...
by Chem_Mod
Sun Dec 08, 2019 10:45 am
Forum: Conjugate Acids & Bases
Topic: Finding Conjugate A and B
Replies: 4
Views: 12

Re: Finding Conjugate A and B

Correct.
by Chem_Mod
Sun Dec 08, 2019 10:44 am
Forum: Biological Examples
Topic: Heme complex
Replies: 5
Views: 35

Re: Heme complex

The Heme complex is an example of a biological coordination compound, which makes up hemoglobin and myoglobin. Both of these molecules use their heme complexes to bind and release O2 depending on environmental conditions, which is what oxygenates your organs and muscles.
by Chem_Mod
Sun Dec 08, 2019 10:42 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen bonding
Replies: 3
Views: 16

Re: Hydrogen bonding

No, only one of them have to have a H bound to it. However, the other one must be one of these electronegative atoms.
by Chem_Mod
Sun Dec 08, 2019 10:26 am
Forum: Amphoteric Compounds
Topic: examples
Replies: 2
Views: 20

Re: examples

Write as you would any other proton donating or accepting reaction. Write one reaction for it acting as an acid (donate proton to water) and one for it acting as a base (accept proton from water).
by Chem_Mod
Sun Dec 08, 2019 10:25 am
Forum: Amphoteric Compounds
Topic: amphiprotic vs amphoteric
Replies: 1
Views: 14

Re: amphiprotic vs amphoteric

Amphiprotic means molecule can both accept and donate a proton. This makes it necessarily amphoteric as well, which is a molecule that can act as both an acid and a base. Acids and bases by Lewis definition do not have to donate or accept protons
by Chem_Mod
Sun Dec 08, 2019 10:22 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelating ligands [ENDORSED]
Replies: 21
Views: 1352

Re: chelating ligands [ENDORSED]

You will not be asked to draw the entire structure of EDTA. However it may be helpful to know which atoms/lone pairs are involved in forming coordinate covalent bonds
by Chem_Mod
Sun Dec 08, 2019 10:21 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6c.17
Replies: 5
Views: 34

Re: 6c.17

Anions will not always be stronger bases than some neutral molecules, but you will not be expected to recognize which neutral molecules are stronger bases. Focus on recognizing strong bases (groip 1 and 2 metal cation hydroxides and oxides) as discussed in class. You do not need to be able to calcul...
by Chem_Mod
Sun Dec 08, 2019 10:18 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Kw
Replies: 3
Views: 25

Re: Kw

Yes, Kw calculations will be covered in 14B
by Chem_Mod
Sun Dec 08, 2019 10:17 am
Forum: Air Pollution & Acid Rain
Topic: examples
Replies: 1
Views: 15

Re: examples

Not sure which biological examples you are referring to
by Chem_Mod
Sun Dec 08, 2019 10:16 am
Forum: Identifying Acidic & Basic Salts
Topic: salt solutions
Replies: 6
Views: 21

Re: salt solutions

Know which ions from salts will react with water and thus whether the salt turns solution acidic or basic
by Chem_Mod
Sun Dec 08, 2019 10:16 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka only in weak acids and bases?
Replies: 2
Views: 12

Re: Ka only in weak acids and bases?

Ka for strong acids and bases is huge, assume 100% dissociation for these so no need to use Ka calculations
by Chem_Mod
Sun Dec 08, 2019 10:15 am
Forum: Biological Examples
Topic: Cis vs Trans
Replies: 3
Views: 19

Re: Cis vs Trans

Not necessary to know for this class but in an alkene, ie HCH3C=CCH3H, cis has the identical attachments on the carbons on the same side, trans has them on opposite sides
by Chem_Mod
Sun Dec 08, 2019 10:11 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: common acids and bases
Replies: 4
Views: 15

Re: common acids and bases

Strong acids: HCl, HBr, HI, H2SO4, HClO4, HNO3
Strong bases: Hydroxides and oxides of group 1 and 2 metal cations ie NaOH, CaO
by Chem_Mod
Sun Dec 08, 2019 10:09 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Carboxylic Acid
Replies: 2
Views: 23

Re: Carboxylic Acid

Carboxylic acid is COOH: Carbon is double bonded to an O and attached to a hydroxide group. oxyacids is simply A-O-H where the A is anything covalently bonded to OH. Carboxylic acids are organic (C containing) oxoacids
by Chem_Mod
Sun Dec 08, 2019 10:07 am
Forum: Identifying Acidic & Basic Salts
Topic: weak acids and bases
Replies: 2
Views: 22

Re: weak acids and bases

No they both do. If either [H+] or [OH-] changes then the pH is affected
by Chem_Mod
Sun Dec 08, 2019 10:06 am
Forum: Lewis Acids & Bases
Topic: all acids and bases
Replies: 4
Views: 21

Re: all acids and bases

Yes, you should be able to know the difference in definition between Lewis acid/base vs. Bronsted acid/base.
by Chem_Mod
Sun Dec 08, 2019 10:06 am
Forum: Hybridization
Topic: pi bonds
Replies: 3
Views: 22

Re: pi bonds

Pi bonds are side by side overlap of p orbitals
by Chem_Mod
Sun Dec 08, 2019 10:05 am
Forum: Sigma & Pi Bonds
Topic: Hybridization of Pi Bonds
Replies: 1
Views: 17

Re: Hybridization of Pi Bonds

For the pi bond in a C-C double bond: (C2p, C2p). This is the general format: start with the atom involved in the bond, then the orbital used. It will always be p orbital for pi bond but the 2 may change depending on what the outermost shell is.
by Chem_Mod
Sun Dec 08, 2019 10:04 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: boiling point of SiH4 vs SiCl4
Replies: 1
Views: 19

Re: boiling point of SiH4 vs SiCl4

You are correct; since the dipoles cancel out, they each have only London forces. SiCl4, Cl is larger and thus more electron dense than H, so London forces between SiCl4 molecules are stronger, making it take more energy to be boiled and become gaseous
by Chem_Mod
Sun Dec 08, 2019 10:02 am
Forum: Quantum Numbers and The H-Atom
Topic: msub l
Replies: 1
Views: 6

Re: msub l

Yes
by Chem_Mod
Sun Dec 08, 2019 10:00 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Compounds Structures
Replies: 1
Views: 24

Re: Coordination Compounds Structures

Number of bonds to central metal cation gives coordination number. If this number is 4, then complex is either square planar or tetrahedral, write both choices bc we cannot distinguish between the two in this course. If coordination is 6, it is octahedral. You do not need to worry about number of va...
by Chem_Mod
Sun Dec 08, 2019 9:58 am
Forum: Biological Examples
Topic: vitamin b-12
Replies: 2
Views: 33

Re: vitamin b-12

Vitamin B-12 is crucial to the normal function of the brain and the nervous system. It is also involved in the formation of red blood cells and helps to create and regulate DNA. It also plays a part in the synthesis of fatty acids and energy production in cell metabolism.
by Chem_Mod
Sun Dec 08, 2019 9:58 am
Forum: Lewis Acids & Bases
Topic: 6.13
Replies: 1
Views: 13

Re: 6.13

Please specify what your confusion is. Simply rewriting the entire problem will not count as a valid post
by Chem_Mod
Sun Dec 08, 2019 9:57 am
Forum: Identifying Acidic & Basic Salts
Topic: 6D11 part e
Replies: 1
Views: 15

Re: 6D11 part e

by Chem_Mod
Sun Dec 08, 2019 9:56 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6d.11f
Replies: 1
Views: 17

Re: 6d.11f

In class we discussed small metal cations not in group 1 and 2 (mainly transition metal cations) will act as acids in water. First they form coordinate covalent compounds with water molecules; these water molecules will then lose a proton to free floating water molecules, thus generating hydronium i...
by Chem_Mod
Sun Dec 08, 2019 9:53 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9
Replies: 1
Views: 9

Re: 6B.9

Solutions manual has a mistake; the pH is negative as you described
by Chem_Mod
Sun Dec 08, 2019 9:52 am
Forum: Lewis Acids & Bases
Topic: B(OH)3 problem 6.13
Replies: 2
Views: 18

Re: B(OH)3 problem 6.13

Hydroxides of Group 1 and 2 metal cations are strong bases; do not assume everything with a hydroxide group will be a strong base. B(OH)3 is a covalent compound so will not dissolve in water, thus OH- will not be released. Remember boron is an exception to the octet rule: having only 3 valence elect...
by Chem_Mod
Sun Dec 08, 2019 9:48 am
Forum: Trends in The Periodic Table
Topic: Mg2+ and F-
Replies: 1
Views: 18

Re: Mg2+ and F-

You’ve answered your question in your own post; Mg is lower in the periodic table and thus larger, using one more electron shell than fluorine. This is the case for the ions as well
by Chem_Mod
Sun Dec 08, 2019 9:37 am
Forum: Administrative Questions and Class Announcements
Topic: Chem Comm accesss
Replies: 1
Views: 17

Re: Chem Comm accesss

Access ends when the Chem 14A class ends and starts again first day of Chem 14B.
by Chem_Mod
Sun Dec 08, 2019 9:35 am
Forum: Biological Examples
Topic: Carbon monoxide poisoning
Replies: 2
Views: 28

Re: Carbon monoxide poisoning

Because the carbon atom has a negative charge.
by Chem_Mod
Sat Dec 07, 2019 10:50 pm
Forum: Quantum Numbers and The H-Atom
Topic: Midterm 6A
Replies: 1
Views: 39

Re: Midterm 6A

I believe this is a mistake and it should be all six electrons
by Chem_Mod
Sat Dec 07, 2019 9:03 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 3781

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

In Mini Marshmallows 1C, why does the NO3- in NH4NO3 not participate in the reaction with water, but NH4+ does? I just want to make sure I understand this conceptually before the final. Thank you! Answer: HNO 3 is a strong acid. Since its conjugate base is NO 3 - , that tells us that NO 3 - does no...
by Chem_Mod
Sat Dec 07, 2019 8:23 pm
Forum: General Science Questions
Topic: Final exam
Replies: 3
Views: 70

Re: Final exam

Relax and keep focused.

They are fine. More importantly his chemistry classes have the highest student success rate at UCLA.
by Chem_Mod
Sat Dec 07, 2019 8:04 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 3781

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

Ariana Iranmahboub 3G wrote:For number 22 why can myoglobin bind to two O2 molecules?
In my notes from the lecture, Fe binds to only 1 02 since the heme complex and a protein results in Myoglobin, so how would myoglobin bind to two O2?

It only binds 1 O2 molecule!
by Chem_Mod
Sat Dec 07, 2019 8:03 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 3781

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

Jedrick Zablan 3L wrote:Lyndon, I want to see the video you were trying to show during the review. Pls post it king.


It was baby groot dancing! Opening scene of guardians of the galaxy. Love it. I actually played it at the end once most people had left, it was quite fun. Next time maybe!
by Chem_Mod
Sat Dec 07, 2019 7:59 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 3781

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

Hi all, I was going through the final review packet and have been having trouble understanding part of problem 17. In the problem, it asks us to draw C5H5NO2 and label all of the sigma and pi bonds. I understand most of the question, but one of the pi bonds is troubling me. Near the top of the mole...
by Chem_Mod
Sat Dec 07, 2019 7:21 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong vs. Weak Acids
Replies: 3
Views: 22

Re: Strong vs. Weak Acids

Hi, HOI and HOCl are oxoacids. Look at stability of conjugate base ClO-. The conjugate base is more stable when the electron density is distributed over more atoms versus concentrated on the oxygen only. Cl is more electronegative than I, so it can withdraw more electron density from the Oxygen. Thi...
by Chem_Mod
Sat Dec 07, 2019 7:16 pm
Forum: Conjugate Acids & Bases
Topic: metal hydroxide reaction in water?
Replies: 1
Views: 17

Re: metal hydroxide reaction in water?

M+ + OH- + H2O --> M+ + H2O + OH-
or net ionic equation simply: OH- + H2O --> H2O + OH-
Yes it is the same on both sides
by Chem_Mod
Sat Dec 07, 2019 7:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sulfato
Replies: 1
Views: 22

Re: Sulfato

Yes and shape of the sulfate means it can only bind twice to the same cation
by Chem_Mod
Sat Dec 07, 2019 7:12 pm
Forum: Bronsted Acids & Bases
Topic: acetate functional group [ENDORSED]
Replies: 1
Views: 25

Re: acetate functional group [ENDORSED]

Not sure what you are asking.

Many biological molecules have the acetate group, COO-, which forms after the functional group, COOH, has released H+.
by Chem_Mod
Sat Dec 07, 2019 7:12 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Alkaline vs. acidic solutions
Replies: 2
Views: 10

Re: Alkaline vs. acidic solutions

acid should be protonated when pH is less than pKa, not the other way around. When pH is higher than pka, the acid HA will lose its proton to water, forming A- and H3O+ and the solution will be more acidic
by Chem_Mod
Sat Dec 07, 2019 7:10 pm
Forum: Octet Exceptions
Topic: Boron
Replies: 1
Views: 7

Re: Boron

Boron has only three valence electrons, so it can only form three bonds
by Chem_Mod
Sat Dec 07, 2019 7:05 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH less than 0?
Replies: 1
Views: 13

Re: pH less than 0?

The solutions manual has a mistake; you are correct that it would be negative
by Chem_Mod
Sat Dec 07, 2019 7:04 pm
Forum: Identifying Acidic & Basic Salts
Topic: Nonmetal oxides
Replies: 2
Views: 23

Re: Nonmetal oxides

because they are covalent compounds and not ionic compounds. Ionic compounds dissolve in water.
by Chem_Mod
Sat Dec 07, 2019 7:04 pm
Forum: Amphoteric Compounds
Topic: amphiprotic character
Replies: 1
Views: 13

Re: amphiprotic character

acidic: HCO3- + H2O --> CO3(2-) + H3O+
basic: HCO3- + H2O--> H2CO3 + OH-
by Chem_Mod
Sat Dec 07, 2019 7:02 pm
Forum: Bond Lengths & Energies
Topic: single bonds and s bonds [ENDORSED]
Replies: 1
Views: 41

Re: single bonds and s bonds [ENDORSED]

In general: Sigma bonds are usually stronger than pi bonds. Double bond stronger than single. Triple bond stronger than double. I discussed this trend in class using the organic examples: CH 3 CH 3 CH 2 CH 2 CHCH There is no trend in hybridization type and bond strength. For example: H-F is a strong...
by Chem_Mod
Sat Dec 07, 2019 7:01 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids
Replies: 3
Views: 23

Re: Lewis Acids

Boron and other atoms in its group can act as Lewis acids because they cannot obtain a full octet by themselves, having only 3 valence electrons. Positively charged atoms can also act as Lewis acids since accepting a lone pair will neutralize the positive charge.
by Chem_Mod
Sat Dec 07, 2019 6:55 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Kw
Replies: 3
Views: 25

Re: Kw

Kw was not discussed in 14A so you do not need to know it. It is the equilibrium constant for the autoionization of water into [OH-] and [H3O+]
by Chem_Mod
Sat Dec 07, 2019 6:55 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 9
Replies: 1
Views: 12

Re: 6B. 9

No, there is a mistake in the solutions manual. The pH should be negative as it is for solutions with [H3O+] > 1.0 M
by Chem_Mod
Sat Dec 07, 2019 6:54 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted
Replies: 1
Views: 15

Re: Lewis vs Bronsted

All Bronsted acids/bases are also Lewis acids/bases. An example of Lewis acid that is not a Bronsted acid is BF3. Boron in BF3 does not yet have a full octet so can accept a lone pair from another atom such as F-. However there is no exchange of protons involved, so it is not a Bronsted acid/base re...
by Chem_Mod
Sat Dec 07, 2019 6:54 pm
Forum: Hybridization
Topic: s orbital [ENDORSED]
Replies: 1
Views: 30

Re: s orbital [ENDORSED]

In general: Sigma bonds are usually stronger than pi bonds. Double bond stronger than single. Triple bond stronger than double. I discussed this trend in class using the organic examples: CH 3 CH 3 CH 2 CH 2 CHCH There is no trend in hybridization type and bond strength. For example: H-F is a strong...
by Chem_Mod
Sat Dec 07, 2019 6:53 pm
Forum: Administrative Questions and Class Announcements
Topic: TAs for next quarter, Chem 14B
Replies: 1
Views: 28

Re: TAs for next quarter, Chem 14B

If you want your TA for Chem 14B ask them.
by Chem_Mod
Sat Dec 07, 2019 6:52 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: homework question 6C.17
Replies: 1
Views: 13

Re: homework question 6C.17

hypobromite is negatively charged while morphine is not. Hypobromite would thus become neutral upon addition of a proton while morphine would become positively charged, which is less favorable. Thus hypobromite is the stronger base
by Chem_Mod
Sat Dec 07, 2019 6:50 pm
Forum: Biological Examples
Topic: structures and formula for biological compounds
Replies: 1
Views: 33

Re: structures and formula for biological compounds

No, these structures will be provided
by Chem_Mod
Sat Dec 07, 2019 6:49 pm
Forum: Lewis Acids & Bases
Topic: reactions
Replies: 2
Views: 8

Re: reactions

If you are asking about acid/base reactions, yes they are dissolved in water (aqueous solution denoted by "aq") unless otherwise specified
by Chem_Mod
Sat Dec 07, 2019 6:48 pm
Forum: Identifying Acidic & Basic Salts
Topic: 6.21 (C)
Replies: 1
Views: 16

Re: 6.21 (C)

the lone pair on N can accept a proton (gaining a formal charge of +1), and the H on the N can also be donated, giving the N a formal charge of -1. Please include the complete question in future posts
by Chem_Mod
Sat Dec 07, 2019 6:46 pm
Forum: Quantum Numbers and The H-Atom
Topic: Identical Values for Quantum Numbers
Replies: 1
Views: 13

Re: Identical Values for Quantum Numbers

n refers to the electron shell (principle quantum number). l represents the orbital (0=s, 1=p, 2=d, etc). First figure out what these numbers are for the unpaired electrons on Bromine. Then figure out how many electrons are in those same orbitals. This would be the 4p orbitals for Bromine
by Chem_Mod
Sat Dec 07, 2019 6:41 pm
Forum: Identifying Acidic & Basic Salts
Topic: 6.21 part (c)
Replies: 1
Views: 12

Re: 6.21 part (c)

The nitrogens have a lone pair that can accept protons. They can also lose their proton and gain a formal charge of negative one. You can write the equilibria equations the same way you would for any acid-base reactions
by Chem_Mod
Sat Dec 07, 2019 6:34 pm
Forum: Bronsted Acids & Bases
Topic: FJ.7
Replies: 1
Views: 7

Re: FJ.7

PO4(3-) will react with water to form HPO4 (2-) and OH-
by Chem_Mod
Sat Dec 07, 2019 6:32 pm
Forum: Identifying Acidic & Basic Salts
Topic: 6.21 c
Replies: 1
Views: 15

Re: 6.21 c

Donating the H attached to N will result in another lone pair on the N and a formal charge of negative 1
by Chem_Mod
Sat Dec 07, 2019 6:30 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculations for KA
Replies: 1
Views: 10

Re: Calculations for KA

Ka is the equilibrium constant for deprotonation of acids. The higher Ka is, the stronger the acid and thus the more protons lost and lower the pH. Ka for strong acids is huge, so about 100% dissociation occurs. Ka is more of a 14B topic so you will not need to use it in pH calculations
by Chem_Mod
Sat Dec 07, 2019 6:27 pm
Forum: Polyprotic Acids & Bases
Topic: Calculating pH of polyprotic acid
Replies: 2
Views: 25

Re: Calculating pH of polyprotic acid

Yes for the first dissociaton. The second dissassociation is like that of a weak acid, which is not covered in 14A so will not be included in the exam
by Chem_Mod
Sat Dec 07, 2019 6:27 pm
Forum: Conjugate Acids & Bases
Topic: cations
Replies: 2
Views: 11

Re: cations

Can you provide an example of what you are referring to?
by Chem_Mod
Sat Dec 07, 2019 6:25 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: relative strength of weak acids
Replies: 1
Views: 17

Re: relative strength of weak acids

Use bond length for acids of the motif H-A, like HCl and HBr. Look at the stability of the conjugate base for oxoacids of the form A-O-H like HClO2. For bond length: stronger acids lose protons more easily, and this is more easily done if the bond between H and A is weaker. Longer bonds are weaker. ...
by Chem_Mod
Sat Dec 07, 2019 6:17 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: stability of conj. base oxo acids and electronegativity
Replies: 1
Views: 13

Re: stability of conj. base oxo acids and electronegativity

You are correct that the greater the stability of the conjugate base, the stronger the acid. However, think of it more as electronegative atoms attached to the negatively charged O of the conjugate base that result in a more stable structure. These electronegative atoms are able to withdraw more ele...
by Chem_Mod
Sat Dec 07, 2019 6:11 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Thymine
Replies: 1
Views: 19

Re: Thymine

It has lone pairs on the nitrogen and oxygen that can accept protons
by Chem_Mod
Sat Dec 07, 2019 6:09 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6c.17
Replies: 5
Views: 34

Re: 6c.17

Hypobromite ion is negatively charged while morphine is neutral. HBrO is neutral while morphine would become positively charged after accepting a proton, which is less favorable. Thus hypobromite is the the stronger base
by Chem_Mod
Sat Dec 07, 2019 6:02 pm
Forum: Naming
Topic: Ligands
Replies: 6
Views: 42

Re: Ligands

Yup
by Chem_Mod
Sat Dec 07, 2019 4:54 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: HW 6D.11 part e
Replies: 1
Views: 27

Re: HW 6D.11 part e

Look over your notes concerning small metal cations acting as acids. These include many transition metal cations like Al3+. They will first form coordinate covalent compounds with water. These water molecules then lose their proton to free-floating water molecules, forming hydronium. The water on th...
by Chem_Mod
Sat Dec 07, 2019 4:52 pm
Forum: *Stereochemistry
Topic: Various Isomers
Replies: 1
Views: 17

Re: Various Isomers

You do not need to know this for 14A. This is more 14C and D material
by Chem_Mod
Sat Dec 07, 2019 4:50 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination number and shape
Replies: 1
Views: 34

Re: coordination number and shape

Coordination number is found by counting the total number of bonds made to the central metal cation. En is bidentate and there are 2 of them, so that's 4 bonds, plus 2 cyanides means 2 more bonds for a total of 6 bonds and a coordination number of 6. In the second compound, each hydroxide binds once...
by Chem_Mod
Sat Dec 07, 2019 4:45 pm
Forum: Naming
Topic: Coordrination Number (Polydentate ligands)
Replies: 2
Views: 33

Re: Coordrination Number (Polydentate ligands)

Know everything on the chart under "naming coordination compounds" posted on the class website
by Chem_Mod
Sat Dec 07, 2019 4:44 pm
Forum: Properties of Electrons
Topic: Wave-particle duality
Replies: 1
Views: 15

Re: Wave-particle duality

Yes; electrons are commonly thought of as particles and that is how they interact with photons, but they also have diffraction patterns. Their wavelengths can also be found using De Broglie's equation
by Chem_Mod
Sat Dec 07, 2019 4:43 pm
Forum: Student Social/Study Group
Topic: electrons on a lewis structure
Replies: 2
Views: 22

Re: electrons on a lewis structure

Yes unless you have a radical
by Chem_Mod
Sat Dec 07, 2019 4:42 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Anion Stability & Acid Strength
Replies: 1
Views: 21

Re: Anion Stability & Acid Strength

Across a period, anion stability increases because anions have electrons filling up to the same energy level/shell, but increasing electronegativity and number of protons as you move to the right. This helps with handling the negative charge. Down a group, stability of anion increases because as the...
by Chem_Mod
Sat Dec 07, 2019 4:39 pm
Forum: Hybridization
Topic: Charges
Replies: 4
Views: 24

Re: Charges

If formal charge on an atom is not 0, please include the charge on the atom
by Chem_Mod
Sat Dec 07, 2019 4:38 pm
Forum: Conjugate Acids & Bases
Topic: Neutralization Equations
Replies: 3
Views: 24

Re: Neutralization Equations

Neutralization reactions between acids and bases form a salt (ionic compound) and water. The salt is often written as something like NaCl (aq), but recognize that this actually means Na+ and Cl- dissolved in water. Not all chemical reactions will result in neutral products
by Chem_Mod
Sat Dec 07, 2019 4:36 pm
Forum: Bronsted Acids & Bases
Topic: Main Difference
Replies: 1
Views: 12

Re: Main Difference

By definition, Lewis acids are species that can accept a lone pair of electrons. Bronsted-Lowry acids are species that can donate protons. A Bronsted-Lowry acid is always a Lewis acid, but a Lewis acid is not always a Bronsted-Lowry acid because the exchange in Lewis acids does not always include a ...
by Chem_Mod
Sat Dec 07, 2019 4:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: Midterm Question 6A
Replies: 1
Views: 12

Re: Midterm Question 6A

The solutions to the midterm can be found on the class website

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