Search found 16472 matches

by Chem_Mod
Sun Dec 09, 2018 1:06 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6D.11 7th edition
Replies: 1
Views: 48

Re: 6D.11 7th edition

In each case, the central metal atom can lower the pH by complexing with hydroxide ions, which increases the effective [H+], thereby lowering pH.
by Chem_Mod
Sun Dec 09, 2018 1:05 pm
Forum: Amphoteric Compounds
Topic: HW problem 6.21 (7th edition)
Replies: 1
Views: 37

Re: HW problem 6.21 (7th edition)

Can you please post the full text of the question so everyone can have it in front of them?
by Chem_Mod
Sun Dec 09, 2018 12:59 pm
Forum: Amphoteric Compounds
Topic: How is NH in thymine amphiprotic?
Replies: 1
Views: 42

Re: How is NH in thymine amphiprotic?

Sometimes nitrogens are still willing to give up protons if they have a way of stabilizing the resulting negative charge. Thymine's structure lends it the ability to balance the charge by resonance, whether the charge is positive or negative, so it is find either accepting or giving a proton.
by Chem_Mod
Sun Dec 09, 2018 12:58 pm
Forum: Hybridization
Topic: 4.93
Replies: 2
Views: 54

Re: 4.93

Can you post the question please for reference?
by Chem_Mod
Sun Dec 09, 2018 12:57 pm
Forum: Lewis Structures
Topic: Quantum theory of bonding
Replies: 1
Views: 32

Re: Quantum theory of bonding

Can you explain more about what you mean by the "quantum theory of bonding?"
by Chem_Mod
Sun Dec 09, 2018 10:19 am
Forum: Properties of Light
Topic: HW 1.55A
Replies: 1
Views: 24

Re: HW 1.55A

Please post the question too, but yes you can convert to m.
by Chem_Mod
Sun Dec 09, 2018 10:18 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.5c (7th Edition)
Replies: 1
Views: 17

Re: 6B.5c (7th Edition)

Please post the full question too, but perhaps the concept you are missing is that one mole of that particular base will produce 2 moles if hydroxide ions.
by Chem_Mod
Sun Dec 09, 2018 10:15 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Usuing Rydberg's Equation Conceptually
Replies: 1
Views: 29

Re: Usuing Rydberg's Equation Conceptually

1st clarification: We are not using Rydbergs equation. We use E= -\frac{hR}{n^{2}} The negative is always in this equation which tells us the energy value of each energy level. Emission of a photon means higher to lower energy level which is a negative deltaE but the photon energy is always positive.
by Chem_Mod
Sun Dec 09, 2018 10:11 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Diluted Strong Acids
Replies: 1
Views: 38

Re: Diluted Strong Acids

You will need to know how to calculate pH for strong acid and/or strong base solutions
by Chem_Mod
Sun Dec 09, 2018 9:54 am
Forum: Lewis Acids & Bases
Topic: Identifying Acids and Bases
Replies: 5
Views: 46

Re: Identifying Acids and Bases

F- is a Lewis base because it can donate electrons, such as it picking up hydrogen to form HF.
by Chem_Mod
Sun Dec 09, 2018 9:50 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Electron donating properties of CH3 [ENDORSED]
Replies: 1
Views: 40

Re: Electron donating properties of CH3 [ENDORSED]

CH3 groups are always electron donating. This is just a property of this methyl group.
by Chem_Mod
Sun Dec 09, 2018 9:47 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 7th edition 6C.17 [ENDORSED]
Replies: 1
Views: 39

Re: 7th edition 6C.17 [ENDORSED]

You should be expected to understand, but not inherently know the values of pKa and pKb. The values would be given if necessary on the test. If it has a high pKa, it is a weak acid, strong base. If it has a high pKb, it is a weak base, strong acid.
by Chem_Mod
Sun Dec 09, 2018 9:43 am
Forum: Resonance Structures
Topic: Resonance and Polarity [ENDORSED]
Replies: 1
Views: 31

Re: Resonance and Polarity [ENDORSED]

It depends on the molecule. If we take a HCO2, you would think that the molecule is polar specifically towards the oxygen with the negative charge, it will actually be polar down the middle of the two oxygens because the electrons are delocalized between each oxygen.
by Chem_Mod
Sun Dec 09, 2018 9:41 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Non-chelate polydentate [ENDORSED]
Replies: 1
Views: 36

Re: Non-chelate polydentate [ENDORSED]

Yes, this is possible.
by Chem_Mod
Sun Dec 09, 2018 9:40 am
Forum: Naming
Topic: From today's review session naming en [ENDORSED]
Replies: 1
Views: 32

Re: From today's review session naming en [ENDORSED]

The ammonia groups are in addition to en, not a part of en. They are separate ligands.
by Chem_Mod
Sun Dec 09, 2018 9:39 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Degeneracy of the s orbital [ENDORSED]
Replies: 1
Views: 45

Re: Degeneracy of the s orbital [ENDORSED]

No, the s orbital does not have a degeneracy.
by Chem_Mod
Sun Dec 09, 2018 9:38 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6th edition #12.19 [ENDORSED]
Replies: 1
Views: 52

Re: 6th edition #12.19 [ENDORSED]

If you think about it, let's say the molarity of the initial HCl is 3M. If the final molarity is reduced to 12% of its initial, it will be 3M(.12).

(0.12)(3)=(3)

Therefore, you can cancel out the 3's.
by Chem_Mod
Sun Dec 09, 2018 9:35 am
Forum: Bronsted Acids & Bases
Topic: When creating and acid-base equation [ENDORSED]
Replies: 1
Views: 36

Re: When creating and acid-base equation [ENDORSED]

In general, you should make a salt and water. If you have a strong acid or base, they will dissociate in water. If you have a weak acid and a weak base mixed together, they will form a salt in water.
by Chem_Mod
Sun Dec 09, 2018 9:32 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Lone pairs and polydentate [ENDORSED]
Replies: 1
Views: 45

Re: Lone pairs and polydentate [ENDORSED]

Dentacity is only dependent on how many coordinations the ligand makes to the metal. So if you have SCN-, which can bind by the S or the N, it will still only be monodentate because the linear structure does not allow it to bind to both.
by Chem_Mod
Sun Dec 09, 2018 9:29 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: IMF [ENDORSED]
Replies: 1
Views: 39

Re: IMF [ENDORSED]

Induced dipole is where one molecule with a dipole causes one molecule without a dipole to have a temporary small dipole due to the repulsion of electrons. Dipole-Dipole is where two molecules with dipoles repel each other's electrons, which has a stronger effect.
by Chem_Mod
Sun Dec 09, 2018 9:27 am
Forum: Biological Examples
Topic: Myoglobin? [ENDORSED]
Replies: 1
Views: 44

Re: Myoglobin? [ENDORSED]

Myoglobin can only bind to one oxygen molecule, while Hemoglobin can bind to 4. This is because there is only one heme in myoglobin while hemoglobin has four.
by Chem_Mod
Sun Dec 09, 2018 9:23 am
Forum: *Shrodinger Equation
Topic: Calculations with Schrodinger [ENDORSED]
Replies: 1
Views: 43

Re: Calculations with Schrodinger [ENDORSED]

Correct, you will only have to understand Schrodinger's equation conceptually.
by Chem_Mod
Sun Dec 09, 2018 9:21 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation state [ENDORSED]
Replies: 1
Views: 32

Re: Oxidation state [ENDORSED]

You can't tell the charge of a metal atom by looking at the number of coordinations. You have to look at the overall charge of the coordination compound. This coordination compound, based on the way it is written, must have a +2 charge. However, on an exam, this would be more clear.
by Chem_Mod
Sun Dec 09, 2018 9:16 am
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: shifting equilibrium [ENDORSED]
Replies: 1
Views: 38

Re: shifting equilibrium [ENDORSED]

Equilibrium will shift to reduce the strain on a system. There are a lot of factors that go into this, and you can review them by looking over Le Chatelier's Principle: https://opentextbc.ca/introductorychemistry/chapter/shifting-equilibria-le-chateliers-principle-2/ Essentially, if something is bei...
by Chem_Mod
Sun Dec 09, 2018 9:13 am
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: equilibrium constants [ENDORSED]
Replies: 1
Views: 25

Re: equilibrium constants [ENDORSED]

This depends on whether the system is exothermic or endothermic. If the system is exothermic and temperature increases, the equilibrium will shift left. If it is endothermic and temperature increases, the equilibrium will shift right.
by Chem_Mod
Sun Dec 09, 2018 9:12 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg interdeterminism [ENDORSED]
Replies: 1
Views: 36

Re: Heisenberg interdeterminism [ENDORSED]

Heisenberg's uncertainty principle states that you cannot know the exact position and the exact moment of a particle at any given time. This relates to indeterminism because you are uncertain about the state of the system to some degree at all points in time.
by Chem_Mod
Sun Dec 09, 2018 9:10 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: The 5th shell [ENDORSED]
Replies: 1
Views: 27

Re: The 5th shell [ENDORSED]

The 5th shell has 5s, 5p, 5d, 5f, and 5g orbitals. An s orbital can hold 2, p holds 6, d holds 10, f holds 14, and g holds 18 (which you are not expected to know for this class). If you add them up, you get 50 electrons that the 5th shell can hold. This also follows the 2n^2 rule.
by Chem_Mod
Sun Dec 09, 2018 9:09 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: interference [ENDORSED]
Replies: 1
Views: 21

Re: interference [ENDORSED]

Two waves will produce destructive interference if their wavelengths are out of phase by 180 degrees.
by Chem_Mod
Sun Dec 09, 2018 9:07 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ka/Kb, pKa/pKb [ENDORSED]
Replies: 1
Views: 29

Re: Ka/Kb, pKa/pKb [ENDORSED]

You will not need to know how to calculate these values. You will learn this in 14B. Just understand them conceptually.
by Chem_Mod
Sun Dec 09, 2018 9:04 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polarity of trigonal planar [ENDORSED]
Replies: 1
Views: 36

Re: polarity of trigonal planar [ENDORSED]

The trigonal planar shape is symmetrical, with all atoms being located 120 degrees from each other, meaning that if the atoms attached to the central atom were the same, the molecule would not have one end that was more negative, therefore making it nonpolar. However, not all trigonal planar molecul...
by Chem_Mod
Sun Dec 09, 2018 9:00 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelates [ENDORSED]
Replies: 1
Views: 26

Re: chelates [ENDORSED]

You should be comfortable determining how many areas it would be able to bind to, so you would be expected to know whether it was a tridentate, etc. Remember to look at lone electron pairs that would be able to be shared and will not put strain on the molecule or disrupt formal charge significantly.
by Chem_Mod
Sun Dec 09, 2018 8:58 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: The 5th shell [ENDORSED]
Replies: 1
Views: 17

Re: The 5th shell [ENDORSED]

The 5th shell has 5s, 5p, 5d, 5f, and 5g orbitals. An s orbital can hold 2, p holds 6, d holds 10, f holds 14, and g holds 18 (which you are not expected to know for this class). If you add them up, you get 50 electrons that the 5th shell can hold. This also follows the 2n^2 rule.
by Chem_Mod
Sun Dec 09, 2018 1:52 am
Forum: Bronsted Acids & Bases
Topic: 7th edition fundamentals J.9
Replies: 1
Views: 56

Re: 7th edition fundamentals J.9

Proponoate, CH3CH2COO-
by Chem_Mod
Sun Dec 09, 2018 1:51 am
Forum: Lewis Structures
Topic: Does the Orientation of Surrounding Atoms matter?
Replies: 1
Views: 39

Re: Does the Orientation of Surrounding Atoms matter?

Lewis structures don't show 3-dimensionality. If you wanted to be safe, I don't see why you couldn't.
by Chem_Mod
Sun Dec 09, 2018 1:51 am
Forum: Student Social/Study Group
Topic: Bronsted Bases
Replies: 2
Views: 51

Re: Bronsted Bases

Nice tip.
by Chem_Mod
Sun Dec 09, 2018 1:50 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Oxoacid Strength
Replies: 1
Views: 46

Re: Oxoacid Strength

CH3 is electron-donating, while H is slightly more electronegative.
by Chem_Mod
Sun Dec 09, 2018 1:49 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: dantate of double/single bonded oxygen
Replies: 1
Views: 32

Re: dantate of double/single bonded oxygen

Because of the pi bond between C=O, you wouldn't expect the oxygen lone pair to interact since electron density is delocalized across that double bond.
by Chem_Mod
Sun Dec 09, 2018 1:48 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Polyprotic acids
Replies: 1
Views: 60

Re: Polyprotic acids

Because later forms have more resonance, so it's harder to remove a proton from them since they are more stable.
by Chem_Mod
Sun Dec 09, 2018 1:47 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Conjugate Base versus an Acid
Replies: 2
Views: 65

Re: Conjugate Base versus an Acid

Ka refers to the tendency of ionization of an acid, not a base.
by Chem_Mod
Sun Dec 09, 2018 1:31 am
Forum: Trends in The Periodic Table
Topic: uncertainty principle
Replies: 1
Views: 33

Re: uncertainty principle

Use the Heisenberg's Uncertainty Principle:


p = momentum
x = position
h = Planck's constant
by Chem_Mod
Sun Dec 09, 2018 1:26 am
Forum: Lewis Acids & Bases
Topic: 6th Edition 12.49
Replies: 2
Views: 50

Re: 6th Edition 12.49

The smaller the pKb of a base, the stronger the base. In this case, the pKb of morphine is 5.79, and the pKb of BrO- is 5.31. Therefore, hypobromite is the stronger base.
by Chem_Mod
Sun Dec 09, 2018 1:17 am
Forum: Lewis Acids & Bases
Topic: Question 12.49 (Sixth Edition)
Replies: 1
Views: 35

Re: Question 12.49 (Sixth Edition)

The smaller the pKb of a base, the stronger the base. In this case, the pKb of morphine is 5.79, and the pKb of BrO- is 5.31. Therefore, hypobromite is the stronger base.
by Chem_Mod
Sun Dec 09, 2018 1:14 am
Forum: Lewis Structures
Topic: Lewis structure of sulfur dioxide
Replies: 1
Views: 27

Re: Lewis structure of sulfur dioxide

Sulfur can be drawn with double bonds, and this would give the molecule an overall charge of 0 for its formal charge. However, 12.15 is asking for the interaction between Cl- and SO2. Cl- would not interact with SO2 if it were neutral, so that is why the solution manual has it written so that there ...
by Chem_Mod
Sat Dec 08, 2018 11:49 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]

So when calculating the pH of an acid and base reaction, would you need to put both into one equation or write equations separately for each? Answer: When finding pH, you have to figure out concentrations of hydronium or hydroxide ions. The equation is for your own understanding of mole to mole rat...
by Chem_Mod
Sat Dec 08, 2018 11:28 pm
Forum: Lewis Acids & Bases
Topic: water as a lewis base
Replies: 1
Views: 28

Re: water as a lewis base

Water is amphoteric and can act as a base or an acid both.
by Chem_Mod
Sat Dec 08, 2018 11:27 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: test 2 question 1 (nitrogen gas molecule)
Replies: 3
Views: 32

Re: test 2 question 1 (nitrogen gas molecule)

Please make another post with the actual question.
by Chem_Mod
Sat Dec 08, 2018 11:26 pm
Forum: Conjugate Acids & Bases
Topic: HCO3- an acid or base
Replies: 2
Views: 25

Re: HCO3- an acid or base

It can act as both, either giving off a proton or accepting a proton. H2CO3 is a polyprotic acid so an equilibrium will form with all the forms.
by Chem_Mod
Sat Dec 08, 2018 11:23 pm
Forum: Hybridization
Topic: The D Orbital
Replies: 1
Views: 31

Re: The D Orbital

As it is an unhybridized orbital, you will often see it involved in pi bond formation.
by Chem_Mod
Sat Dec 08, 2018 11:23 pm
Forum: Amphoteric Compounds
Topic: Amphiprotic and Amphoteric
Replies: 1
Views: 39

Re: Amphiprotic and Amphoteric

There are few examples that are biologically useful/common, but they involve acid base transfers that do not involve protons.
by Chem_Mod
Sat Dec 08, 2018 10:36 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: Hydrogen Bonding
Replies: 3
Views: 36

Re: Hydrogen Bonding

If the hydrogen is covalently bound to F,O,N then it can form a hydrogen bond. A hydrogen on CH4 for example cannot be involved in hydrogen bonding because it is NOT covalently bound to a F,O,N, it is covalently bound to a C
by Chem_Mod
Sat Dec 08, 2018 10:34 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: HOMO; LUMO
Replies: 1
Views: 25

Re: HOMO; LUMO

Not covered this quarter. See syllabus and course outlines for details on covered material.
by Chem_Mod
Sat Dec 08, 2018 10:33 pm
Forum: Trends in The Periodic Table
Topic: ionization energy
Replies: 2
Views: 23

Re: ionization energy

Correct
by Chem_Mod
Sat Dec 08, 2018 5:58 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids vs. Number of Oxygens
Replies: 3
Views: 44

Re: Strength of Acids vs. Number of Oxygens

Strength of acids can be determined by bond length with the acidic proton, and stability of the resulting anion. OXygens are electron withdrawing atoms which help stabilize the anion and its formal charge.
by Chem_Mod
Sat Dec 08, 2018 5:56 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculation Concentration
Replies: 1
Views: 34

Re: Calculation Concentration

Concentration is mol/L or Molarity. So determine the moles and total volume to find concentration of anything.
by Chem_Mod
Sat Dec 08, 2018 5:55 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate
Replies: 2
Views: 33

Re: polydentate

Not quite. Generally atoms like Nitrogen and oxygen can act as binding sites if they have a lone pair and are in the correct orientation.
by Chem_Mod
Sat Dec 08, 2018 5:50 pm
Forum: Lewis Acids & Bases
Topic: Amphiprotic vs. Amphoteric
Replies: 1
Views: 19

Re: Amphiprotic vs. Amphoteric

There is a general diagonal trend for oxides that separate acids and bases.
by Chem_Mod
Sat Dec 08, 2018 5:49 pm
Forum: Bronsted Acids & Bases
Topic: H vs OH
Replies: 3
Views: 36

Re: H vs OH

There is no definite trend that states this. Covalent bond strength can be determined by examining bond length.
by Chem_Mod
Sat Dec 08, 2018 5:41 pm
Forum: Coordinate Covalent Bonds
Topic: Myoglobin
Replies: 1
Views: 42

Re: Myoglobin

Hemoglobin by definition is composed of four myoglobins. Myoglobin is a Fe coordination complex that has 5 bonds. Fe prefers to have 6 bonds, and the extra spot can bind a molecule of O2.
by Chem_Mod
Sat Dec 08, 2018 10:45 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating change in pH after dilution [ENDORSED]
Replies: 2
Views: 76

Re: Calculating change in pH after dilution [ENDORSED]

Since pH = -log [H+] of a given solution, we can set pH old = -log [H+]old and pH new = -log [H+] new. From the wording of the problem, we know that [H+]new = [H+]old*0.12. As a result, if you take the -log of both sides of the equation, pH new = pH old + (-log 0.12) (keep in mind the rule log (A*B)...
by Chem_Mod
Sat Dec 08, 2018 10:38 am
Forum: Electronegativity
Topic: Electronegativity Trend
Replies: 1
Views: 23

Re: Electronegativity Trend

As you go across the period, the valence electrons of the element is closer to achieving a full octect if it steals a few more electrons. On other end of the period, the elements only have a few valence electrons on the outer most layer so it is easier to lose those electrons to gain a full octet. T...
by Chem_Mod
Sat Dec 08, 2018 10:29 am
Forum: Identifying Acidic & Basic Salts
Topic: Weak Lewis Acids
Replies: 1
Views: 26

Re: Weak Lewis Acids

When we are looking at proton donation, we are regarding them as Bronsted-Lowry acid or base. When we are looking at electron donation, we are referring to them as Lewis acid/base. Lewis acid/base is a more comprehensive theory that include Bronsted-Lowry acid/base. In other words, if a acid or base...
by Chem_Mod
Sat Dec 08, 2018 10:23 am
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Replies: 135
Views: 23837

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

Karishma_1G wrote:On Worksheet 9, question #6, why would acid 2 be stronger than acid 4?


The CH3 groups in acid 4 has electron donating properties, which deems it a stronger acid by the electronegativity trend.
by Chem_Mod
Sat Dec 08, 2018 10:23 am
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Replies: 135
Views: 23837

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

Karishma_1G wrote:On Worksheet 9, question #6, why would acid 2 be stronger than acid 4?


The CH3 groups in acid 4 has electron donating properties, which deems it a stronger acid by the electronegativity trend.
by Chem_Mod
Sat Dec 08, 2018 10:21 am
Forum: Administrative Questions and Class Announcements
Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Replies: 135
Views: 23837

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

Im just wondering why the tail has a -1 charge since for me when I calculated the formal charges of the nitrogens connected to Co I got +1, +1, +1, +1, and 0 Wouldnt that give an overall +4 charge for the tail? For the tail itself, you need to think about it when it's removed from the Co, so break ...
by Chem_Mod
Sat Dec 08, 2018 10:04 am
Forum: General Science Questions
Topic: Can We Take The Final In Pencil?
Replies: 8
Views: 118

Re: Can We Take The Final In Pencil?

That's correct, the final must be written in pen.
by Chem_Mod
Sat Dec 08, 2018 9:55 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Oxygen atoms in acid structures?
Replies: 3
Views: 36

Re: Oxygen atoms in acid structures?

This has to do with resonance. The more oxygens, the more double bonds. You can draw out the Lewis structures for yourself if necessary. If there is more resonance, then the negative charge on the oxygen that results from losing a proton is better stabilized. Since the conjugate base is more stable,...
by Chem_Mod
Sat Dec 08, 2018 9:47 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong Acids
Replies: 5
Views: 44

Re: Strong Acids

There are no weak acid/base calculations in 14A. Strong acid/base calculations will be tested only.
by Chem_Mod
Sat Dec 08, 2018 9:43 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: molarity and acid base calcs
Replies: 1
Views: 36

Re: molarity and acid base calcs

The problem asks for the new pH that was diluted. As such, you need to calculate the new concentration to plug into -log. The calculation inside the log is m1v1=m2v2 rearranged.
by Chem_Mod
Sat Dec 08, 2018 9:40 am
Forum: Bronsted Acids & Bases
Topic: Bronsted Acids and Bases
Replies: 4
Views: 58

Re: Bronsted Acids and Bases

NH4+ will act as an acid, since it will donate protons. It will not act as a base. It is impossible for it to accept any more protons, since that would make NH5 2+. Nitrogen cannot have more than an octet.
by Chem_Mod
Sat Dec 08, 2018 9:38 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable
Replies: 4
Views: 67

Re: Polarizable

No, Cs+ does not have the highest polarizing power. Li+ and the ion with the more polarizability, I- would form bonds with the most ionic character.
by Chem_Mod
Sat Dec 08, 2018 7:16 am
Forum: Biological Examples
Topic: Myoglobin [ENDORSED]
Replies: 3
Views: 107

Re: Myoglobin [ENDORSED]

The iron atom in myoglobin has six bonds but is not hexadentate as it binds to three different ligands.

Hexadentate means one ligand that forms six bonds.
The only hexadentate ligand I discussed in class is EDTA.
by Chem_Mod
Sat Dec 08, 2018 7:08 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Ch 17: Coordination Compounds worksheet [ENDORSED]
Replies: 1
Views: 56

Re: Ch 17: Coordination Compounds worksheet [ENDORSED]

Please post/upload image.

See the instructions I created to post images with questions:
viewtopic.php?f=176&t=3916
by Chem_Mod
Sat Dec 08, 2018 7:04 am
Forum: General Science Questions
Topic: tips on memorizing ligands [ENDORSED]
Replies: 1
Views: 69

Re: tips on memorizing ligands [ENDORSED]

This file on my class website should help:
Naming Coordination Compounds (https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/NamingCoordinationCompounds.pdf)
by Chem_Mod
Sat Dec 08, 2018 1:38 am
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]

Answers are posted now at the top. Scroll up:)
by Chem_Mod
Sat Dec 08, 2018 12:21 am
Forum: Biological Examples
Topic: Guanine [ENDORSED]
Replies: 2
Views: 58

Re: Guanine [ENDORSED]

As I showed in class guanine nitrogen has available lone pair on nitrogen atom.
by Chem_Mod
Sat Dec 08, 2018 12:14 am
Forum: Bronsted Acids & Bases
Topic: Biological Compounds [ENDORSED]
Replies: 1
Views: 49

Re: Biological Compounds [ENDORSED]

What was covered in class and in the required reading from the textbook.
by Chem_Mod
Sat Dec 08, 2018 12:11 am
Forum: Ionic & Covalent Bonds
Topic: Test bank?
Replies: 9
Views: 115

Re: Test bank?

Homework problems are the best preparation.

Also, as stated in the syllabus one question will come directly from the homework.
by Chem_Mod
Fri Dec 07, 2018 11:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Test Keys [ENDORSED]
Replies: 2
Views: 77

Re: Test Keys [ENDORSED]

They are and were discussed in review sessions and office hours, etc. 76 hours this week to discuss them.
by Chem_Mod
Fri Dec 07, 2018 11:52 pm
Forum: Biological Examples
Topic: Hemoglobin Myoglobin details for test
Replies: 1
Views: 33

Re: Hemoglobin Myoglobin details for test

What was covered in class and in the required textbook reading.
by Chem_Mod
Fri Dec 07, 2018 11:23 pm
Forum: Naming
Topic: Week 10 Discussion Notes (3A,3I,3K)
Replies: 1
Views: 155

Week 10 Discussion Notes (3A,3I,3K)

Hi all,

Attached please find notes and worksheet for week 10.

Good luck on your finals!! ٩(๑>◡<๑)۶

Best,
Joyce
by Chem_Mod
Fri Dec 07, 2018 8:22 pm
Forum: General Science Questions
Topic: do we need to memorize strong acids and bases [ENDORSED]
Replies: 1
Views: 56

Re: do we need to memorize strong acids and bases [ENDORSED]

I covered them in class in detail, yes.
by Chem_Mod
Fri Dec 07, 2018 5:03 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: equilibrium table [ENDORSED]
Replies: 1
Views: 723

Re: equilibrium table [ENDORSED]

Yes, any reaction. But this is a topic that I will cover in Chem 14B. In Chem 14B I will show how to use equilibrium tables to calculate pH of weak acids and weak bases. In Chem 14A we don't need to use equilibrium tables to calculate pH of strong acids and strong bases as we can assume they are 100...
by Chem_Mod
Fri Dec 07, 2018 12:08 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]

Yes, you are correct. We need H-X (where X = N, O, F) on one molecule because this allows H to have a partial positive charge due to the high electronegativity of N, O, or F. We need another molecule to have X so that there's a partial negative charge on that atom. These partial charges attract each...
by Chem_Mod
Fri Dec 07, 2018 1:00 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 1
Views: 13

Re: Polarity

First, draw the Lewis structure. Then, identify all the dipole moments (ie is one atom more electronegative than its neighbor?). Lastly, determine if there's a net dipole moment. If all the dipole moments cancel, then it's nonpolar. If there's a net dipole moment, then it's polar.
by Chem_Mod
Fri Dec 07, 2018 12:59 am
Forum: Administrative Questions and Class Announcements
Topic: Lavelle's review
Replies: 1
Views: 38

Re: Lavelle's review

All review sessions during class will cover the same material.
by Chem_Mod
Fri Dec 07, 2018 12:58 am
Forum: Naming
Topic: Chloro v/s chlorido
Replies: 6
Views: 50

Re: Chloro v/s chlorido

Both are acceptable. One is just newer according to IUPAC naming conventions.
by Chem_Mod
Fri Dec 07, 2018 12:56 am
Forum: Biological Examples
Topic: Shape of Myoglobin
Replies: 3
Views: 19

Re: Shape of Myoglobin

When oxygen is bound, then yes, it would be octahedral.
by Chem_Mod
Fri Dec 07, 2018 12:54 am
Forum: Ionic & Covalent Bonds
Topic: Most Ionic Bond (2.D.3 7th ed)
Replies: 1
Views: 23

Re: Most Ionic Bond (2.D.3 7th ed)

The most significant difference between Be and Ba is the size. Ba is much further down on the periodic table and has a larger atomic radius. Ba can't hold onto its electrons as tightly as Be because the electrons are so far. This makes Br more likely to take those electrons.
by Chem_Mod
Fri Dec 07, 2018 12:46 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Fundamentals J.7b 6th Edition
Replies: 1
Views: 19

Re: Fundamentals J.7b 6th Edition

Zinc has a charge of +2, so you would need 2 OH- to make the overall charge 0. Once you have Zn(OH)2, balance the equation.
by Chem_Mod
Fri Dec 07, 2018 12:43 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Problem 12.25 6th edition
Replies: 1
Views: 25

Re: Problem 12.25 6th edition

First, you must find the molarity of Ba(OH)2. Review fundamentals from the very beginning of the quarter.
For every one mole of Ba(OH)2 you have, you also have 2 moles of OH. Calculate [OH-].
Use Kw equation where [H+][OH-]=Kw to solve for H+.
by Chem_Mod
Thu Dec 06, 2018 10:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: S orbitals lower energy than p orbitals
Replies: 2
Views: 49

Re: S orbitals lower energy than p orbitals

It takes energy to separate opposite charges. Thus, an electron farther away from the nucleus would have more energy.
by Chem_Mod
Thu Dec 06, 2018 9:46 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6D 11 e) and f)
Replies: 2
Views: 71

Re: 6D 11 e) and f)

Could you provide more information? What exactly are the reactants?
by Chem_Mod
Thu Dec 06, 2018 9:44 pm
Forum: Lewis Acids & Bases
Topic: Determining which H^+ ions are given off
Replies: 4
Views: 36

Re: Determining which H^+ ions are given off

It depends on the molecule. You have to review the stability gained after losing the proton afterwards. The one that yields the more stable molecule after deprotonation is the best answer.
by Chem_Mod
Thu Dec 06, 2018 9:43 pm
Forum: Amphoteric Compounds
Topic: 7th ed. 6A17
Replies: 3
Views: 44

Re: 7th ed. 6A17

It's fairly close to metalloids, so yes.
by Chem_Mod
Thu Dec 06, 2018 9:42 pm
Forum: Bronsted Acids & Bases
Topic: 7th ed. 6A9
Replies: 2
Views: 38

Re: 7th ed. 6A9

Could you provide more information, like the reaction specifically being discussed?

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