Search found 61 matches

by AKhanna_3H
Sat Jan 18, 2020 11:02 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tips for Test
Replies: 16
Views: 47

Re: Tips for Test

Last quarter for 14A with Lavelle, I did all the practice problems on the syllabus for the topics we would be tested on and I found that to be very helpful!
by AKhanna_3H
Sat Jan 18, 2020 11:00 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in Pressure
Replies: 5
Views: 23

Re: Change in Pressure

If more reactants are added (increasing the number of moles), the reaction will "shift right" meaning more products will be formed to offset that change. Now that there are more reactants available, more products must form to keep the reaction in equilibrium. If reactants are removed (decr...
by AKhanna_3H
Sat Jan 18, 2020 10:57 am
Forum: Administrative Questions and Class Announcements
Topic: Study Guide Test One
Replies: 17
Views: 54

Re: Study Guide Test One

There's no study guide, but for 14A with Dr. Lavelle I found it was very helpful to do all the practice problems on the syllabus for the sections we would be tested on. For test 1 I believe those are the first two sections.
by AKhanna_3H
Sat Jan 18, 2020 10:55 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between K and Q?
Replies: 9
Views: 21

Re: Difference between K and Q?

Q and K are both measured by the ratio of products over reactants, but K represents that ratio at equilibrium while Q can represent that ratio at any point in the reaction.
by AKhanna_3H
Sat Jan 18, 2020 10:54 am
Forum: Administrative Questions and Class Announcements
Topic: How was my Friday class/lecture?
Replies: 3
Views: 14

Re: How was my Friday class/lecture?

I really appreciated that there were a lot of examples and we went through each in detail.
by AKhanna_3H
Sun Jan 12, 2020 3:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 1 date
Replies: 4
Views: 14

Re: Test 1 date

During your week 3 discussion
by AKhanna_3H
Sun Jan 12, 2020 3:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: What is this?
Replies: 21
Views: 99

Re: What is this?

Le Chatelier's Principle explains how chemical reactions shift to minimize the effects of a change. For example, if more reactants are added, the reaction will shift "right" and more product is formed. If reactants are removed, the reaction will shift "left" and less products wil...
by AKhanna_3H
Sun Jan 12, 2020 3:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use Kc vs Kp
Replies: 7
Views: 24

Re: When to use Kc vs Kp

Kc refers to concentrations and Kp refers to pressure, so (aq) would correlate to Kc and (g) to Kp
by AKhanna_3H
Sun Jan 12, 2020 3:40 pm
Forum: Administrative Questions and Class Announcements
Topic: 14A Final Pickup
Replies: 5
Views: 28

14A Final Pickup

What room can we pick up our 14A finals from? And can we start getting them this week or next week?
by AKhanna_3H
Tue Jan 07, 2020 3:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework 1
Replies: 18
Views: 104

Homework 1

When is the first homework assignment due? I know they are usually due in discussion sections but is that also true for week 1?
by AKhanna_3H
Sat Dec 07, 2019 2:53 pm
Forum: General Science Questions
Topic: Final Content
Replies: 3
Views: 39

Re: Final Content

Yes the material is cumulative but will focus on material after the midterm.
by AKhanna_3H
Sat Dec 07, 2019 9:58 am
Forum: Lewis Acids & Bases
Topic: 6A.17
Replies: 1
Views: 12

6A.17

This question asks whether the following oxides are acidic, basic, or amphoteric: a. BaO b. SO3 c. As2O3 d. Bi2O3
I understand the definitions of acids, bases, and what it means to be amphoteric, but how do you know what each oxide is?
by AKhanna_3H
Fri Dec 06, 2019 3:58 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: AX4 geometry in coordination comppounds
Replies: 2
Views: 21

Re: AX4 geometry in coordination comppounds

AX4 is for tetrahedral molecules. Square planar molecules have four bonding regions and two sets of lone pairs, or AX4E2.
by AKhanna_3H
Wed Dec 04, 2019 12:08 am
Forum: Naming
Topic: naming email
Replies: 2
Views: 42

Re: naming email

What email is it? Is there anyway you can send a screenshot because I cannot find that email
by AKhanna_3H
Tue Dec 03, 2019 8:19 pm
Forum: Naming
Topic: Memorizing
Replies: 9
Views: 51

Re: Memorizing

Does someone have a screenshot of the table he sent us I can't seem to find it in my email? Thanks!
by AKhanna_3H
Tue Dec 03, 2019 12:17 pm
Forum: General Science Questions
Topic: Exam Subjects
Replies: 5
Views: 58

Re: Exam Subjects

I believe the exam is cumulative but will emphasize topics after the midterm.
by AKhanna_3H
Mon Dec 02, 2019 11:30 pm
Forum: General Science Questions
Topic: Final test locations
Replies: 4
Views: 41

Re: Final test locations

These are the room assignments he posted on his website, hope this helps!
by AKhanna_3H
Mon Dec 02, 2019 11:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Marshmallow
Replies: 1
Views: 68

Re: Marshmallow

After the review session on Friday!
by AKhanna_3H
Mon Dec 02, 2019 11:18 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 9 and 10 Homework
Replies: 2
Views: 37

Re: Week 9 and 10 Homework

I think anything from the coordination compounds and acid and base structures on the syllabus should be ok!
by AKhanna_3H
Mon Dec 02, 2019 11:15 pm
Forum: Naming
Topic: Hw 9c.1 part c
Replies: 5
Views: 41

Re: Hw 9c.1 part c

The formula gives us (OH2) which indicates aqua, if it was (OH), that would be hydroxido
by AKhanna_3H
Mon Dec 02, 2019 10:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Grades
Replies: 15
Views: 131

Re: Grades

Besides the 50% required to get a C-, Dr. Lavelle does not determine the grade cutoffs for an A, A-, B+, etc. until after the final, meaning you may not have to get the standard 93% to get an A in the class. It all depends on the overall scores at the end.
by AKhanna_3H
Mon Dec 02, 2019 4:06 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 4
Views: 45

Re: Electron Configuration

Dr. Lavelle explained that the configurations should be written in order of energy level, so 3d would come before 4s.
by AKhanna_3H
Mon Dec 02, 2019 4:03 pm
Forum: Hybridization
Topic: Lone Pairs
Replies: 2
Views: 17

Re: Lone Pairs

Since lone pairs count as a region of electron density, I believe they would count towards hybridization. For example, in a water molecule, the oxygen has two lone pairs and two covalent bonds, and would have a hybridization of sp3.
by AKhanna_3H
Mon Dec 02, 2019 3:59 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: seesaw
Replies: 4
Views: 39

Re: seesaw

Dr. Lavelle said in a previous post that the seesaw is a topic covered in 14B and we do not need to explicitly know this for the final.
by AKhanna_3H
Mon Dec 02, 2019 3:57 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Pka
Replies: 2
Views: 21

Re: Pka

large Ka/small pKa = strong acid
small Ka/large pKa = weak acid
by AKhanna_3H
Mon Dec 02, 2019 3:51 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: how to find pH
Replies: 4
Views: 36

Re: how to find pH

According to a previous post, Dr. Lavelle said that we would not have to calculate one from the other, but it is important to know that when you put an acid in a solution with a pKa less than the pH of the solution the acid will dissociate.
by AKhanna_3H
Mon Dec 02, 2019 3:48 pm
Forum: Lewis Structures
Topic: 2D.3
Replies: 2
Views: 25

Re: 2D.3

Ba and Br have the highest difference in electronegativity according to periodic table trends, therefore the bonds in BaBr2 are primarily ionic
by AKhanna_3H
Tue Nov 19, 2019 11:19 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 bond
Replies: 3
Views: 22

Re: hydrogen bond

Hydrogen bonds form because hydrogen has a partially positive charge, and hydrogen atoms form hydrogen bonds with extremely electronegative atoms with partially negative charges. These atoms are Fluorine, Oxygen, and Nitrogen.
by AKhanna_3H
Wed Nov 13, 2019 2:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Regrade requests
Replies: 3
Views: 68

Regrade requests

If I went through the solutions and feel as if I should have received points that I did not get, is there a way to do a regrade request?
by AKhanna_3H
Wed Nov 13, 2019 1:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Class grading
Replies: 12
Views: 197

Re: Class grading

Final grades are not assigned until the end of the quarter once the averages are determined. Just try to get as many points as possible throughout the course.
by AKhanna_3H
Thu Nov 07, 2019 11:12 am
Forum: Bond Lengths & Energies
Topic: Test 2 Topics
Replies: 40
Views: 355

Re: Test 2 Topics

Material after the midterm to what we have learned just before the test
by AKhanna_3H
Thu Nov 07, 2019 11:11 am
Forum: Student Social/Study Group
Topic: Class Grading
Replies: 35
Views: 485

Re: Class Grading

The class is not curved and letter grades are not assigned to tests and midterms. At the end of the quarter Dr. Lavelle will create the cutoffs for A/A-/B+ etc. depending on what the end points are. This means that to get an A in the class you may have to get a different percentage than the standard...
by AKhanna_3H
Thu Nov 07, 2019 11:07 am
Forum: Balancing Chemical Reactions
Topic: Balancing This Equation
Replies: 11
Views: 102

Re: Balancing This Equation

Combustion reactions always have O2 as a reactant and H20 and C02 as products.
by AKhanna_3H
Thu Nov 07, 2019 11:03 am
Forum: Octet Exceptions
Topic: Why can't Aluminum have an expanded octet?
Replies: 5
Views: 61

Re: Why can't Aluminum have an expanded octet?

Aluminum does not have an expanded octet. Since it is a group 3 atom it sometimes violates the octet rule by having less than 8 valence electrons when bonded.
by AKhanna_3H
Thu Nov 07, 2019 10:43 am
Forum: Lewis Structures
Topic: Does the shape that I draw the Lewis structure matter?
Replies: 14
Views: 67

Re: Does the shape that I draw the Lewis structure matter?

Since we have not talked about shapes yet in lecture I would say you probably do not have to worry about the shapes of Lewis structures. Once we learn it then you will have to take shape into account.
by AKhanna_3H
Sat Nov 02, 2019 3:43 pm
Forum: Ionic & Covalent Bonds
Topic: The net energy decrease when Na and Cl form NaCl
Replies: 2
Views: 24

Re: The net energy decrease when Na and Cl form NaCl

Na and Cl independently are less stable than when they are bonded because they have incomplete octets as ions. They bond together to achieve a lower energy state and are more stable.
by AKhanna_3H
Sat Nov 02, 2019 3:37 pm
Forum: Electronegativity
Topic: Oxygen and Electronegativity
Replies: 5
Views: 26

Re: Oxygen and Electronegativity

Electronegativity is a measure of the tendency of an atom to form a covalent bond. Fluorine is the most electronegative atom on the periodic table, meaning it has the highest tendency to form a covalent bond. Since Oxygen is close to Fluorine, it also has a relatively high electronegativity. Electro...
by AKhanna_3H
Sat Nov 02, 2019 3:28 pm
Forum: Dipole Moments
Topic: London Dispersion vs Van der waals
Replies: 2
Views: 23

Re: London Dispersion vs Van der waals

Dr. Lavelle said that these are the same thing, just different words for the same concept!
by AKhanna_3H
Thu Oct 31, 2019 12:00 am
Forum: Lewis Structures
Topic: Textbook question 2B.9
Replies: 1
Views: 26

Re: Textbook question 2B.9

Ions are drawn separated from each other because in ionic bonds, electrons are not shared like in covalent bonds. Rather, electrons are donated or accepted. Therefore, there are no shared electron pairs, and no need to draw single, double, triple bonds between two atoms.
by AKhanna_3H
Mon Oct 28, 2019 10:37 am
Forum: Administrative Questions and Class Announcements
Topic: Review Sessions
Replies: 2
Views: 44

Review Sessions

Are the review sessions for the midterm still happening tonight even though classes are cancelled?
by AKhanna_3H
Sat Oct 26, 2019 5:19 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 5
Views: 44

Re: Lewis Structure

The least electronegative atom goes in the center. Electronegativity increases as you go across the periodic table and decreases as you go down the periodic table.
by AKhanna_3H
Sat Oct 26, 2019 5:14 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 7
Views: 63

Re: Formal Charge

Dr. Lavelle said in lecture that the formal charge of an atom indicates a gain or loss of electrons when forming a covalent bond. Calculating formal charges is helpful in drawing the best possible Lewis structures and making sure that the overall charge of the molecule is represented in the Lewis st...
by AKhanna_3H
Sat Oct 26, 2019 4:25 pm
Forum: Lewis Structures
Topic: Sulfate Lewis Structure (From class)
Replies: 1
Views: 19

Re: Sulfate Lewis Structure (From class)

He started by finding how many valence electrons Sulfur and Oxygen had. Both have 6, and since there are 4 Oxygens present, there are a total of 32 electrons, so your Lewis structure should include 32 electrons. First he drew the diagram with Sulfur in the center and 4 Oxygens each with a single bon...
by AKhanna_3H
Sat Oct 26, 2019 4:04 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Assigning Orbitals to Elements
Replies: 4
Views: 34

Re: Assigning Orbitals to Elements

My TA said that you do not need to know how to do this. I believe he said there is no way to figure it out just from reading a problem, but he definitely said we would not have to do this on a midterm/test. Hope that helps!
by AKhanna_3H
Sat Oct 26, 2019 4:03 pm
Forum: Photoelectric Effect
Topic: kinetic energy
Replies: 6
Views: 50

Re: kinetic energy

The equation for this is on the formula sheet so you don't have to memorize it but you will most likely have to apply it to problems.
by AKhanna_3H
Wed Oct 16, 2019 2:52 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr's Equation
Replies: 5
Views: 53

Re: Bohr's Equation

You might have to double check, but I believe the tests/midterms/finals are similar to the homework problems which involve calculations, so it is unlikely that you would have to derive an equation on a test. Hope this helps!
by AKhanna_3H
Wed Oct 16, 2019 2:49 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal plane for s-orbitals?
Replies: 3
Views: 24

Re: Nodal plane for s-orbitals?

A nodal plane by definition is a plane where the probability of finding an electron is 0. This means there are no planes for the s-orbital where the probability of finding an electron is 0.
by AKhanna_3H
Wed Oct 16, 2019 2:42 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron spin
Replies: 8
Views: 71

Re: Electron spin

I think that as long as you understand that +1/2 indicates a positive spin and -1/2 indicates a negative spin for the fourth quantum number, you should be good!
by AKhanna_3H
Tue Oct 15, 2019 4:42 pm
Forum: *Black Body Radiation
Topic: What is Black Body?
Replies: 6
Views: 84

Re: What is Black Body?

I also believe Dr. Lavelle said that it absorbs all radiation.
by AKhanna_3H
Tue Oct 15, 2019 4:16 pm
Forum: Photoelectric Effect
Topic: Speed of Light
Replies: 29
Views: 153

Re: Speed of Light

Yes it is a constant.
by AKhanna_3H
Sat Oct 12, 2019 8:25 pm
Forum: DeBroglie Equation
Topic: Knowing Which Equation to Use
Replies: 4
Views: 44

Re: Knowing Which Equation to Use

I usually start by figuring out what variables I know and then finding an equation that has the unknown variable in it, filling in all the known variables that apply to that equation.
by AKhanna_3H
Sat Oct 12, 2019 8:09 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Decreasing gap between energy level
Replies: 6
Views: 59

Re: Decreasing gap between energy level

As an electron gets farther away from the nucleus, the "pull" of the nucleus decreases in strength. Therefore the easier it is for an electron to jump to a higher energy level the farther away from the nucleus it is.
by AKhanna_3H
Sat Oct 12, 2019 8:02 pm
Forum: SI Units, Unit Conversions
Topic: Weekly Posts
Replies: 7
Views: 64

Re: Weekly Posts

You have to post 5 times by Sunday at 11:59 p.m.
by AKhanna_3H
Thu Oct 10, 2019 4:03 pm
Forum: SI Units, Unit Conversions
Topic: Course Reader
Replies: 6
Views: 94

Re: Course Reader

There is no course reader, the only required material is the textbook which also comes with a solution manual.
by AKhanna_3H
Wed Oct 09, 2019 3:11 pm
Forum: Limiting Reactant Calculations
Topic: Problem M.5
Replies: 2
Views: 50

Problem M.5

Could someone please explain how to approach problem M.5? Thanks!
by AKhanna_3H
Thu Oct 03, 2019 7:31 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Rounding
Replies: 12
Views: 160

Re: Rounding

In general, you would use the full number and then round to the correct number of significant figures as the last step of your calculations to get your final answer. For the most accuracy, avoid rounding any numbers in your calculations until the final answer.
by AKhanna_3H
Thu Oct 03, 2019 6:44 pm
Forum: SI Units, Unit Conversions
Topic: Chemistry Community Question
Replies: 3
Views: 40

Re: Chemistry Community Question

I also remember Dr. Lavelle saying the posts were due by 11:59 p.m. Sunday.
by AKhanna_3H
Thu Oct 03, 2019 4:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Will there be lecture on Nov. 27?
Replies: 3
Views: 75

Re: Will there be lecture on Nov. 27?

You won't be penalized for missing lecture since this class does not use clickers or participation points. Some professors cancel their lectures on Wednesday if they know a lot of students won't be there, but I'm not sure about Dr. Lavelle.
by AKhanna_3H
Thu Oct 03, 2019 3:39 pm
Forum: Empirical & Molecular Formulas
Topic: Faster way to find molecular formula?
Replies: 3
Views: 48

Re: Faster way to find molecular formula?

Unfortunately there is no faster way, since the empirical formula gives you the ratio to find the molecular formula.
by AKhanna_3H
Thu Oct 03, 2019 12:11 am
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 129
Views: 2876

Re: Advice from a Medical Student - Part II [ENDORSED]

It is great to learn about the medical school journey from a someone who was in my position just a few years ago. Thank you for sharing!

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