Search found 50 matches

by Ashley Kim 3F
Sun Dec 08, 2019 2:55 am
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted
Replies: 7
Views: 181

Re: Lewis vs Bronsted

Some molecules may be Lewis acids but not Bronsted acids because they have the ability to accept a lone pair of electrons, but do not have a proton to donate.
by Ashley Kim 3F
Sun Dec 08, 2019 2:52 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Relationships between ka, pka, and ph
Replies: 7
Views: 150

Re: Relationships between ka, pka, and ph

Ka is the strength of an acid - a high Ka value means that the acid is strong, while a low Ka value indicates a weak acid. pKa is inverse - a high pKa value means that the acid is weak, while a low pKa value means that the acid is strong. pH is -log[H3O+] and is a measure of the concentration of hyd...
by Ashley Kim 3F
Sun Dec 08, 2019 2:50 am
Forum: Hybridization
Topic: Marshmallow Hybridization Problem
Replies: 3
Views: 123

Re: Marshmallow Hybridization Problem

The 2 is just to indicate the period that oxygen is found in and is not completely necessary when writing the hybridization. However, it can't hurt to put it on your answer !
by Ashley Kim 3F
Sun Dec 08, 2019 2:49 am
Forum: Administrative Questions and Class Announcements
Topic: Final tips
Replies: 19
Views: 291

Re: Final tips

I think that as it gets closer to the final, it is best to review the topics that you know you are weakest at and really try to understand the concepts at play.
by Ashley Kim 3F
Sun Dec 08, 2019 2:46 am
Forum: Lewis Acids & Bases
Topic: Lewis Structure
Replies: 2
Views: 85

Re: Lewis Structure

We can tell based off of the definition of a Lewis acid, which is a compound that can accept an electron pair, or a Lewis base, which is a compound that can donate an electron pair.
by Ashley Kim 3F
Fri Nov 29, 2019 5:56 pm
Forum: Bronsted Acids & Bases
Topic: Difference between Bronsted and Lewis
Replies: 2
Views: 32

Re: Difference between Bronsted and Lewis

The difference between Bronsted and Lewis acids and bases is in the way that they describe the actions of an acid and base. The Bronsted definition has to do with proton transfer while the Lewis definition has to do with electron lone pairs.
by Ashley Kim 3F
Fri Nov 29, 2019 5:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Studying for the Final [ENDORSED]
Replies: 11
Views: 263

Re: Studying for the Final [ENDORSED]

For the final, I would recommend looking over key concepts and making sure that you fully understand them, and then solve practice problems. Since we have taken two tests and a midterm, we know what types of problems will be asked and should prepare accordingly.
by Ashley Kim 3F
Fri Nov 29, 2019 5:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Metal Oxidation Number
Replies: 3
Views: 42

Re: Metal Oxidation Number

Main group elements have pretty consistent oxidation numbers, so they can be easily memorized. As for transition metals, I think that the best option would be to practice and memorize the oxidation numbers of the most common ones.
by Ashley Kim 3F
Fri Nov 29, 2019 5:50 pm
Forum: Naming
Topic: Amine vs Ammine?
Replies: 3
Views: 115

Re: Amine vs Ammine?

There is a difference between an amine and an ammine, and it's important to differentiate. An amine is a functional group from ammonia, while an ammine refers to a group of coordination compounds where ammonia is a ligand.
by Ashley Kim 3F
Fri Nov 29, 2019 5:47 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted vs. Lewis
Replies: 5
Views: 42

Re: Bronsted vs. Lewis

The difference is by definition, as Bronsted acids and bases are in terms of proton transfer while Lewis acids and bases are in terms of electron pairs.
by Ashley Kim 3F
Sun Nov 24, 2019 3:29 pm
Forum: Naming
Topic: Naming
Replies: 3
Views: 43

Re: Naming

I think a lot of the prefixes can be easily memorized by using the root! And for the other components of naming, you should practice and memorize the rules too.
by Ashley Kim 3F
Sun Nov 24, 2019 3:28 pm
Forum: Sigma & Pi Bonds
Topic: Sigma & Pi Bonds
Replies: 9
Views: 121

Re: Sigma & Pi Bonds

There is a greater overlap between atomic orbitals in sigma bonds, meaning that it is more likely that more electrons are present in overlap.
by Ashley Kim 3F
Sun Nov 24, 2019 12:40 am
Forum: Naming
Topic: Naming Order
Replies: 6
Views: 78

Re: Naming Order

I don't think it necessarily matters how the formula is arranged as long as the naming is done alphabetically.
by Ashley Kim 3F
Sun Nov 24, 2019 12:38 am
Forum: General Science Questions
Topic: Sig Figs
Replies: 7
Views: 129

Re: Sig Figs

It can't hurt to always use the correct amount of sig figs when indicating answers on an exam!
by Ashley Kim 3F
Fri Nov 22, 2019 11:17 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 13
Views: 147

Re: Lone pairs

Lone pairs on the central atom account for the electronic arrangement of a molecule and sometimes for the shape of the molecule.
by Ashley Kim 3F
Fri Nov 15, 2019 11:24 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: induced dipoles
Replies: 5
Views: 62

Re: induced dipoles

Induced dipoles occur when temporary and fluctuating electron densities create a net favorable attractive force. Dipole-induced dipoles usually occur between a polar and nonpolar molecule.
by Ashley Kim 3F
Fri Nov 15, 2019 11:18 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework Problem 2E.7
Replies: 3
Views: 42

Re: Homework Problem 2E.7

is writing "less than 109.5" an exceptable answer, or do we have to give a specific number? I'm pretty sure than writing "less than 109.5" is an acceptable answer since we haven't gone much further than that in terms of bond angles. As of now, we don't know how to calculate the ...
by Ashley Kim 3F
Fri Nov 15, 2019 11:17 am
Forum: Lewis Structures
Topic: Ground-State Electron Configuration
Replies: 5
Views: 58

Re: Ground-State Electron Configuration

Electron configurations, unless otherwise specified, refer to the ground-state electron configuration of lowest energy. If the electrons were excited, it would specify in the problem.
by Ashley Kim 3F
Fri Nov 15, 2019 11:14 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 11
Views: 109

Re: Test 2

I'm reading over the textbook sections relevant to the topics tested on the midterm to get a grasp of the conceptual ideas, and then I'm going to do the homework problems. Looking over lecture notes and solving problems is probably the way to go!
by Ashley Kim 3F
Fri Nov 15, 2019 11:13 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 6
Views: 77

Re: Bond Angles

I agree with the above posts - as you practice VSEPR related problems and get more exposure to relationships between the shapes and angles, I am sure that you will find yourself having memorized the corresponding angles!
by Ashley Kim 3F
Tue Nov 12, 2019 6:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Studying
Replies: 14
Views: 263

Re: Final Studying

Based on the midterm, I would review and practice concepts that I am less confident in to reinforce those topics, and as for material that was covered after the midterm, I would make sure that I can fully grasp the conceptual base of the topic and can apply it to practice problems.
by Ashley Kim 3F
Tue Nov 12, 2019 6:08 pm
Forum: Quantum Numbers and The H-Atom
Topic: n, l ,ml, ms
Replies: 13
Views: 485

Re: n, l ,ml, ms

As everyone above mentioned, the only two possible values for ms are +½ and -½. In a quiz or test, the spin of the electron will most likely be easy to determine given the wording or information provided in the question, so I don't think you need to worry about it too much!
by Ashley Kim 3F
Tue Nov 12, 2019 6:06 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 in Biological Systems
Replies: 2
Views: 31

Re: Hydrogen Bonding in Biological Systems

Hydrogen bonding is prevalent in biological systems because of its strength despite the noncovalent interaction it has in many organic molecules. As the comment above mentions, it helps stabilize biological systems!
by Ashley Kim 3F
Tue Nov 12, 2019 6:02 pm
Forum: DeBroglie Equation
Topic: When to Use
Replies: 8
Views: 188

Re: When to Use

De Broglie's equation essentially calculates the wavelength using a particle's mass and velocity, so given any one of those values (knowing that the particle has mass), you should use the De Broglie equation to solve for the unknown value.
by Ashley Kim 3F
Tue Nov 12, 2019 5:59 pm
Forum: Octet Exceptions
Topic: expanded octet
Replies: 7
Views: 238

Re: expanded octet

Elements with orbitals in the d-block can have expanded octets. However, although P, S, and Cl do not have orbitals in the d-block, they are exceptions to the octet rule and can also hold more electrons than the standard octet.
by Ashley Kim 3F
Sun Nov 03, 2019 2:10 pm
Forum: Bond Lengths & Energies
Topic: dissociation energy
Replies: 7
Views: 92

Re: dissociation energy

Dissociation energy is always positive because you are inputting energy into the system, not taking it out.
by Ashley Kim 3F
Sun Nov 03, 2019 2:09 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: electron configuration
Replies: 4
Views: 62

Re: electron configuration

You would remove electrons from the 4s orbital because it is of higher energy than the 3d orbital.
by Ashley Kim 3F
Sun Nov 03, 2019 2:08 pm
Forum: Bond Lengths & Energies
Topic: Test?
Replies: 8
Views: 187

Re: Test?

I don't recall going over how to calculate bond length during class, so I'm pretty sure we don't need to know how to do that for the midterm.
by Ashley Kim 3F
Sun Nov 03, 2019 2:07 pm
Forum: Electronegativity
Topic: Ionic or covalent?
Replies: 17
Views: 211

Re: Ionic or covalent?

Usually, the elements at either end of the periodic table, when bonded together, form ionic bonds because it is easier for the electrons to be transferred due to the number of valence electrons they have. On the other hand, covalent bonds form between elements that cannot transfer electrons but inst...
by Ashley Kim 3F
Sun Nov 03, 2019 2:03 pm
Forum: Lewis Structures
Topic: Resonance Hybrid
Replies: 2
Views: 28

Re: Resonance Hybrid

I think that to be safe, we should understand the concept of a resonance hybrid and how to draw one, just in case a question comes up on the midterm. But I wouldn't stress about it too much!
by Ashley Kim 3F
Sat Oct 26, 2019 9:24 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Notation
Replies: 5
Views: 47

Re: Electron Configuration Notation

Although the first method of writing the electron configuration is not wrong, I think that Dr. Lavelle mentioned that he would like for us to notate it the second way, unlike how we did in high school.
by Ashley Kim 3F
Sat Oct 26, 2019 9:22 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ionization Energy
Replies: 4
Views: 43

Re: Ionization Energy

It is always more difficult to remove the second electron because the net positive charge exerted by the nucleus affects it greater than the electrons in the outer shells. As you remove more electrons, the more energy it takes to remove each one.
by Ashley Kim 3F
Sat Oct 26, 2019 9:20 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Bonds
Replies: 4
Views: 44

Re: Ionic and Covalent Bonds

I agree with all the statements made above - ionic bonds occur between a nonmetal and a metal and the valence electrons are transferred between the two atoms. On the other hand, covalent bonds occur when two nonmetal atoms share electrons pairs.
by Ashley Kim 3F
Sat Oct 26, 2019 9:18 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 6
Views: 62

Re: Resonance

A compound with resonance is stable than one that does not have resonance because it is a hybrid of individual resonance structures and does not shift between them.
by Ashley Kim 3F
Sat Oct 19, 2019 8:59 pm
Forum: Properties of Electrons
Topic: mass of electron, proton, neutron
Replies: 7
Views: 99

Re: mass of electron, proton, neutron

I am pretty sure that these values are on the equation sheet because they are not particularly nice numbers to memorize!
by Ashley Kim 3F
Sat Oct 19, 2019 8:57 pm
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 358

Re: Midterm

Unless Dr. Lavelle states so, I do not think that there will be an official practice midterm posted. However, the test bank is a useful resource to see what types of problems will be on the homework. I also think that the types of questions we see on the homework should be indicative of the types of...
by Ashley Kim 3F
Sat Oct 19, 2019 8:54 pm
Forum: Properties of Electrons
Topic: Electron structures
Replies: 2
Views: 42

Re: Electron structures

I think that it does matter which orbital you put the 4th arrow in to indicate to the grader that you understand the concept of orbitals. One orbital must be filled before the next can be filled (this being after there is one arrow in each orbital), so it would make sense to put the 4th arrow in the...
by Ashley Kim 3F
Sat Oct 19, 2019 8:51 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Tips for the Midterm
Replies: 10
Views: 121

Re: Tips for the Midterm

Some study tips that I find useful are to first thoroughly understand the conceptual aspects of the topics we cover in class, and then do practice problems to reinforce the application of those concepts. Because the practice problems that we have seen assigned on the homework so far are mostly calcu...
by Ashley Kim 3F
Sat Oct 19, 2019 3:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 7
Views: 82

Re: Writing Electron Configurations

I know that in high school, we never wrote the x, y, z, in the electron configurations, but I think I remember that during lecture on Friday, Dr. Lavelle mentioned that he wouldn't mind if we wrote out the x, y, z to show that we understand the meaning of it.
by Ashley Kim 3F
Thu Oct 10, 2019 1:23 pm
Forum: Properties of Light
Topic: Atom's transition
Replies: 3
Views: 42

Re: Atom's transition

Yes, I believe that if there is a greater energy difference (eg. difference between energy levels increases), the transition between energy levels is larger, meaning that more energy is absorbed or emitted. Therefore, since the photon that is emitted has the same energy as the energy difference, it ...
by Ashley Kim 3F
Wed Oct 09, 2019 4:26 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 4
Views: 75

Re: Speed of Light

I would think so, so maybe we assume that the situations described in problems involving the speed of light occur in a vacuum?
by Ashley Kim 3F
Wed Oct 09, 2019 4:21 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G21 [ENDORSED]
Replies: 2
Views: 109

Re: Fundamentals G21 [ENDORSED]

To find the final concentration of potassium ions and sulfide ions, you have to use stoichiometry to find the total moles of K+ and S2- ions. Add the number of moles of K+ ions in .500g KCl, K2S, and K3PO4, respectively and divide the total moles K+ by .5L H2O to get the final concentration of potas...
by Ashley Kim 3F
Wed Oct 09, 2019 4:12 pm
Forum: Significant Figures
Topic: %Mass Composition
Replies: 12
Views: 323

Re: %Mass Composition

The number of sig figs depends on the lowest sig fig of the numbers give in the problem. However, if the problem does not mention any numbers that you can base your sig figs on, I think it's safe to have at least 4 sig figs.
by Ashley Kim 3F
Wed Oct 09, 2019 4:11 pm
Forum: Quantum Numbers and The H-Atom
Topic: Atomic Spectra
Replies: 5
Views: 59

Re: Atomic Spectra

Dr. Lavelle mentioned that the emission and absorption must be balanced, so the amount of energy that is emitted is equal to the amount of energy that is absorbed.
by Ashley Kim 3F
Wed Oct 09, 2019 4:03 pm
Forum: Properties of Electrons
Topic: Energy Levels
Replies: 8
Views: 70

Re: Energy Levels

When an electron drops two levels, it is not that two photons are emitted, but that the one photon that is emitted has more energy that if the electron only dropped one level.
by Ashley Kim 3F
Fri Oct 04, 2019 9:59 pm
Forum: Empirical & Molecular Formulas
Topic: Homework Problem L39
Replies: 2
Views: 127

Re: Homework Problem L39

I remember my TA telling us that it is not completely necessary to be able to name all the compounds and oxides and such, but that knowing the most common few is recommended and will be beneficial.
by Ashley Kim 3F
Wed Oct 02, 2019 11:08 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Question
Replies: 4
Views: 42

Re: Limiting Reactant Question

In conjunction with what everyone else said, in this situation, there is no limiting reactant. A practical way to think about this is in terms of baking - if the recipe calls for a certain amount of an ingredient and you have the ingredients in the required amounts, you will be able to create the ba...
by Ashley Kim 3F
Wed Oct 02, 2019 11:01 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding for Formulas
Replies: 8
Views: 145

Re: Rounding for Formulas

In regards to the post right above me, I think that the safest bet is to use the convention that we probably learned in high school to not round until you get to the final answer. At that point, we should take into account the smallest number of sig figs in the given problem and round accordingly. T...
by Ashley Kim 3F
Tue Oct 01, 2019 1:10 pm
Forum: Limiting Reactant Calculations
Topic: Determining Limiting Reactant by Mole or Mass
Replies: 8
Views: 123

Re: Determining Limiting Reactant by Mole or Mass

I agree that there are multiple ways to go about chemistry problems, but from my experience, what the limiting reactant is is clearer when you are comparing moles. Only looking at the given masses of molecules will not always tell you the limiting reactant because you need to take into account the m...
by Ashley Kim 3F
Tue Oct 01, 2019 12:44 pm
Forum: Empirical & Molecular Formulas
Topic: Mass Percent Composition
Replies: 5
Views: 102

Re: Mass Percent Composition

I think that imagining that you have 100g of a molecule when figuring out empirical and molecular formulas is just a useful tip for when the numbers are not particularly pretty or easy to work with, but not a necessary component. However, you can not go directly to moles from the given grams of diff...

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