Search found 65 matches

by David Jen 1J
Sun Jan 17, 2021 6:15 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure Rule
Replies: 29
Views: 183

Re: Pressure Rule

Only count moles of gas.
by David Jen 1J
Sun Jan 17, 2021 2:49 am
Forum: General Science Questions
Topic: Conjugate Acids and Bases
Replies: 4
Views: 19

Re: Conjugate Acids and Bases

I think it highlights the reversible action of a acid base reaction. In cases where the acid/base aren't strong, the conjugates could potentially play a role in regulating environments (pH), such as bicarbonate in the ocean and our blood.
by David Jen 1J
Sun Jan 17, 2021 2:46 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Kelvin or Celsius?
Replies: 55
Views: 1295

Re: Kelvin or Celsius?

use kelvin.
by David Jen 1J
Sun Jan 17, 2021 2:39 am
Forum: General Science Questions
Topic: Significant Figures and Rounding
Replies: 9
Views: 33

Re: Significant Figures and Rounding

The good thing is, there is essentially no homework graded for this class except sapling, and you have infinite attempts per question, so I wouldn't worry about sig figs in that aspect.
by David Jen 1J
Sun Jan 17, 2021 2:37 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ka vs kb
Replies: 20
Views: 55

Re: ka vs kb

Yes, Ka is for acids and Kb is for bases.
by David Jen 1J
Sun Jan 17, 2021 2:31 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O as a Gas
Replies: 53
Views: 372

Re: H2O as a Gas

We include gases, except for inert gases.
by David Jen 1J
Sun Jan 17, 2021 2:29 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: q vs k
Replies: 62
Views: 161

Re: q vs k

Q calculates the same way as K, but Q calculates at concentrations that aren't equilibrium.
by David Jen 1J
Sun Jan 10, 2021 4:09 am
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 91
Views: 233

Re: Study Habits

I heard of step up sessions but I don't know what happens there. Could someone fill me in on those? I'm kind of interested in attending one this quarter.
by David Jen 1J
Sun Jan 10, 2021 4:04 am
Forum: Ideal Gases
Topic: Advice on how to navigate Chem Community
Replies: 17
Views: 67

Re: Advice on how to navigate Chem Community

It can feel a bit overwhelming, something that has helped me was the active topic section you can find under quick links, it gave me a way to find relevant topics that I can reply to!
by David Jen 1J
Sun Jan 10, 2021 4:00 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Definition of an Inert Gas
Replies: 6
Views: 23

Re: Definition of an Inert Gas

An inert gas is a element that doesn't react to other elements because it's valence shell is filled. Often it is the noble gases because the valence shell is filled.
by David Jen 1J
Sun Jan 10, 2021 3:48 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Counting Moles
Replies: 11
Views: 44

Re: Counting Moles

Only gases are counted!
by David Jen 1J
Sun Jan 10, 2021 3:40 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q and K
Replies: 13
Views: 31

Re: Q and K

How would you be able to calculate K if you're only given concentrations for Q? They would typically give K to you right?
by David Jen 1J
Sat Dec 12, 2020 3:34 pm
Forum: Naming
Topic: Bis, Tris, Tetrakis
Replies: 4
Views: 46

Bis, Tris, Tetrakis

If a molecule has the prefix bis, tris, tetrakis, etc, would that prefix be counted when looking to name the coordination compound? I'm asking because, for question 9c.3, part d named the compound: sodium bisoxalato(diaqua)ferrate(III), when if following the rules, aqua would be first instead of oxa...
by David Jen 1J
Sat Dec 12, 2020 2:55 pm
Forum: Calculating the pH of Salt Solutions
Topic: Textbook Question 6D.11
Replies: 2
Views: 33

Re: Textbook Question 6D.11

Me too. Also, does Al3+ make it's surrounding solution acidic because it can give off protons or is it accepting electrons?
by David Jen 1J
Fri Dec 11, 2020 1:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Ligands
Replies: 2
Views: 43

Chelating Ligands

Can trans- orientated ligands be bidentate? More specifically, C2C04?
by David Jen 1J
Thu Dec 10, 2020 11:39 am
Forum: Conjugate Acids & Bases
Topic: Can strong acids become conjugate bases?
Replies: 3
Views: 52

Can strong acids become conjugate bases?

If the pH is low enough, can a strong acid become a conjugate base?
by David Jen 1J
Thu Dec 10, 2020 11:28 am
Forum: Amphoteric Compounds
Topic: Strong Acid and Amphoteric?
Replies: 3
Views: 39

Strong Acid and Amphoteric?

When learning about Amphoteric molecules, I noticed that the strong acid H2S04, when deprotonated, has a similar structure as other Amphoteric molecules. However, can it be considered a amphoteric molecule if it is a strong acid?
by David Jen 1J
Sun Dec 06, 2020 10:07 pm
Forum: Naming
Topic: Monodentates and Polydentates
Replies: 8
Views: 65

Re: Monodentates and Polydentates

So is dentate synonymous with ligand?
by David Jen 1J
Sun Dec 06, 2020 10:04 pm
Forum: Naming
Topic: "(en)" Sapling
Replies: 19
Views: 105

Re: "(en)" Sapling

(en) is short for ethylenediamine. I'm pretty sure there are more compounds that have similar naming nature so make sure to read about those ones too as it might be on the test!
by David Jen 1J
Sat Dec 05, 2020 9:07 pm
Forum: Biological Examples
Topic: Hemoglobin vs. Myoglobin
Replies: 29
Views: 215

Re: Hemoglobin vs. Myoglobin

Hemoglobin is 4 myoglobin put together. As a result, hemoglobin can carry more oxygen at one time.
by David Jen 1J
Sat Dec 05, 2020 8:54 pm
Forum: Amphoteric Compounds
Topic: How to know if a molecule is amphoteric
Replies: 9
Views: 97

Re: How to know if a molecule is amphoteric

I think amphoteric compounds tend to typically have polar bond when containing a H. As a result, there is a H to be donated. If it is donated, there is potential for it to re-accept the H as well.
by David Jen 1J
Sat Dec 05, 2020 8:44 pm
Forum: Lewis Acids & Bases
Topic: Bronsted vs. Lewis bases
Replies: 11
Views: 70

Re: Bronsted vs. Lewis bases

Lewis bases donate electrons, Bronstead bases accept protons. Essentially they are the same thing.
by David Jen 1J
Sun Nov 29, 2020 6:45 pm
Forum: Administrative Questions and Class Announcements
Topic: 14B Enrollment [ENDORSED]
Replies: 26
Views: 1332

Re: 14B Enrollment [ENDORSED]

I am currently waitlisted for the winter quarter and according to Prof. Lavelle, I'll be able to get in. But I'm wondering how PTE and enrollment works. Could someone explain it? Thanks.
by David Jen 1J
Sun Nov 29, 2020 6:31 pm
Forum: Lewis Structures
Topic: Octet rule
Replies: 12
Views: 114

Re: Octet rule

Hydrogen is also an exception to the octet rule!
by David Jen 1J
Sun Nov 29, 2020 6:28 pm
Forum: Dipole Moments
Topic: Tetrahedral Atoms and Dipole Moments
Replies: 7
Views: 45

Re: Tetrahedral Atoms and Dipole Moments

Dipole moments can only be cancelled out on a Tetrahedral Atom when it is four of the same elements bonded to a central element. (CCl4)
by David Jen 1J
Sun Nov 29, 2020 6:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: molecule shape polarity
Replies: 5
Views: 40

Re: molecule shape polarity

It has to do with dipole moments. A molecule could have all polar covalent bonds and still be nonpolar due to it's shape because the bonds are directly 180 degrees away from each other. H20, because it is bent, not linear, has dipoles that aren't cancelled out. BeCl2, on the other hand, also has pol...
by David Jen 1J
Sun Nov 29, 2020 6:20 pm
Forum: Hybridization
Topic: Sapling #18
Replies: 10
Views: 98

Re: Sapling #18

I also was very confused with this problem, is there any way it has to do with the number of double bonds as well?
by David Jen 1J
Sun Nov 29, 2020 6:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Knowing VESPR for final
Replies: 5
Views: 40

Re: Knowing VESPR for final

I'm pretty sure we need to memorize all the ones Prof. Lavelle goes over.
by David Jen 1J
Sun Nov 22, 2020 6:23 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 33
Views: 200

Re: Covalent Character

To determine covalent character in ionic bonds, you find the DEN of the elements. The lower the DEN, the more covalent it is.
by David Jen 1J
Sun Nov 22, 2020 6:22 pm
Forum: Octet Exceptions
Topic: Expanded Octets
Replies: 11
Views: 85

Re: Expanded Octets

Out of curiosity, does anyone know if there is a certain max number of electrons in a expanded octet?
by David Jen 1J
Sun Nov 22, 2020 6:16 pm
Forum: Lewis Structures
Topic: Electron Density
Replies: 14
Views: 115

Re: Electron Density

Hi. Electron density is basically where a certain electron could be at any given point.
by David Jen 1J
Tue Nov 17, 2020 6:26 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 3
Views: 56

Midterm 2

Prof. Lavelle said in his class website that midterm 2 is up to chemical bonds, does that mean vsper model are not part of the midterm? And if anyone knows, where in the textbook does content go up to? Thanks.
by David Jen 1J
Sat Nov 14, 2020 9:11 pm
Forum: Resonance Structures
Topic: Formal Charge influence on Resonance Structure
Replies: 4
Views: 18

Re: Formal Charge influence on Resonance Structure

And if so, does overall formal charge sum also always indicate the overall charge of the molecule?
by David Jen 1J
Sat Nov 14, 2020 9:10 pm
Forum: Resonance Structures
Topic: Formal Charge influence on Resonance Structure
Replies: 4
Views: 18

Formal Charge influence on Resonance Structure

Just to clarify, resonance structures are most stable/tend to favor positions where formal charge on each atom is zero right?
by David Jen 1J
Sat Nov 14, 2020 8:54 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Formula
Replies: 4
Views: 40

Re: Formal Charge Formula

In this equation, the lone stands for all of the free/unbonded electrons. Don't think of it as lone pairs as you might count two electrons as one pair and plug 1 in the equation. Think of it as the individual electrons, so in this example it would be 2 electrons and you would use 2 in the FC equati...
by David Jen 1J
Sat Nov 14, 2020 8:52 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 7
Views: 89

Re: Radicals

Is there a way to predict which element in an atom will have the radical? this came up in textbook problem 2C.5. The radical went with Cl rather than O, and I can't explain why except for that Cl has an odd number of valence electrons to start with. Hi! I believe that the placement of the lone elec...
by David Jen 1J
Sat Nov 14, 2020 8:46 pm
Forum: Ionic & Covalent Bonds
Topic: Electronegativity
Replies: 18
Views: 104

Re: Electronegativity

To calculate electronegativity, there is a specific periodic table that shows the electronegativity of every element. However, I think when not asked to detemine the specific DEN, one can base it off of periodic trends (ie far left is more electromotive than far right) and determine an idea of elect...
by David Jen 1J
Sat Nov 14, 2020 8:44 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Formula
Replies: 4
Views: 40

Formal Charge Formula

In the formal charge formula, F= V- (Lone - Bonds/2), does lone stand for lone pairs and unbonded electrons or just lone pairs.
by David Jen 1J
Sun Nov 08, 2020 2:13 pm
Forum: Lewis Structures
Topic: Lone Pairs Question
Replies: 22
Views: 119

Re: Lone Pairs Question

Lone pair electrons are pairs that have not been bonded and naturally belong to said atom.
by David Jen 1J
Sun Nov 08, 2020 2:08 pm
Forum: Octet Exceptions
Topic: Octet rule
Replies: 9
Views: 64

Re: Octet rule

The octet rule is the concept that every atom wants to fill it's valence shells to achieve stability and lots of atoms do it by filling their shells, which can contain up to 8, with some special exceptions. As a result, the octet rule is a baseline for creating the structure of compounds by trying t...
by David Jen 1J
Fri Nov 06, 2020 3:03 pm
Forum: Lewis Structures
Topic: Lewis base
Replies: 3
Views: 29

Re: Lewis base

Lewis base is just something that donates electrons. I wouldn't necessarily say all negative charges mean it's a lewis base but it's a good way to start off if asked to find a lewis base.
by David Jen 1J
Fri Nov 06, 2020 2:54 pm
Forum: Ionic & Covalent Bonds
Topic: Polarity
Replies: 9
Views: 88

Re: Polarity

Polarity means that there is an unequal charge, an unequal distribution of a shared electron. Thus a polar covalent bond has polarity because of an unequally shared electron.
by David Jen 1J
Fri Nov 06, 2020 2:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm grades
Replies: 19
Views: 204

Re: Midterm grades

The grades are out!
by David Jen 1J
Sun Nov 01, 2020 11:27 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: d orbitals
Replies: 17
Views: 97

Re: d orbitals

5 d orbitals means that there are 5 orbitals in the d orbital. Each orbital holds 2 electrons.
by David Jen 1J
Sun Nov 01, 2020 11:24 pm
Forum: Quantum Numbers and The H-Atom
Topic: Ionization Energy Trend
Replies: 6
Views: 54

Re: Ionization Energy Trend

This is because the lower the molecule on a table, the bigger it is, thus it is easier to remove an electron from it's outer shell compared to a smaller molecule because the level of attraction is lower.
by David Jen 1J
Sun Nov 01, 2020 11:22 pm
Forum: DeBroglie Equation
Topic: Avogadro's Number
Replies: 21
Views: 129

Re: Avogadro's Number

Avogadro's number represents the number of atoms in one mole. Thus, we should use it whenever a question asks for something regarding atoms.
by David Jen 1J
Sun Nov 01, 2020 11:21 pm
Forum: Properties of Light
Topic: Which model of light is atomic spectroscopy?
Replies: 8
Views: 95

Re: Which model of light is atomic spectroscopy?

The particle model is supported by atomic spectroscopy.
by David Jen 1J
Thu Oct 29, 2020 10:27 am
Forum: *Particle in a Box
Topic: Midterm 1
Replies: 16
Views: 258

Re: Midterm 1

So we don't need to study 1.D?
by David Jen 1J
Sun Oct 25, 2020 2:45 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Advice for studying
Replies: 92
Views: 2030

Re: Advice for studying

I like to do practice problems and read the textbook. Practice problems is where I mostly retain information from.
by David Jen 1J
Sun Oct 25, 2020 2:42 am
Forum: *Shrodinger Equation
Topic: Schrodinger on MT
Replies: 7
Views: 83

Schrodinger on MT

Does anyone know if there will be Schrodinger related questions on MT1?
by David Jen 1J
Sun Oct 25, 2020 2:41 am
Forum: Molarity, Solutions, Dilutions
Topic: What does mmol stand for?
Replies: 33
Views: 329

Re: What does mmol stand for?

Hi, mmol is a millimol, which is 1/1000th of a mol.
by David Jen 1J
Sun Oct 25, 2020 2:40 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Rounding when the last digit is 5
Replies: 6
Views: 78

Re: Rounding when the last digit is 5

For general problems, it is round up. But remember that when dealing with mols in empirical formula problems, we multiply to the nearest whole number.
by David Jen 1J
Sun Oct 25, 2020 2:36 am
Forum: Properties of Light
Topic: Constants
Replies: 21
Views: 106

Re: Constants

I like to use whatever is on the formula sheet to like 4 decimals.
by David Jen 1J
Sat Oct 17, 2020 2:21 am
Forum: Properties of Light
Topic: Energy Levels
Replies: 11
Views: 92

Re: Energy Levels

Hey Chesca, electrons don't technically jump/skip levels, they just have enough energy to go all the way to N=4. That means they'd have to have enough energy to make it through n=2 and n=3 before it could make it to n=4
by David Jen 1J
Fri Oct 16, 2020 8:15 pm
Forum: Properties of Electrons
Topic: Spectral Lines
Replies: 7
Views: 90

Re: Spectral Lines

I'm also a bit confused on this topic. Do we just take the difference between n-levels? For example, if an electron starts at the n=6 level and falls to the n=1 level, did it "pass" 5 spectral lines? And if an electron starts at the n=4 level and drops to the n=2 level, did it "pass&...
by David Jen 1J
Fri Oct 16, 2020 8:11 pm
Forum: Properties of Light
Topic: Wave particle duality
Replies: 4
Views: 20

Re: Wave particle duality

During Friday's lecture, Dr. Lavelle shows us the experiment where they shine light through an area with openings and light enters and appears where there isn't an opening. If the light was not a wave, the light would just shine straight instead of bending. Because the light was refracted, we are ab...
by David Jen 1J
Fri Oct 16, 2020 8:07 pm
Forum: Properties of Light
Topic: Does light lose energy the farther it travels?
Replies: 8
Views: 93

Re: Does light lose energy the farther it travels?

I searched it up and yes light does lose energy the further it travels. But for it to lose energy, it would have to travel super far. That's why we can see stars but aren't super bright.
by David Jen 1J
Fri Oct 16, 2020 8:05 pm
Forum: Properties of Light
Topic: Energy Levels
Replies: 11
Views: 92

Energy Levels

In equations such as E=hR/n^2, Dr. Lavelle explains n as energy levels. However, I don't really understand what energy levels are. Could someone explain it?
by David Jen 1J
Mon Oct 12, 2020 2:49 pm
Forum: Properties of Light
Topic: Quanta and Photons
Replies: 19
Views: 172

Re: Quanta and Photons

What exactly does it mean that the variables in quantum mechanic equations are "quantized or discrete?" Hi, what this means is that instead of viewing light as one thing, it is viewed as a stream of photons, where each photon is one discrete unit. It is basically looking at every day thin...
by David Jen 1J
Thu Oct 08, 2020 10:42 pm
Forum: Empirical & Molecular Formulas
Topic: Calculation Errors for Empirical Formulas
Replies: 10
Views: 67

Re: Calculation Errors for Empirical Formulas

2.8 is close enough to 3 to round up, The only time I wouldn't round up if is it is super close to .75
by David Jen 1J
Thu Oct 08, 2020 10:37 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical and Molecular Formula
Replies: 17
Views: 124

Re: Empirical and Molecular Formula

The molecular formula can be the same as the empirical formula.
by David Jen 1J
Thu Oct 08, 2020 10:29 pm
Forum: Significant Figures
Topic: Integers in calculations
Replies: 6
Views: 46

Re: Integers in calculations

I'm a little bit confused about integers too. For example, for 300, wouldn't it be like 3 * 10^2 and only have one sig fig? For it to count as 3 sig figs, it has to be written as 300. or 3.00 * 10^2 right? When can we assume that an integer has infinite number of sig figs? Hello! Every question you...
by David Jen 1J
Thu Oct 08, 2020 10:17 pm
Forum: Significant Figures
Topic: Sig Figs for Molar Mass
Replies: 14
Views: 115

Re: Sig Figs for Molar Mass

I use 4 sig figs most of the time
by David Jen 1J
Thu Oct 08, 2020 10:14 pm
Forum: Significant Figures
Topic: Molar Mass Sig Figs
Replies: 9
Views: 81

Re: Molar Mass Sig Figs

I also use 4 sig figs.

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