Search found 16472 matches

by Chem_Mod
Thu Dec 06, 2018 9:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9 7th Edition
Replies: 1
Views: 51

Re: 6B.9 7th Edition

Well, -log(1)=0 and -log(10)=-1, so anything between 1-10 for [H+] should be negative. The manual probably is missing a negative.
by Chem_Mod
Thu Dec 06, 2018 9:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 7th edition 6B.9
Replies: 2
Views: 38

Re: 7th edition 6B.9

Well, -log(1)=0 and -log(10)=-1, so anything between 1-10 for [H+] should be negative. The manual probably is missing a negative.
by Chem_Mod
Thu Dec 06, 2018 9:35 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6D.11
Replies: 1
Views: 56

Re: 6D.11

When copper(II) nitrate dissociates in water, it forms Cu2+ and NO3-. Cu2+ is acidic since it is a transition metal, and NO3- is neutral because its the base of a strong acid, so it's relatively weak and doesn't do anything (spectator ion).
by Chem_Mod
Thu Dec 06, 2018 9:29 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pKa and Ka
Replies: 3
Views: 60

Re: pKa and Ka

The acid dissociation constant, Ka, is a quantitative indicator of the strength of an acid in a solution. Because Ka is often an extremely large number, chemists simplify it to a smaller number, called pKa, for convenience. Ka and pKa are the same thing expressed in different ways. Ka follows the ba...
by Chem_Mod
Thu Dec 06, 2018 9:29 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 7th edition 6C.19
Replies: 2
Views: 45

Re: 7th edition 6C.19

There's an idea called the inductive effect that explains this. Essentially, because chlorine is more electronegative than bromine, the negative charge on the oxygen after deprotonation is more easily delocalized throughout HClO2 versus HBrO2. This means HClO2's conjugate base is more stable than HB...
by Chem_Mod
Thu Dec 06, 2018 9:27 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate ligands
Replies: 1
Views: 42

Re: polydentate ligands

Any of these are fair game: https://lavelle.chem.ucla.edu/wp-conten ... pounds.pdf. Yes, those are correct dentate notations.
by Chem_Mod
Thu Dec 06, 2018 9:25 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 7th ed. 6C17
Replies: 1
Views: 29

Re: 7th ed. 6C17

Yes, you would use the pKa values to determine, which would be provided to you if asked.
by Chem_Mod
Thu Dec 06, 2018 9:22 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Nonmetal oxides
Replies: 1
Views: 35

Re: Nonmetal oxides

Well, technically bases are associated with the production of OH-, while acids are associated with the production of H+. This means that metal oxides (containing elements that tend to be positively charged) would be associated with making OH- (NaOH consists of Na+ and OH-), while nonmetal oxides (co...
by Chem_Mod
Thu Dec 06, 2018 9:18 pm
Forum: Amphoteric Compounds
Topic: Amphiteric compounds
Replies: 1
Views: 33

Re: Amphiteric compounds

Know the examples of amphoteric compounds and what it means to be amphoteric.
by Chem_Mod
Thu Dec 06, 2018 9:18 pm
Forum: Naming
Topic: edta charge and formula?
Replies: 1
Views: 36

Re: edta charge and formula?

EDTA has a -4 charge, as all the oxygens with acidic hydrogens are deprotonated. For the formula, it should be C10H12N2O8, since four hydrogens are gone from the original molecule.
by Chem_Mod
Thu Dec 06, 2018 9:12 pm
Forum: Naming
Topic: 7th ed. 9C9
Replies: 1
Views: 22

Re: 7th ed. 9C9

It depends on the complex each transition metal is in. Perhaps providing an example that you had trouble with would help. En refers to ethylenediammine, and EDTA refers to ethylenediaminetetraacetic acid.
by Chem_Mod
Thu Dec 06, 2018 9:09 pm
Forum: Lewis Acids & Bases
Topic: Identify the Salt Produced
Replies: 1
Views: 45

Re: Identify the Salt Produced

It should be (NH4)3PO3. Perhaps that's why you didn't get the correct quantity.
by Chem_Mod
Thu Dec 06, 2018 9:06 pm
Forum: Naming
Topic: 9C1 7th edition
Replies: 2
Views: 47

Re: 9C1 7th edition

Hi, I posted some notes here at this link: https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=157&t=38247&p=129743&hilit=coordination+compound&sid=05ea6f12f71e75b6ecc59a05bf7b6d6e#p129743. Essentially, if the overall complex has a positive charge, metal is same name as element (ex. ...
by Chem_Mod
Thu Dec 06, 2018 9:03 pm
Forum: Identifying Acidic & Basic Salts
Topic: HW 12.17
Replies: 2
Views: 60

Re: HW 12.17

Metal oxides tend to be basic. Nonmetal oxides tend to be acidic. Metalloid oxides tend to be amphoteric. You can check this by seeing how they react with water, and look at the resulting product.
by Chem_Mod
Thu Dec 06, 2018 9:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: CO3^2-
Replies: 2
Views: 46

Re: CO3^2-

It can be monodentate because it can use one lone pair form an oxygen to coordinate covalently bond to a metal cation. It can also be bidentate because it can use another lone pair from another oxygen to coordinate covalently bond to a metal cation in addition to the original oxygen. This is because...
by Chem_Mod
Thu Dec 06, 2018 4:24 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Kw
Replies: 2
Views: 23

Re: Kw

It's not so much that pH cannot be higher than 14. It's because of the math and operations. Since p means take -log, we can perform that operation on the value of Kw, which is 1x10^-14. That will give a value of 14. As [H+][OH-] = 1x10^-14, pH + pOH = 14. Remember that taking the log/exponent will t...
by Chem_Mod
Thu Dec 06, 2018 3:51 pm
Forum: General Science Questions
Topic: Chemistry Community [ENDORSED]
Replies: 7
Views: 108

Re: Chemistry Community [ENDORSED]

Chemistry Community is open to the end of Week 10.
Closes Monday the day after the final.
by Chem_Mod
Thu Dec 06, 2018 3:47 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Will we need to know how to use Ksubw the autoprotilysis constant for the final? [ENDORSED]
Replies: 1
Views: 25

Re: Will we need to know how to use Ksubw the autoprotilysis constant for the final? [ENDORSED]

"Will we need to know how to use Kw the autoprotilysis constant for the final?"
No

Yes: pH calculations for strong acids and bases as I did in class and in the HW.
by Chem_Mod
Thu Dec 06, 2018 2:29 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH of solutions
Replies: 1
Views: 26

Re: pH of solutions

You look at the molarity of [H+], not the molarity of the acid. Think about if you have a polyprotic acid where the acid dissociates into more than 1 H+, then you would have to multiply the acid's molarity by the number of H+ dissociated.

You can use the molarity of the base to find pOH.
by Chem_Mod
Thu Dec 06, 2018 2:27 pm
Forum: Conjugate Acids & Bases
Topic: Will any kind soul please let me know what we went over in class yesterday? (Wednesday)
Replies: 1
Views: 25

Re: Will any kind soul please let me know what we went over in class yesterday? (Wednesday)

We discussed salts as acids and bases as well as polyprotic acids. I would recommend getting notes from a fellow student.
by Chem_Mod
Thu Dec 06, 2018 2:26 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: in preparation for the exam...
Replies: 1
Views: 49

Re: in preparation for the exam...

Memorize common strong acids and bases.

As for identifying it it's an acid or base, draw the lewis structure and ask yourself: is this molecule stable if I add electrons? If I donate electrons?

As always, practice using the textbook problems and understand why something is an acid or base.
by Chem_Mod
Thu Dec 06, 2018 2:14 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 3601

Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

how might one solve question 34? Should the overall concentration be found or is it only necessary to find the concentration of HCL is 1 Liter of water? I will go over this in detail on Friday (tomorrow) -Lyndon As a hint, remember that you only look at Hydronium ions and hydroxide ions when determ...
by Chem_Mod
Thu Dec 06, 2018 1:59 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Equilibrium constants
Replies: 1
Views: 26

Re: Equilibrium constants

Equilibrium constants show us if products or reactants are favored in a reaction. If Keq >>>1, then the products are favored more than the reactants. On the other hand, if Keq <<<1, the products are favored less than the reactants. In terms of acids, a weak acid has a much lower Keq than a strong ac...
by Chem_Mod
Thu Dec 06, 2018 1:55 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka equation
Replies: 2
Views: 35

Re: Ka equation

Liquids and solids are left out of the Ka equation because their concentrations are "fixed." For a reaction taking place in water, the water "concentration" isn't affected because there's so many more water molecules than the reaction molecules.
by Chem_Mod
Thu Dec 06, 2018 1:51 pm
Forum: Naming
Topic: Cyanide (cyano vs isocyano)
Replies: 2
Views: 46

Re: Cyanide (cyano vs isocyano)

Cyano and isocyano differ in what the atom connectivity is. If C is the bonded atom, it can donate its lone pair to form a bond with the transition metal. Similarly, if N is the bonded atom, it can also donate its lone pair to form a bond. Here is a picture of how they may differ in terms of connect...
by Chem_Mod
Thu Dec 06, 2018 1:47 pm
Forum: Naming
Topic: naming
Replies: 2
Views: 38

Re: naming

If the complex has an overall negative charge, then you add the suffix "ate." If there's no overall negative charge, use just the metal name.
by Chem_Mod
Thu Dec 06, 2018 1:46 pm
Forum: Lewis Acids & Bases
Topic: Metal oxides
Replies: 1
Views: 21

Re: Metal oxides

Metal oxides are basic. Alkali metals in group 1 and alkaline earth metals in group 2 are examples of metal oxides, such as Li2O, CaO, and Mg(OH)2. Refer to this week's notes on Strong Bases.
by Chem_Mod
Thu Dec 06, 2018 1:42 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: HW: 6B.1 (7th)
Replies: 1
Views: 35

Re: HW: 6B.1 (7th)

The initial concentration of HCl (or H+) is [H+].
The final concentration of HCl is 12% of that, which is .12[H+].
Then use pH final - pH initial to find the change in pH.
Hint: Use log rules to combine the two terms into one term. H+ concentration will cancel out.
by Chem_Mod
Thu Dec 06, 2018 1:37 pm
Forum: Naming
Topic: iso-ligands
Replies: 1
Views: 36

Re: iso-ligands

If there's any discrepancy, it will be underlined. Refer to the table of common ligands (Table 17.4).
by Chem_Mod
Thu Dec 06, 2018 1:36 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable
Replies: 4
Views: 67

Re: Polarizable

Bigger anions are more polarizable because their electron cloud is larger and thus more easily distorted. Atomic size increases as you go down a column. Conversely, smaller cations have stronger polarizing power because their electrons are more "condensed" and can thus distort other electr...
by Chem_Mod
Thu Dec 06, 2018 1:33 pm
Forum: Hybridization
Topic: Composition
Replies: 1
Views: 19

Re: Composition

You can use either if the question doesn't specify to look at a particular sigma/pi bond. The coefficient is the principal quantum number (ie the row #) that the element is located in.
by Chem_Mod
Thu Dec 06, 2018 1:32 pm
Forum: Naming
Topic: Naming Coordination Complexes: Ion
Replies: 1
Views: 19

Re: Naming Coordination Complexes: Ion

A good rule of thumb is to add "ion" at the end if there is an overall charge on the complex. The "ate" implies that it's an ion, but adding on ion makes it more clear.
by Chem_Mod
Thu Dec 06, 2018 1:28 pm
Forum: Lewis Acids & Bases
Topic: 12.25 6th Edition Initial Molarity
Replies: 1
Views: 14

Re: 12.25 6th Edition Initial Molarity

For pOH, you want to find the concentration of [OH-].
For every mole of Ba(OH)2, you have 2 moles of OH-. Therefore, the concentration of OH- is double that of the initial molarity of Ba(OH)2.
by Chem_Mod
Thu Dec 06, 2018 1:26 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 5
Replies: 1
Views: 28

Re: 6B. 5

You must first find the concentration of OH. For every 1 mole of Ba(OH)2, we have 2 moles of OH. Therefore the concentration of OH is double that of Ba(OH)2.

You can find the pOH by taking -log[OH-].
The pH and pOH must add up to 14, so you can deduce the pH from that.
by Chem_Mod
Thu Dec 06, 2018 1:25 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C.21 (7th ed)
Replies: 1
Views: 31

Re: 6C.21 (7th ed)

Formic acid and acetic acid differs in that acetic acid has a CH3 group. CH3 is actually slightly electron releasing, meaning it pushes the electrons towards the OH bond. This makes the OH bond slightly stronger because of the increased electron density, so it's less likely to break and release the ...
by Chem_Mod
Thu Dec 06, 2018 10:23 am
Forum: Conjugate Acids & Bases
Topic: Finding Conjugate Acid for Thymine (problem 6.21 7th editiion)
Replies: 1
Views: 15

Re: Finding Conjugate Acid for Thymine (problem 6.21 7th editiion)

The oxygen is much more electronegative than nitrogen, so it's unlikely to share its electrons. If oxygen did share the electrons, it would gain a + charge, which is unstable. Nitrogen is much more favored to accept the H by donating its lone pair electrons.
by Chem_Mod
Thu Dec 06, 2018 10:22 am
Forum: Conjugate Acids & Bases
Topic: Thymine Question
Replies: 1
Views: 33

Re: Thymine Question

Oxygen is unlikely to share its electrons here because it's much more electronegative than Nitrogen. If oxygen shared its electrons, it would have a + charge on it, which is not very stable. That's why nitrogen is more favored in terms of accepting a hydrogen.
by Chem_Mod
Thu Dec 06, 2018 10:18 am
Forum: Naming
Topic: Naming Aqua
Replies: 1
Views: 17

Re: Naming Aqua

Either is fine. We sometimes use OH2 to indicate/clarify that the bond of the water ligand is being formed with the Oxygen, not Hydrogen.
by Chem_Mod
Thu Dec 06, 2018 10:17 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: (6th Edition) #12.19
Replies: 1
Views: 20

Re: (6th Edition) #12.19

In the solution manual, they use that equation to indicate the change in [H+]. If you started out with 1M H+ but diluted it to 12% concentration, then you would end up with .12M H+. The change in pH is thus the -log(new conc/old conc), which is -log(.12). You could also calculate the pH of the solut...
by Chem_Mod
Thu Dec 06, 2018 10:13 am
Forum: Dipole Moments
Topic: Dipole moment trends
Replies: 2
Views: 24

Re: Dipole moment trends

If a molecule has a net dipole moment, then the molecule is polar. It has partial positive and negative charges that strengthen the interactions with the partial negative on Oxygen (from H2O) and partial positive on Hydrogen (from H2O). It would make it more dissolvable in water if the molecule is p...
by Chem_Mod
Thu Dec 06, 2018 10:11 am
Forum: Amphoteric Compounds
Topic: homework question 12.11
Replies: 1
Views: 23

Re: homework question 12.11

Yes, your interpretation is correct.
by Chem_Mod
Thu Dec 06, 2018 10:08 am
Forum: Lewis Acids & Bases
Topic: BaO a Lewis acid ?
Replies: 3
Views: 49

Re: BaO a Lewis acid ?

BaO is basic because it's a metal oxide.
And yes, if you see an available lone pair on an atom, it generally acts as a Lewis base because it can donate those electrons.
by Chem_Mod
Thu Dec 06, 2018 10:01 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Base Trends
Replies: 1
Views: 31

Re: Base Trends

Use bond length when comparing atoms of the same period. If an atom is larger, the bond between H-X is weaker, making the base also weaker. Conversely, smaller atoms have stronger H-X bonds, making the base stronger.
by Chem_Mod
Thu Dec 06, 2018 9:52 am
Forum: Bronsted Acids & Bases
Topic: Bronsted Acids and Bases
Replies: 4
Views: 58

Re: Bronsted Acids and Bases

It's helpful to draw the lewis structures to see if the structure is stable enough to either donate or accept a hydrogen. For example, NH4+ is a base because it can only donate a hydrogen. If it accepted a hydrogen, Nitrogen would have 5 bonds, which we know is not possible. Another example is OH-. ...
by Chem_Mod
Thu Dec 06, 2018 9:48 am
Forum: Naming
Topic: Confusion on example
Replies: 1
Views: 13

Re: Confusion on example

The ammines and aquas are neutral, and looking at the roman numeral of cobalt, we see that Cobalt has a +3 charge. We want the overall compound to be neutral, so if Br has a charge of -1, then we would need 3 Br's so that the sum of charges is 0.
by Chem_Mod
Thu Dec 06, 2018 9:46 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing trigonal planar
Replies: 4
Views: 33

Re: Drawing trigonal planar

You do not need to include dashes or wedges in Lewis structures.
by Chem_Mod
Wed Dec 05, 2018 10:16 pm
Forum: Naming
Topic: cyanido vs cyano
Replies: 1
Views: 24

Re: cyanido vs cyano

We will accept both.
See the link/file I created on my class website: Naming Coordination Compounds
by Chem_Mod
Wed Dec 05, 2018 10:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Additional study session/review session on Thursday Dec 6th [ENDORSED]
Replies: 1
Views: 76

Additional study session/review session on Thursday Dec 6th [ENDORSED]

The Neuroscience Undergraduate Society is hosting a study session/review session on Thursday Dec 6th, from 4:30-5:30pm in Gonda Conference room on the first floor.
by Chem_Mod
Wed Dec 05, 2018 8:54 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 7th Edition 6D11
Replies: 1
Views: 21

Re: 7th Edition 6D11

K+ and Br- do not contribute to the pH as they are conjugates of strong acids and bases.
by Chem_Mod
Wed Dec 05, 2018 8:50 pm
Forum: Dipole Moments
Topic: Dipole Moment of C and H
Replies: 3
Views: 36

Re: Dipole Moment of C and H

Who said that we ignore it?
by Chem_Mod
Wed Dec 05, 2018 8:43 pm
Forum: Naming
Topic: Naming shortcuts [ENDORSED]
Replies: 1
Views: 30

Re: Naming shortcuts [ENDORSED]

Naming coordination compounds.PNG
From the textbook.
by Chem_Mod
Wed Dec 05, 2018 8:41 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 3601

Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

Hey guys can someone help me with question 21, I really dont know how to approach this since I just get a formal charge of +2 in total for the ligands which doesnt seem right I will go over this in detail on Friday! -Lyndon But for now.. think about how you would determine the oxidation state of a ...
by Chem_Mod
Wed Dec 05, 2018 2:40 pm
Forum: Lewis Acids & Bases
Topic: Weak and Strong Acids/Bases
Replies: 7
Views: 92

Re: Weak and Strong Acids/Bases

Correction to the above posts: Column 1 and 2, not rows 1/2, make strong bases.
by Chem_Mod
Wed Dec 05, 2018 1:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Class Grading 2
Replies: 4
Views: 78

Re: Class Grading 2

Quoted directly from the Syllabus:

"50% or higher is required to pass with a C- or higher."


Stress no more. :-)
by Chem_Mod
Wed Dec 05, 2018 11:28 am
Forum: Administrative Questions and Class Announcements
Topic: Instructor Evaluations
Replies: 4
Views: 60

Re: Instructor Evaluations

I must remember to announce this in class. :-)
by Chem_Mod
Wed Dec 05, 2018 11:12 am
Forum: Administrative Questions and Class Announcements
Topic: Instructor Evaluations
Replies: 4
Views: 60

Instructor Evaluations

Hi all, Just a quick reminder to fill out your evaluations for TAs and Dr. Lavelle. The feedback from each quarter is used in improving the class for the future! The evaluations close on Saturday so you have the rest of the week. Thanks in advance. For those of you in my discussions, evaluations are...
by Chem_Mod
Wed Dec 05, 2018 10:18 am
Forum: Administrative Questions and Class Announcements
Topic: Final Review seesion - Dec 4th - Anton
Replies: 1
Views: 52

Final Review seesion - Dec 4th - Anton

Attached are the slides for the review session I conducted on December 4th. It covered the examples from the fundamental section.

-Anton
by Chem_Mod
Tue Dec 04, 2018 8:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Questions
Replies: 1
Views: 68

Re: Final Exam Questions

No, it means that at least one question is from those materials. The majority will not be from those materials, but completing those questions is good practice.
by Chem_Mod
Tue Dec 04, 2018 2:08 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: C2 bond??
Replies: 1
Views: 30

Re: C2 bond??

You will be expected to know how to draw Lewis Structures. Due to significant changes in the syllabus, we recommend that you stay away from old course material. Current notes and homework problems are your best resource. Use the course outlines for detailed information on what to know. Bond orders a...
by Chem_Mod
Mon Dec 03, 2018 10:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling practice?
Replies: 1
Views: 36

Re: Sapling practice?

Homework problems are the best resource for practice. You may also find extra assistance and potentially extra problems at office hours, especially workshops and review sessions.
by Chem_Mod
Mon Dec 03, 2018 10:54 pm
Forum: Lewis Acids & Bases
Topic: 6C #19 7th Edition
Replies: 1
Views: 25

Re: 6C #19 7th Edition

Remember that we learned 2 ways to determine relative acid strength. Bond length and stability of the resulting anion. Here, the resulting anion is more stable, with more electron withdrawing effects.
by Chem_Mod
Mon Dec 03, 2018 10:52 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: CH 12 6TH EDITION HW 12.127
Replies: 1
Views: 35

Re: CH 12 6TH EDITION HW 12.127

Rather than directly copying a hw question, you will find better assistance if you discuss your thought process and where you got stuck.
by Chem_Mod
Mon Dec 03, 2018 10:51 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: CH 12 6TH EDITION 12.119 HW
Replies: 1
Views: 39

Re: CH 12 6TH EDITION 12.119 HW

Rather than directly copying a hw question, you will find better assistance if you discuss your thought process and where you got stuck.
by Chem_Mod
Mon Dec 03, 2018 10:50 pm
Forum: Biological Examples
Topic: Structure of a hemoglobin
Replies: 1
Views: 49

Re: Structure of a hemoglobin

A heme group is the Fe bound to the tetradentate porphyrin ligand. In addition to the histidine and O2 molecules, this forms 6 attachments.
by Chem_Mod
Mon Dec 03, 2018 10:43 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Help With 6C.17
Replies: 1
Views: 31

Re: Help With 6C.17

You will not be expected to know pKb values. They will be given, and in the textbook they are given in a table.
by Chem_Mod
Mon Dec 03, 2018 10:42 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Base Notation
Replies: 1
Views: 26

Re: Conjugate Base Notation

Should be fine!
by Chem_Mod
Mon Dec 03, 2018 10:41 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Is there a difference between concentration and molarity?
Replies: 2
Views: 38

Re: Is there a difference between concentration and molarity?

In chemistry, you will most often use molarity M as the units for concentration. (moles/L)
by Chem_Mod
Mon Dec 03, 2018 10:41 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Proton transfer reactions?
Replies: 2
Views: 30

Re: Proton transfer reactions?

The potassium ion is part of the salt and makes no contribution to the pH.
by Chem_Mod
Mon Dec 03, 2018 10:40 pm
Forum: Lewis Acids & Bases
Topic: Base?
Replies: 2
Views: 36

Re: Base?

Strong bases fully ionize or dissociate while weak bases do not and thus have an equilibrium constant kb.
by Chem_Mod
Mon Dec 03, 2018 10:39 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH and Molarity
Replies: 2
Views: 43

Re: pH and Molarity

From part a, a certain number of moles is required to create the solution indicated. However, if the careless technician places that many moles in a larger flask, the solution is essentially diluted with more water. The concentration of hydronium decreases. Therefore the pH will not be the same as i...
by Chem_Mod
Mon Dec 03, 2018 10:37 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: acids and bases
Replies: 3
Views: 55

Re: acids and bases

You should know if acids are strong or weak. One option is to memorize the strong ones, but in general you can find trends to make it easier to determine how strong an acid is.
by Chem_Mod
Mon Dec 03, 2018 3:24 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs. Bronsted
Replies: 5
Views: 31

Re: Lewis vs. Bronsted

Bronsted base: accepts H+(proton) Bronsted acid: gives up H+(proton) Lewis base: donates e- pair to an atom Lewis acid: accepts e- pair from an atom What I did to memorize these is to look at Lewis base and Bronsted base definitions. In Lewis base you are donating electrons to form a bond. In bronst...
by Chem_Mod
Mon Dec 03, 2018 3:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Step Up Session Worksheet (Monday + Friday, Hannah) [ENDORSED]
Replies: 37
Views: 1359

Re: Step Up Session Worksheet (Monday + Friday, Hannah) [ENDORSED]

Here is the worksheet key for Week 9 Topics. Corrections about what I discussed: - I mistakenly said that a square planar coordination compound has two lone pair of electrons while a tetrahedral coordination compound does not. This rule can only be applied to non-d block elements (ie "normal&qu...
by Chem_Mod
Mon Dec 03, 2018 3:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Step Up Session Worksheet (Monday + Friday, Hannah) [ENDORSED]
Replies: 37
Views: 1359

Re: Step Up Session Worksheet (Monday + Friday, Hannah) [ENDORSED]

You said that in order for hydrogen bonding to occur, the hydrogen in the individual molecule has to be bound to either O,N, or F to hydrogen bond with another molecule, but in CH3CH2OCH2CH3, none of the hydrogens are actually bound to the oxygen, but in number 3 d. of this worksheet, it says that ...
by Chem_Mod
Mon Dec 03, 2018 3:17 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Problem 12.19 6th ed
Replies: 3
Views: 39

Re: Problem 12.19 6th ed

Think about how you figure out pH values. What are pH values dependent on? pH values are dependent on the H+ concentration. Thus, if the H+ concentration is reduced, what happens to the pH?
by Chem_Mod
Mon Dec 03, 2018 3:15 pm
Forum: Naming
Topic: Prefix bis, tris, tetrakis, etc. [ENDORSED]
Replies: 5
Views: 102

Re: Prefix bis, tris, tetrakis, etc. [ENDORSED]

You would use this if the compound contains a ligand that has bi- tri- etc. in the name to avoid confusion. For example, palladium (0) tetrakis(triphenylphosphine).
by Chem_Mod
Mon Dec 03, 2018 3:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 9C.5 (7th edition) and polydentates [ENDORSED]
Replies: 1
Views: 59

Re: 9C.5 (7th edition) and polydentates [ENDORSED]

A single oxygen cannot make multiple bonds to the central atom, but multiple oxygens within a compound can. Oxalate could also act as a bidentate, but may not just for that problem specifically.
by Chem_Mod
Mon Dec 03, 2018 3:11 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 7th Edition Focus 9C.5b [ENDORSED]
Replies: 2
Views: 37

Re: 7th Edition Focus 9C.5b [ENDORSED]

This can be a monodentate or a bidentate based on whether only one or both of the oxygens are binding with the central atom. It is big enough to occupy two binding sites, but it does not necessarily need to.
by Chem_Mod
Mon Dec 03, 2018 3:08 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate of oxoacid
Replies: 3
Views: 42

Re: Conjugate of oxoacid

More electronegative atoms withdraw electrons more.
by Chem_Mod
Mon Dec 03, 2018 3:08 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ka Calculations
Replies: 3
Views: 26

Re: Ka Calculations

pka is the -log(Ka). So it is able to be calculated if given then Ka.
by Chem_Mod
Mon Dec 03, 2018 3:07 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Stabilizing an Acid [ENDORSED]
Replies: 1
Views: 47

Re: Stabilizing an Acid [ENDORSED]

The inductive effect (having very electron-withdrawing groups close to the negative charge) will also stabilize acids. For example, phenol is more acidic than you would think compared to other alcohols because the phenyl ring stabilizes the negative charge on the hydroxyl.
by Chem_Mod
Mon Dec 03, 2018 3:05 pm
Forum: Naming
Topic: Regarding the test... [ENDORSED]
Replies: 11
Views: 1300

Re: Regarding the test... [ENDORSED]

Yes, naming coordination compounds wasn't covered last Spring, but Dr. Lavelle did cover it this quarter, so it will be on your final exam.
by Chem_Mod
Mon Dec 03, 2018 3:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands that replace H2O ligands
Replies: 1
Views: 30

Re: Ligands that replace H2O ligands

Ligands that have a higher affinity to form a bond with the transition metal can replace H2O ligands because the H2O ligands do not bind as strongly.
by Chem_Mod
Mon Dec 03, 2018 3:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Community Submissions
Replies: 2
Views: 44

Re: Chemistry Community Submissions

You can click on your id number and navigate your past posts.
by Chem_Mod
Mon Dec 03, 2018 2:59 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ch. 17#33, 6th edition
Replies: 1
Views: 26

Re: Ch. 17#33, 6th edition

Ligand is capable of donating electrons to the central atom so they are either negatively charged or neutral but able to donate a lone pair. For this class, you will only need to know the polydentate ligands that are listed in the table from the textook and all other ligands would be monodentate.
by Chem_Mod
Mon Dec 03, 2018 2:35 pm
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Replies: 135
Views: 23838

Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]

Here is the answer key to the very last worksheet! There is no worksheet 8 because no session was held during week 8 due to thanksgiving break. For #4 on the acids and bases section, see if this helps: [img] Screen%20Shot%202018-12-03%20at%202.27.37%20PM.png [/img] IMPORTANT****** : NAMING of coordi...
by Chem_Mod
Mon Dec 03, 2018 2:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Coordination Compound Notes [ENDORSED]
Replies: 2
Views: 253

Coordination Compound Notes [ENDORSED]

Hi everyone! My name is Ronald, and I am one of your UAs this quarter. Several students in my office hours seemed to be struggling with coordination compounds and naming them, so I've attached my notes/tips, which I hope will help. If there's anything I'm missing, feel free to let me know! I can ans...
by Chem_Mod
Sun Dec 02, 2018 5:53 pm
Forum: Bronsted Acids & Bases
Topic: Help with question 12.127
Replies: 1
Views: 47

Re: Help with question 12.127

Oxygen is stable, with a formal charge of 0. If oxygen were to accept an proton, then either the oxygen will have a positive charge or the double bond would be broken and the carbon would have a positive charge. This would be very unstable for the molecule, and so it is much easier for the nitrogens...
by Chem_Mod
Sun Dec 02, 2018 5:46 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Fundamentals J7
Replies: 5
Views: 97

Re: Fundamentals J7

This question deals with neutralization, which mean that it is a reaction between an acid and a base, whose product is always a salt and water; it also usually involves the combination of H+ and –OH to generate water. Knowing this, you also then know the products of your reaction, which are water an...
by Chem_Mod
Sun Dec 02, 2018 5:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 29

Re: Polydentate

Look at the structure of the ligand, including the formal charges and polarities. Atoms with lone pairs or with formal charges tend to be able to accept or donate electrons. This should help you to figure out which atoms within the ligand can bind to another molecule.
by Chem_Mod
Sun Dec 02, 2018 5:38 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Ligands
Replies: 1
Views: 13

Re: Polydentate Ligands

Look at the structure of the ligand, including the formal charges and polarities. Atoms with lone pairs or with formal charges tend to be able to accept or donate electrons. This should help you to figure out which atoms within the ligand can bind to another molecule.
by Chem_Mod
Sun Dec 02, 2018 5:35 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 3601

FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

The title is called "Churro" so that you can search "Churro" and easily find this post! This is your favorite UA, Lyndon Bui, and I have created many practice problems for your final. The questions are modeled after previous test and exam questions, but it may not have everythin...
by Chem_Mod
Sun Dec 02, 2018 1:52 pm
Forum: Lewis Acids & Bases
Topic: 6th Edition 12.15
Replies: 1
Views: 27

Re: 6th Edition 12.15

Both you and the textbook are partially correct because both are one of the contributors for SO2. It is true that your structure would look more stable because there are no non-zero formal charges, but electrons on SO2 are actually resonating and thus diffused across the entire molecule Refer to thi...
by Chem_Mod
Sat Dec 01, 2018 11:27 am
Forum: Biological Examples
Topic: Coordination compounds and the nervous system [ENDORSED]
Replies: 1
Views: 56

Re: Coordination compounds and the nervous system [ENDORSED]

Not that I am aware of. Interesting question.

If anyone finds an example do post it.
by Chem_Mod
Sat Dec 01, 2018 11:24 am
Forum: Naming
Topic: Naming [ENDORSED]
Replies: 1
Views: 60

Re: Naming [ENDORSED]

Ligand names and their net charges need to be known.

Determing the coordination compound name is what I did in class. Do more examples from the homework, but don't memorize names as they are worked out (not memorized).
by Chem_Mod
Sat Dec 01, 2018 8:38 am
Forum: Bronsted Acids & Bases
Topic: Memorizing Acids and Bases [ENDORSED]
Replies: 2
Views: 55

Re: Memorizing Acids and Bases [ENDORSED]

I covered this in detail in Friday's class.
Make sure to get someone's lecture note and discuss it one of the many peer learning sessions I organized.

Definitely general trends: Metal oxides and hydroxides are basic, etc.
by Chem_Mod
Sat Dec 01, 2018 8:32 am
Forum: Administrative Questions and Class Announcements
Topic: Final [ENDORSED]
Replies: 1
Views: 38

Re: Final [ENDORSED]

No fixed number. It will vary.
by Chem_Mod
Fri Nov 30, 2018 8:52 pm
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Replies: 135
Views: 23838

Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]

Isabel Nakoud 4D wrote:Why does LiCl exhibit greater ionic character than LiBr?


Cl is smaller and is more electronegative than Br, so it will attract electrons better towards itself, leading to greater separation of charge, thus, greater ionic character.

Go to advanced search