Search found 129 matches

by Vincent Leong 2B
Sat Jan 25, 2020 5:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: sign changes in bond enthalpy
Replies: 5
Views: 18

Re: sign changes in bond enthalpy

you can refer to hess's law to explain why delta H is positive or negative. The formula involving the summation of products minus the summation of reactants should indicate where heat lies in the reaction and whether bonds are being broken or formed.
by Vincent Leong 2B
Sat Jan 25, 2020 4:59 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: standard enthalpy
Replies: 3
Views: 13

Re: standard enthalpy

Elements in their standard state are not formed, they just are. That's the why technically don't have a delta H of formation value. They just naturally exist in that form and so they don't require energy to form.
by Vincent Leong 2B
Sat Jan 25, 2020 4:56 pm
Forum: Phase Changes & Related Calculations
Topic: State Function vs. Intensive + Extensive Properties
Replies: 2
Views: 11

State Function vs. Intensive + Extensive Properties

Is the concept of intensive and extensive properties similar to the concept of state function? If not, what's the difference between the two terms?
by Vincent Leong 2B
Sat Jan 25, 2020 4:54 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Decreasing volume
Replies: 5
Views: 18

Re: Decreasing volume

It's helpful to think of decreasing/increasing V or increasing/decreasing P in terms of Q and K. When you change the volume (basically changing the pressure), you're changing the Q value and whether the new Q is larger or lesser than K, you know which way the reaction will shift.
by Vincent Leong 2B
Sat Jan 25, 2020 4:52 pm
Forum: Phase Changes & Related Calculations
Topic: Calculating Bond Enthalpies
Replies: 4
Views: 7

Re: Calculating Bond Enthalpies

There will be a given table of bond enthalpy values that you can use to ultimately calculate delta H.
by Vincent Leong 2B
Sat Jan 25, 2020 4:43 pm
Forum: Phase Changes & Related Calculations
Topic: Bond Enthalpies
Replies: 5
Views: 12

Re: Bond Enthalpies

Bond enthalpies are calculated averages with the exception of diatomic molecules (ex. H2, O2, N2) which are exact measurements.
by Vincent Leong 2B
Thu Jan 23, 2020 2:25 pm
Forum: Ideal Gases
Topic: ICE table approximation
Replies: 10
Views: 19

Re: ICE table approximation

The approximation is only used when K is small enough and you know this approximation works if the x you solve for is < 5% of the initial concentration.
by Vincent Leong 2B
Thu Jan 23, 2020 2:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Buffers
Replies: 3
Views: 14

Re: Buffers

There are several types of solutions that will produce buffers but the only one we've covered is a salt with a weak conjugate acid/base and a weak acid/base.
by Vincent Leong 2B
Thu Jan 23, 2020 2:22 pm
Forum: Ideal Gases
Topic: test 1
Replies: 9
Views: 32

Re: test 1

No the test only includes chemical and acid/base equilibrium
by Vincent Leong 2B
Thu Jan 23, 2020 2:21 pm
Forum: Ideal Gases
Topic: solids and K
Replies: 8
Views: 17

Re: solids and K

Their concentrations just don't differ when transitioning from the initial to equilibrium. In essence, if you were to include them into the K constant, it would essentially be 1 or negligible.
by Vincent Leong 2B
Thu Jan 23, 2020 2:19 pm
Forum: Phase Changes & Related Calculations
Topic: - and + H values
Replies: 5
Views: 26

Re: - and + H values

If you think about it logically, it requires energy to break chemical bonds. If it takes energy to break bonds, energy must be absorbed by the reactants to break those bonds and so that energy comes in the form of heat. If the enthalpy of the reaction or delta H is positive, it means more energy is ...
by Vincent Leong 2B
Thu Jan 23, 2020 2:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium 1B Post-Assessment #19.b
Replies: 2
Views: 11

Re: Chemical Equilibrium 1B Post-Assessment #19.b

This question is testing the concept that Kreverse = 1/Kforward. Because the Chinese researcher flipped the initial reaction, the K constant of the chinese researchers reaction will be the inverse of the K constant calculated in the first part of the question., which should be answer D
by Vincent Leong 2B
Sun Jan 19, 2020 5:54 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endo vs. Exothermic
Replies: 5
Views: 15

Re: Endo vs. Exothermic

bond forming = exothermic = n2 + h2 --> nh3

bond breaking = endothermic = PCl5 --> PCl3 + Cl2
by Vincent Leong 2B
Sun Jan 19, 2020 5:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pKa
Replies: 13
Views: 21

Re: pKa

high pka = low ka = weak acid
low pka = high ka = strong acid
by Vincent Leong 2B
Sun Jan 19, 2020 5:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: small Ka
Replies: 5
Views: 14

Re: small Ka

Weak acids are the only types of acids that we'll consider Ka values. In strong acids, there will be no Ka value because it will always be undefined as the acid will dissociate completely, leaving no concentration of reactant left.
by Vincent Leong 2B
Sun Jan 19, 2020 5:47 pm
Forum: Administrative Questions and Class Announcements
Topic: final exam
Replies: 6
Views: 34

Re: final exam

I believe its by the end of this week in some room in young hall. make sure to ask Dr. Lavelle about it on wednesday or check for his old email about it
by Vincent Leong 2B
Thu Jan 16, 2020 7:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Exponents and the K constant
Replies: 4
Views: 31

Exponents and the K constant

Why do we use the coefficients in a reaction as exponents in the K constant? What do they imply?
by Vincent Leong 2B
Thu Jan 16, 2020 7:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Equilibrium
Replies: 9
Views: 27

Solids and Equilibrium

Do solids and liquids affect equilibrium and but not the equilibrium constant or does it have no impact on both? Why?
by Vincent Leong 2B
Thu Jan 16, 2020 5:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kb and pKb
Replies: 2
Views: 15

Re: Kb and pKb

Just focus on Kb and the logic of how pkB is related to pOH or pH should follow. Kb is a measure of how strong a base truly is. The larger the Kb is, the more basic a molecule is meaning that the larger the Kb, the more products (OH- and ion) that forms or the more readily it dissociates. If you hav...
by Vincent Leong 2B
Thu Jan 16, 2020 5:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Negative pH
Replies: 6
Views: 18

Re: Negative pH

Yes, a pH can be below 0. This just tells us that the molarity of hydrogen ions is greater than 1. Theoretically it is possible but in a lab, that can rarely be observed.
by Vincent Leong 2B
Thu Jan 16, 2020 5:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acid/ Base Ionization
Replies: 2
Views: 19

Re: Acid/ Base Ionization

They ionize completely because the H+ ion attached to them fully dissociates into 2 separate molecules. When looking at their ice table, their x variable is equal to the initial concentration of a reactant. This is what defines a strong acid or base: their ability to fully dissociate into its ionic ...
by Vincent Leong 2B
Thu Jan 16, 2020 5:43 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas and Le Chatliers
Replies: 7
Views: 23

Re: Inert Gas and Le Chatliers

inert gases don't react with the reactants so they ultimately don't consume the partial pressure or the concentration of the reactants. The fact that partial pressure of the reactants (which directly impacts the K constant) is not effected, the K constant is therefore not effected.
by Vincent Leong 2B
Thu Jan 16, 2020 2:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximation
Replies: 2
Views: 11

Re: Approximation

Typically, yes, if K is less than 10^-3 it is small and so that x variable in the K constant expression is negligible and so you can solve for x without the use of a quadratic formula. The key to knowing if this method works is checking if the "x" variable you solved for divided by the ini...
by Vincent Leong 2B
Thu Jan 16, 2020 2:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Protonation & Deprotonation
Replies: 9
Views: 32

Re: Protonation & Deprotonation

To calculate % deprotonation (because this is the most common factor that questions ask for), 1) solve for the x variable in the ICE table 2) put x over the initial concentration (Divide x by initial concentration: x/[R]) 3) multiply by 100 to convert that to number to a % 4) that is your % deproton...
by Vincent Leong 2B
Thu Jan 16, 2020 2:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.7
Replies: 2
Views: 28

Re: 6D.7

You have to know the Ka value of both compounds to find the initial concentration. Given pH, you can only determine the concentration of H3O+, OH-, pOH, and probably other products but never the initial concentration by given just the solutions pH.
by Vincent Leong 2B
Sun Jan 12, 2020 8:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Thinking point 5J
Replies: 4
Views: 19

Re: Thinking point 5J

No change; solids are pure substances and their changes in concentration are insignificant so we don't include them in the equilibrium constants.
by Vincent Leong 2B
Sun Jan 12, 2020 8:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Inert Gases
Replies: 4
Views: 14

Re: Inert Gases

I believe N2 and H2 are inert gases as well.
by Vincent Leong 2B
Sun Jan 12, 2020 8:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Comparing K Values
Replies: 4
Views: 32

Re: Comparing K Values

K values represent how easily it is to create or break bonds. When you break down a compound, for example, PCl5 to Cl2 and PCl3 and the K constant is 111111. That number is very high, meaning there is more products than reactants at equilibrium and thus the bonds of PCl5 can be easily broken and thu...
by Vincent Leong 2B
Sun Jan 12, 2020 7:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp
Replies: 6
Views: 23

Re: Kp

Yes, Kp is only used with gases
by Vincent Leong 2B
Sun Jan 12, 2020 7:57 pm
Forum: Ideal Gases
Topic: Le Chatelier's Principle
Replies: 7
Views: 44

Re: Le Chatelier's Principle

Le chatlier's basically tells us that a reaction will shift towards either the right or left (product or reactant formation) in order to alleviate the stress placed on the reaction. The reaction behaves in this way because one something is added or taken away from a reaction, it placed the reaction ...
by Vincent Leong 2B
Sun Jan 12, 2020 7:50 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Pure Substances
Replies: 3
Views: 26

Re: Pure Substances

I can't give a clear explaination for gases but I know for aqueous solutions there will always be a solution and a solvent since aqueous means that that molecule can be dissolved by something. Having this in mind, this molecule doesnt have bonds strong enough compared to solids and liquids to consis...
by Vincent Leong 2B
Thu Jan 09, 2020 8:08 pm
Forum: Ideal Gases
Topic: Understanding equilibrium
Replies: 2
Views: 13

Re: Understanding equilibrium

When we use equilibrium constants, it is usually for weak or unstable compounds. Think of it in terms of weak acids or bases (which we mainly use K constants for), when a weak acid breaks down into H+ ions and its conjugate base, the products (H+ and that conjugate base) continue to react and actual...
by Vincent Leong 2B
Thu Jan 09, 2020 8:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Volume and Equilibrium
Replies: 3
Views: 13

Re: Volume and Equilibrium

Changing the volumes changes the concentrations at equilibrium but do not, however, change the equilibrium constant. The equilibrium constant only changes if temperature changes.
by Vincent Leong 2B
Wed Jan 08, 2020 6:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure
Replies: 3
Views: 38

Re: Partial Pressure

Remember that the only thing that remains constant is the equilibrium constant value. As long as you put the reaction under the same testing conditions (which should be constant temp) the equilibrium constant will remain the same. Do the ICE table to reason how initial amounts eventually affect the ...
by Vincent Leong 2B
Wed Jan 08, 2020 6:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5I.13
Replies: 1
Views: 46

Re: 5I.13

Cl2 is the more thermodynamically stable RELATIVE to its atoms because it has a lower K value. This indicates that there are more reactants or that more Cl2 exists than Cl and that means that less bonds of Cl2 are broken compared to F2. This indicates that relative to its atoms, Cl2 is more intact o...
by Vincent Leong 2B
Wed Jan 08, 2020 6:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressures
Replies: 4
Views: 21

Re: Partial Pressures

No, they do not need to add up to 1. There is no minimum or maximum when considering partial pressures and calculating the equilibrium constant.
by Vincent Leong 2B
Wed Jan 08, 2020 6:11 pm
Forum: Ideal Gases
Topic: Understanding Q
Replies: 13
Views: 61

Re: Understanding Q

In the reaction, whether it's at equilibrium or not, solids and liquids are pure substances. This means, that no matter how the reaction goes, the overall reaction will not change the substance significantly enough for its concentration to change. That is why at equilibrium (for K constant) and the ...
by Vincent Leong 2B
Wed Jan 08, 2020 6:07 pm
Forum: Ideal Gases
Topic: K
Replies: 10
Views: 49

Re: K

The only thing that affects the equilibrium constant or the equilibrium conditions of the reaction is temperature. Understanding the E in the ICE table also helps when explaining why this is or how initial concentration/partial pressures will impact the concentrations/partial pressures of products a...
by Vincent Leong 2B
Sun Dec 08, 2019 8:33 pm
Forum: Lewis Acids & Bases
Topic: What does it mean when something is strong?
Replies: 8
Views: 53

Re: What does it mean when something is strong?

the acid or base will dissociate completely. For acids, it will give away all of its H+ ions and bases will give off it's OH- completely. After being dissolved in water, there will be nothing left of that acid or base in terms of concentration.
by Vincent Leong 2B
Sun Dec 08, 2019 8:32 pm
Forum: Lewis Acids & Bases
Topic: respiratory acidosis
Replies: 2
Views: 35

Re: respiratory acidosis

↓respiration = ↑ CO2 + H2CO3 = ↓ HCO3 : H2CO3 = ↓blood pH

*Caused by CO2 or the imbalance of H2CO3
by Vincent Leong 2B
Sun Dec 08, 2019 8:31 pm
Forum: Lewis Acids & Bases
Topic: B(OH)3 problem 6.13
Replies: 2
Views: 34

Re: B(OH)3 problem 6.13

Boron is one of those elements that have exception to the octect rule in that it doesn't fill it's complete octect. It's missing lone pair on Boron suggests that it's indeed an electron acceptor or in other terms a Lewis acid.
by Vincent Leong 2B
Sun Dec 08, 2019 8:29 pm
Forum: Amphoteric Compounds
Topic: Memorization?
Replies: 4
Views: 59

Re: Memorization?

Memorizing the oxides (group 1 and 2 and all the nonmetals) and that great acids and bases are generally good. The ones that aren't in that list would be considered amphoteric. This is generally how I like to think of it.
by Vincent Leong 2B
Sun Dec 08, 2019 8:28 pm
Forum: Amphoteric Compounds
Topic: As2O and Bi2O3
Replies: 4
Views: 34

Re: As2O and Bi2O3

We can also distinguish their amphoteric nature from looking at their lewis structures. Although it is easier to know that since they border the metalloid line, they will have amphoteric properties
by Vincent Leong 2B
Sat Dec 07, 2019 7:54 pm
Forum: Trends in The Periodic Table
Topic: Exceptions to Electronegativity
Replies: 3
Views: 44

Re: Exceptions to Electronegativity

no. There are exception to the atomic radius and ionization energy trend however.
by Vincent Leong 2B
Sat Dec 07, 2019 2:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Disobeying the octect rule
Replies: 4
Views: 37

Disobeying the octect rule

Is it safe to safe that all period 3 elements and below (period 4,5,6,...) disobeye the octect rule? I was just wondering why SO2 has two doubles formed with oxygen and a lone pair on the S. I thought S would want to fulfill it's octect still, not go above it
by Vincent Leong 2B
Sat Dec 07, 2019 1:28 pm
Forum: Biological Examples
Topic: Vitamin b12
Replies: 1
Views: 31

Vitamin b12

What does vitamin b12 do for us? Knowing that Cobalt makes up vitamin b12, what can we infer about it? Is there a table that includes these transition metals significance that we can refer to?
by Vincent Leong 2B
Fri Dec 06, 2019 4:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2.63
Replies: 1
Views: 25

Re: 2.63

AX2E2 has a bond angle of 104.5 or <109.5
by Vincent Leong 2B
Fri Dec 06, 2019 3:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: AX4 geometry in coordination comppounds
Replies: 2
Views: 21

AX4 geometry in coordination comppounds

When transition metal complexes have a coordination number of 4 or the coordination compound generally has this AX4 geometry, do we refer to the shape as "square planar or tetrahedral" or simply "tetrahedral" or "square planar"? If it's the latter, how can we differenti...
by Vincent Leong 2B
Thu Dec 05, 2019 10:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Nitrosyl lewis structure
Replies: 1
Views: 14

Re: Nitrosyl lewis structure

the radical shouldn't be drawn in the lewis structure in relation to the entire coordination compound. That lone electron should be held within single bond between the N atom and carbon chain it's bonded to or the transition metal complex it's bonded to. That way, nitrogen has 3 bonded electron pair...
by Vincent Leong 2B
Thu Dec 05, 2019 10:47 pm
Forum: Naming
Topic: Using alternate Greek prefixes
Replies: 2
Views: 18

Re: Using alternate Greek prefixes

I'd say your best bet is looking at the lewis structure of the ligand and counting the amount of lone pairs, especially on nitrogen atoms, and counting them as regions where it can latch onto a transition metal complex. As long as the center transition metal has more than 1 bond formed, it will be p...
by Vincent Leong 2B
Thu Dec 05, 2019 6:41 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Pd exception
Replies: 1
Views: 39

Pd exception

Do we need to know that Pd has an exception to its electron configuration (it's actually [Kr] 3d10 instead of [Kr]3d8 4s2)? what are the exceptions we do need to know?
by Vincent Leong 2B
Thu Dec 05, 2019 6:39 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of CH3 e- withdrawing power
Replies: 1
Views: 34

Strength of CH3 e- withdrawing power

why do H atoms have a stronger e- withdrawing power than the functional group CH3?
by Vincent Leong 2B
Thu Dec 05, 2019 12:57 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6C.19
Replies: 3
Views: 48

Re: 6C.19

I think there's a table at the end of section 6C that explains the reasoning for these trends and comparisons perfectly. I highly recommend looking at that table because it helped me a lot with these questions.
by Vincent Leong 2B
Thu Dec 05, 2019 12:55 pm
Forum: Calculating the pH of Salt Solutions
Topic: Final Content [ENDORSED]
Replies: 1
Views: 86

Final Content [ENDORSED]

Just to make sure, we're responsible for knowing how to calculate the pH of salt solutions, strong acids + weak base solutions (vice versa), and strong acid/base solutions. Not buffer solutions right? Do we also need to know the conceptual question of choosing the correct indicator with certain pKa ...
by Vincent Leong 2B
Wed Dec 04, 2019 12:13 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 6
Views: 46

Re: Coordination Number

just count the number of things around the transition metal complex. Lone pairs count towards coordination numbers but there are never lone pairs around the transition metal complex (at least as far as I've seen). So your best bet will be to ask: "how many atoms are bonded to the transition met...
by Vincent Leong 2B
Wed Dec 04, 2019 12:10 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Rotations
Replies: 1
Views: 21

Re: Rotations

We look at the sigma or pi bonding. As Lavelle taught us, sigma bonds allow for rotation of the atoms wheras pi bonds restrict the atoms in place due to its lack of flexibility. So, if we see a molecule and notice that each atom has sigma bonds, because all bonds have sigma bonds present, then they ...
by Vincent Leong 2B
Wed Dec 04, 2019 12:07 am
Forum: Identifying Acidic & Basic Salts
Topic: Strategies
Replies: 1
Views: 27

Re: Strategies

Split the each of the two compounds of the reaction into it's ionic forms. ex. HCl + NaOH = H+Cl- + Na+Cl- then match charges together, + w/ - and vice versa ; when adding acids and bases together, you get a neutralization reaction so you know one of your end products is water (H2O) and a salt So HC...
by Vincent Leong 2B
Wed Dec 04, 2019 12:04 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: How do we write the equation to find the pH of a SA and WB
Replies: 1
Views: 19

How do we write the equation to find the pH of a SA and WB

For the interaction between HCl and CaO (a strong acid and weak base), what does its chemical equation look? Using the ice table, how can we find the pH of the solution?
by Vincent Leong 2B
Tue Dec 03, 2019 11:58 pm
Forum: Air Pollution & Acid Rain
Topic: What do we need to know?
Replies: 4
Views: 67

What do we need to know?

Do you think we'll be tested on sulfur and its relationship with the environment around us?
by Vincent Leong 2B
Mon Dec 02, 2019 3:04 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining the number of binding sites on a ligand
Replies: 2
Views: 29

Re: Determining the number of binding sites on a ligand

gferg21 wrote:I think we are supposed to memorize the list of ligand bonding sites for different atoms that Lavelle sent us or it will be difficult to determine using the Lewis structures.


where can this be found or what are they?
by Vincent Leong 2B
Sun Dec 01, 2019 5:23 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Content of the final
Replies: 10
Views: 149

Content of the final

Have we learned molecular orbital theory and bond order? Will it be covered on the final?
by Vincent Leong 2B
Sun Dec 01, 2019 4:12 pm
Forum: Naming
Topic: Roman numerals
Replies: 6
Views: 29

Re: Roman numerals

You determine the charge of the polyatomic ions within the coordination sphere and compare it to the charge of the overall coordination compound to find the charge of the transition metal. For example, [Fe(CN)6]^4-, we know CN has a -1 charge. So, 6(-1) + x = -4, solve for x (x being the charge of t...
by Vincent Leong 2B
Sat Nov 30, 2019 6:40 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining the number of binding sites on a ligand
Replies: 2
Views: 29

Determining the number of binding sites on a ligand

How can we know the maximum number of places on a ligand that can bind simultaneously to a metal center? I find it hard to find this number because I draw lewis structures but I still can't tell how many possible sites there are.
by Vincent Leong 2B
Sat Nov 30, 2019 6:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Final [ENDORSED]
Replies: 10
Views: 546

Re: Final [ENDORSED]

The "churro" session from lyndon's last year review session expired. If anyone knows someone who has the pdf, it would be greatly appreciated if they posted it here
by Vincent Leong 2B
Fri Nov 29, 2019 4:31 pm
Forum: Lewis Acids & Bases
Topic: Homework 6A 17
Replies: 2
Views: 25

Homework 6A 17

how do we go about determining whether each molecule is acidic or basic? Do we draw lewis structures or write out the equation w/ water or what?
by Vincent Leong 2B
Fri Nov 29, 2019 3:02 pm
Forum: Hybridization
Topic: Lyndons Worksheet Question 2
Replies: 1
Views: 44

Lyndons Worksheet Question 2

For the composition of each bond and hybridization of each lone pair of HCOOH, how do we know to include the energy level when writing the hybridization? For example, in the C-O bond, the notation is sigma(C2sp^2, Osp^3). Why does oxygen not have a 2 before its sp3 hybridization? Also, how can we te...
by Vincent Leong 2B
Thu Nov 28, 2019 4:51 pm
Forum: Bronsted Acids & Bases
Topic: Problem 6C17
Replies: 1
Views: 51

Re: Problem 6C17

BrO- is the conjugate base of a weak acid, so it must be relatively strong. So BrO- is the stronger base.

Due to the nitrogen with its lone pair being in morphine, it will always be considered a weak base.
by Vincent Leong 2B
Thu Nov 28, 2019 1:35 am
Forum: Bronsted Acids & Bases
Topic: J9
Replies: 3
Views: 69

Re: J9

Match the cations and anions of the diff compounds together. For example, a) KOH + HC2H3O2 --> K+ (OH-) + H+(C2H3O2-) = (H+)(OH-) + K+(C2H3O2-) (balance by coefficients)
by Vincent Leong 2B
Thu Nov 28, 2019 1:29 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Test Questions?
Replies: 2
Views: 43

Re: Test Questions?

We should know the coordination compounds and their biological functions (ex. cis platinum 3) because theyre significant in terms of chemistry and biology which he tends to focus on. I would also say to confidently explain how the specific coordination compounds he went over in class work chemically...
by Vincent Leong 2B
Thu Nov 28, 2019 1:26 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: Test 2 Hydrogen Bonding Question
Replies: 3
Views: 74

Re: Test 2 Hydrogen Bonding Question

So in terms of IMFs, more specifically H-bonds, we're taking into consideration the possible bonds between the H atom and the F, O, or N atom. When a compound has a F, O, or N atom, it is automatically a hydrogen bonding site (it's lone pairs of electrons each count as 1 site). Regardless if an H at...
by Vincent Leong 2B
Mon Nov 25, 2019 11:49 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Polarity
Replies: 10
Views: 68

Re: Determining Polarity

There is a diagram in the textbook that tells us which geometric shapes result in nonpolar compounds as long as the surrounding atoms are the same. It's really helpful. Drawing net dipoles also helps logically reason why a certain molecule is polar or nonpolar.
by Vincent Leong 2B
Mon Nov 25, 2019 11:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 6
Views: 54

Re: Test 2

The line is constant because if you made it a straight line increasing/decreasing, you would be saying that the number of electrons that are emitted are directly correlated to the frequency of the light. However, that's not the case (proven by the photoelectric effect). The number of electrons that ...
by Vincent Leong 2B
Mon Nov 25, 2019 11:43 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Multiple Bonding Sites
Replies: 1
Views: 19

Re: Multiple Bonding Sites

I think you would have to draw out the lewis structure of the ligand and find the lone pairs that exist in the compound. I'm not sure if theres a trick to just looking at a compounds molecular formula and finding the number of sites but it helps visually and logically to draw out the lewis structure...
by Vincent Leong 2B
Mon Nov 25, 2019 11:41 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: What type of concentrations can be part of the eq constant equation?
Replies: 1
Views: 17

What type of concentrations can be part of the eq constant equation?

Knowing that the Ka value = [H][A]/[HA] ---> are there certain compounds (s,l, or g) that can be included when calculating the equilibrium constant or can the concentrations of HA, A, and H only be aq solutions?
by Vincent Leong 2B
Fri Nov 22, 2019 10:37 pm
Forum: Biological Examples
Topic: Ringlike structures + chelating ligands
Replies: 2
Views: 15

Ringlike structures + chelating ligands

How do we know a certain ligand is chelating and what does that tell us?
by Vincent Leong 2B
Fri Nov 22, 2019 10:36 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Uncertainty about ligands
Replies: 2
Views: 24

Uncertainty about ligands

I'm still uncertain, what makes a certain molecule a ligand? How do these coordination compounds exist?
by Vincent Leong 2B
Fri Nov 22, 2019 10:32 pm
Forum: Naming
Topic: Naming Chlorine
Replies: 2
Views: 33

Re: Naming Chlorine

Amine should refer to the ammonia group (NH3)
by Vincent Leong 2B
Fri Nov 22, 2019 10:30 pm
Forum: Lewis Acids & Bases
Topic: Lewis v Bronsted v Arrhenius
Replies: 4
Views: 29

Re: Lewis v Bronsted v Arrhenius

They are all the same in the way, it's just the way you look at them. For example, Lewis acids are electron acceptors and that can be see with a molecule containing Boron (Lavelle showed this example in class). When putting HCl in water, H+ or a Hydrogen proton is being donated to the H2O molecule, ...
by Vincent Leong 2B
Fri Nov 22, 2019 10:26 pm
Forum: Biological Examples
Topic: Heme Complex
Replies: 5
Views: 42

Re: Heme Complex

As far as conceptually, I think we need to understand its function and how its molecular components have a role in playing in its biological function. And yes, I feel like Fe is always at the center of the heme complex because you can think of it like drawing lewis structures, the least electronegat...
by Vincent Leong 2B
Tue Nov 19, 2019 12:46 am
Forum: Student Social/Study Group
Topic: Test 2 Study Worksheets
Replies: 9
Views: 198

Re: Test 2 Study Worksheets

is there an answer key for this worksheet?
by Vincent Leong 2B
Mon Nov 18, 2019 11:15 am
Forum: Determining Molecular Shape (VSEPR)
Topic: What are the names of the geometries that we must know? [ENDORSED]
Replies: 3
Views: 37

What are the names of the geometries that we must know? [ENDORSED]

Is there a chart that lavelle goes by in terms of naming the molecular geometry? Just because I know of AX2E being v-shaped but apparently lavelle goes by classifying it as "bent" geometry. Is there a chart in the textbook he goes by?
by Vincent Leong 2B
Sun Nov 17, 2019 4:32 pm
Forum: Electronegativity
Topic: determining electronegativity
Replies: 4
Views: 35

Re: determining electronegativity

electronegativity is just the tendency for an atom to gain electrons. If you think of it logically, atoms on the further right side of the periodic table would want to get one electron in order to reach the most stable form (aka noble gas configuration)
by Vincent Leong 2B
Sun Nov 17, 2019 4:30 pm
Forum: Dipole Moments
Topic: London Forces
Replies: 4
Views: 26

Re: London Forces

yes, all molecules have london-dispersion forces; except in the cases where strong forces such as H-bonds exist, the h-bonds make the LDFs negligible in strength
by Vincent Leong 2B
Sun Nov 17, 2019 4:29 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: Is there a point where induced dipole induced dipole is stronger than ion ion?
Replies: 2
Views: 16

Re: Is there a point where induced dipole induced dipole is stronger than ion ion?

Ion-ion or electrostatic attractions are always stronger than LDFs no matter what. I dont think we'd ever get tested by a trick question where a large LDF is stronger than an electrostatic attraction.
by Vincent Leong 2B
Sun Nov 17, 2019 4:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2 Length
Replies: 9
Views: 68

Re: Test 2 Length

From what I heard, the tests are typically straight forward so I would say less conceptual questions and more testing you if you know the content being taught. For example, give the structure and bond angle of CH4
by Vincent Leong 2B
Sun Nov 17, 2019 4:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2 Length
Replies: 9
Views: 68

Re: Test 2 Length

From what I heard, the tests are typically straight forward so I would say less conceptual questions and more testing you if you know the content being taught. For example, give the structure and bond angle of CH4
by Vincent Leong 2B
Sun Nov 17, 2019 4:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR on the test or final
Replies: 4
Views: 33

Re: VSEPR on the test or final

study both the structure and bond angles of the vsepr models just to cover everything that could possibly on the test.
by Vincent Leong 2B
Sun Nov 17, 2019 4:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Bond Angles?
Replies: 3
Views: 22

Re: Determining Bond Angles?

for vsepr models, you have to memorize bond angles. only some structures can you logically derive the bond angle.
by Vincent Leong 2B
Mon Nov 11, 2019 1:39 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Bond Angles
Replies: 2
Views: 14

Re: Determining Bond Angles

Water's bond angle does correspond to a certain atomic symmetry.Aside from being able to tell bond angles from symmetry, there is no other method of knowing the bond angle. If there was, it is out of scope of this class.
by Vincent Leong 2B
Mon Nov 11, 2019 1:37 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs and Molecular Shape
Replies: 3
Views: 16

Re: Lone Pairs and Molecular Shape

To think about it in a molecular sense, it's less of the valence electrons distorting the atom's shape and more of the atom's respective effective nuclear charge or the amount of positive attraction the valence electrons experience from another atom's positive nucleus. The unequal attraction of elec...
by Vincent Leong 2B
Mon Nov 11, 2019 1:31 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Anions
Replies: 7
Views: 29

Re: Anions

Cations will always be the type of ions that will possess polarizing power whereas anions will possess polarizability.
by Vincent Leong 2B
Mon Nov 11, 2019 1:27 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Diatomic Molecules
Replies: 6
Views: 27

Re: Diatomic Molecules

Unless they are diatomic molecules or molecules of the same atom, a molecule will never be nonpolar because of differing electronegativities.
by Vincent Leong 2B
Mon Nov 11, 2019 1:24 am
Forum: Dipole Moments
Topic: Hydrogen bonds
Replies: 17
Views: 88

Re: Hydrogen bonds

H bonds can only form between F, O, and N atoms.
by Vincent Leong 2B
Tue Nov 05, 2019 4:43 pm
Forum: Quantum Numbers and The H-Atom
Topic: Midterm Content
Replies: 2
Views: 55

Midterm Content

Will we need to know the lyman/UV series, balmer, and infrared series and what energy level (n) value they start with? Will we also need to know the wavelength range of the UV region? or just the 400-700nm of the visible region?
by Vincent Leong 2B
Sun Nov 03, 2019 9:31 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 3
Views: 35

Drawing Lewis Structures

When drawing lewis structures, do we prioritize orienting valence e-s so the formal charge of the central atom is 0 or do we prioritize making the formal charge of the entire compound to 0 or close to 0? Also, is adding up the formal charges of each individual atom and comparing it to the charge of ...
by Vincent Leong 2B
Sun Nov 03, 2019 9:28 pm
Forum: Lewis Structures
Topic: Classifying Radicals
Replies: 1
Views: 16

Classifying Radicals

Is it safe to say that any complex compound with an odd number of valence electrons is a radical?
by Vincent Leong 2B
Sun Nov 03, 2019 9:28 pm
Forum: Lewis Structures
Topic: Classifying Radicals
Replies: 1
Views: 18

Classifying Radicals

Is it safe to say that any complex compound with an odd number of valence electrons is a radical?
by Vincent Leong 2B
Sun Nov 03, 2019 9:01 am
Forum: Dipole Moments
Topic: Content on the Midterm [ENDORSED]
Replies: 3
Views: 67

Content on the Midterm [ENDORSED]

Does the midterm cover all of Chapter 2 (Sections A-D) or just some parts of chapter 2?
by Vincent Leong 2B
Sat Nov 02, 2019 2:11 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: orbitals
Replies: 1
Views: 10

Re: orbitals

I believe the energy of the orbitals sort of has to do with the primary quantum number that each orbital begins with. The smallest principle quantum number for the s-orbital is 1, p-orbital is 2, d-orbital is 3, and f orbital is 4. It also has to do with their 3D configurations but I'm not too sure ...
by Vincent Leong 2B
Sat Nov 02, 2019 2:08 am
Forum: Resonance Structures
Topic: Delocalization
Replies: 4
Views: 34

Re: Delocalization

Hydrogren will never be the central atom. If it is sharing electrons through a covalent bond with another atom, hydrogen itself isn't delocalized but its electrons are.

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