Search found 59 matches
- Sun Mar 17, 2019 7:31 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: U=0
- Replies: 6
- Views: 3189
Re: U=0
Yes, I think w always =-q
- Sun Mar 17, 2019 7:22 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Grade Release Date?
- Replies: 7
- Views: 1005
Re: Final Grade Release Date?
The final grades should be out before April 1st. I think we'll get an email of where and when to pick up our exams, last quarter I think it was week 2 or 3!
- Sun Mar 17, 2019 7:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chemistry community posts
- Replies: 5
- Views: 1018
Re: Chemistry community posts
I remember Dr. Lavelle saying that we have to post 3 times per week and that's what is written on the syllabus, but if last quarter it just had to add up to 30 in total, I'm not completely sure if its the same for this quarter too.
- Sun Mar 10, 2019 10:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Questions
- Replies: 10
- Views: 1221
Re: Final Questions
Dr Lavelle said that there will be 8 questions, however, each question is composed of multiple sections! I find it helpful to look at previous finals to familiarize yourself with the formatting as well
- Sun Mar 10, 2019 10:03 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 18
- Views: 2065
Re: Final
I don't think there's an exact percentage as everything is fair game, but the newer material might be emphasized more.
- Sun Mar 10, 2019 10:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Final Exam
- Replies: 23
- Views: 1831
Re: Final Exam
The final is cumulative, so everything covered this quarter will be included!
- Sun Mar 03, 2019 11:10 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Does anyone know if test 2 will be curved?
- Replies: 15
- Views: 3027
Re: Does anyone know if test 2 will be curved?
Each test/exam usually isn't curved. However, if our final grades are curved, it will be in our favor and should only be to improve our scores
- Sun Mar 03, 2019 11:07 pm
- Forum: Balancing Redox Reactions
- Topic: Order in Cell diagrams
- Replies: 3
- Views: 528
Re: Order in Cell diagrams
The order is usually like the following: (s)|(g)|(aq),(aq)||(aq),(aq)|(g)|(s). Liquids aren't included.
- Sun Mar 03, 2019 11:05 pm
- Forum: Balancing Redox Reactions
- Topic: Short hand notation
- Replies: 8
- Views: 868
Re: Short hand notation
The salt bridge connects the 2 half cells and provides a path for migration of cations and anions. Voltaic cells generate electricity and the salt bridge reduces the voltage produced.
- Sun Feb 24, 2019 11:05 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell diagram
- Replies: 4
- Views: 398
Re: Cell diagram
The anode (oxidation, -ve electrode) is on the left, and cathode (reduction, +ve electrode) is on the right.
- Sun Feb 24, 2019 10:43 pm
- Forum: Student Social/Study Group
- Topic: Test #2
- Replies: 7
- Views: 706
Re: Test #2
Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7).
- Sun Feb 24, 2019 10:42 pm
- Forum: Student Social/Study Group
- Topic: Test
- Replies: 17
- Views: 1593
Re: Test
Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7).
- Sun Feb 17, 2019 11:15 pm
- Forum: Student Social/Study Group
- Topic: Test
- Replies: 17
- Views: 1593
Re: Test
Test 2 includes materials after the midterm, and like everyone said, Dr. Lavelle said that - Test 2 covers all topics on Gibbs free energy and electrochemistry up to the Nernst equation.
- Sun Feb 17, 2019 11:13 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Midterm Grades
- Replies: 35
- Views: 2798
Re: Midterm Grades
It usually takes a week, so maybe we'll get it during our discussion sessions week 7 or Friday after class!
- Sun Feb 17, 2019 11:11 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: HW for W7
- Replies: 7
- Views: 694
Re: HW for W7
Like everyone said, Dr. Lavelle said to "Hand in Week 7 homework in discussion section on Thermodynamics including Gibbs Free Energy."
- Sun Feb 10, 2019 11:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm 2019
- Replies: 9
- Views: 900
Re: Midterm 2019
On the class website its posted that the midterm covers: Chemical Equilibrium, Acid and Base Equilibria, Thermochemistry, Thermodynamics to the end of entropy.
- Sun Feb 10, 2019 11:21 pm
- Forum: Ideal Gases
- Topic: Lyndon's review session
- Replies: 7
- Views: 834
Re: Lyndon's review session
Also he usually posts the answers after the review session, but to get the solution and how to get to the final answer I recommend going to his review session!
- Sun Feb 10, 2019 11:18 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Midterm #1 14B
- Replies: 17
- Views: 2211
Re: Midterm #1 14B
His midterm review is under the key word "hotdog". He usually posts just the answers for each question after the review session but he will go through each problem (with working out) during his review session!
- Sun Feb 03, 2019 10:08 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Material on Midterm?
- Replies: 9
- Views: 877
Re: Material on Midterm?
As stated on the class website: Midterm covers: Chemical Equilibrium, Acid and Base Equilibria, Thermochemistry, Thermodynamics to the end of entropy
- Sun Feb 03, 2019 10:04 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Midterm [ENDORSED]
- Replies: 49
- Views: 4936
Re: Midterm [ENDORSED]
HW problems are a good way of preparing and practicing similar types of problems for the midterm. Also I believe that Dr Lavelle always puts 1 question from the hw on the exams.
- Sun Feb 03, 2019 10:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm
- Replies: 12
- Views: 2161
Re: Midterm
There are numerous review sessions held by the TA's and the UA's all of which Dr. Lavelle will post in this upcoming week! The review sessions cover certain topics so it is useful to go to the one's you have most trouble with. I find that going through hw problems is the most effective way to study ...
- Sun Jan 27, 2019 11:47 pm
- Forum: Phase Changes & Related Calculations
- Topic: Due date for Discussion Questions
- Replies: 8
- Views: 885
Re: Due date for Discussion Questions
Homework questions are due in discussion sections every week and chemistry community is due every Sunday at 11:59
- Sun Jan 27, 2019 10:37 pm
- Forum: Ideal Gases
- Topic: Chemistry Community Posting
- Replies: 7
- Views: 633
Re: Chemistry Community Posting
The cutoff is 11:59pm every Sunday!
- Sun Jan 27, 2019 10:35 pm
- Forum: Ideal Gases
- Topic: Approximations for ICE
- Replies: 20
- Views: 1651
Re: Approximations for ICE
Like everyone said, we make the approximation when K is small - less than 10^-3.
- Sun Jan 20, 2019 8:00 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure
- Replies: 8
- Views: 774
Re: Pressure
reaction response to minimize the effect of an increasing pressure by decreasing volume. When volume decreases and there are more moles of gas on the left then the reaction --> and favors products. When volume decreases and there are more moles of gas on the right then the reaction <---- favors reac...
- Sun Jan 20, 2019 7:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentrations Effect on K
- Replies: 8
- Views: 554
Re: Concentrations Effect on K
Like explained in lecture, change in concentration as well as change in pressure - k does not change.
- Sun Jan 20, 2019 6:59 pm
- Forum: Student Social/Study Group
- Topic: test 1
- Replies: 10
- Views: 1193
Re: test 1
Like everyone else said, and according to the announcement: Test 1 covers Equilibrium and Acid & Base Equilibria which is outline 1&2.
- Sun Jan 13, 2019 9:47 pm
- Forum: Student Social/Study Group
- Topic: New to Lavelle
- Replies: 32
- Views: 5330
Re: New to Lavelle
Going through lecture notes, as well as hw problems, and step up sessions (if you can't attend a few some worksheets are posted on chemistry community) help a lot!
- Sun Jan 13, 2019 9:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: solids and liquids
- Replies: 5
- Views: 590
Re: solids and liquids
Because molar concentration of a pure substance (solid or liquid) does not change in a reaction and is therefore not included in equ. constant
- Sun Jan 13, 2019 9:37 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Determining Which side is favored
- Replies: 5
- Views: 703
Re: Determining Which side is favored
To determine which direction a reaction will proceed, we have to calculate the reaction quotient (Q) at any time during reaction and compare it to K. If Q<K there are more reactants than products, therefore more products will be formed and the forward reaction is favored.
- Sun Dec 09, 2018 10:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: AX3E
- Replies: 18
- Views: 3293
Re: AX3E
It is sp3 hybridized and because there is a lone pair, the shape is trigonal pyramidal.
- Sat Dec 08, 2018 8:30 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Shape - 4
- Replies: 3
- Views: 428
Re: Shape - 4
The UA's/TA's said that we will get the mark if we list either tetrahedral or square planar!
- Sat Dec 08, 2018 8:25 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: Why are LDFs everywhere?
- Replies: 3
- Views: 1146
Re: Why are LDFs everywhere?
Are there any exceptions where LDF does not occur in a molecule? From test 3 I was told that formaldehyde does not have London dispersion forces.
- Sun Dec 02, 2018 11:14 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 11
- Views: 1302
Re: Hybridization
The VSPER formula for trigonal planar is AX3. Because it has 3 regions of electron density, it has a hybridization of sp2. If a molecule has 2 regions of electron density it will have a hybridization of sp, 3 = sp2, 4=sp3, 5=sp3d, 6=sp3d2.
- Sun Dec 02, 2018 11:10 pm
- Forum: Hybridization
- Topic: lone pairs
- Replies: 20
- Views: 2139
Re: lone pairs
To figure out hybridization, we need to calculate the steric number which is the number of sigma bonds and number of lone pairs, therefore do have to take lone pairs into account when figuring out the hybridization.
- Sun Dec 02, 2018 11:05 pm
- Forum: Hybridization
- Topic: hybridization
- Replies: 13
- Views: 1825
Re: hybridization
Draw the lewis structure, and calculate the steric number which is the number of sigma bonds and number of lone pairs. Based on the steric number we can figure out the hybridization. E.g. steric number 2 = sp, 3= sp2 and so on.
- Mon Nov 26, 2018 11:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 3
- Replies: 38
- Views: 2697
Re: Test 3
We should revise everything covered on the outline Dr. Lavelle gave, and I find that revising lecture notes and doing as many problems as I can helps the most!
- Mon Nov 26, 2018 11:32 pm
- Forum: Dipole Moments
- Topic: TEST 3: Polarity
- Replies: 7
- Views: 636
Re: TEST 3: Polarity
I agree! the arrow should always point toward the atom with a negative charge.
- Mon Nov 26, 2018 11:28 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: test #3
- Replies: 14
- Views: 1540
Re: test #3
We should understand the reason for bond angles for each VSPER shape and eventually memorize the angles.
- Sun Nov 18, 2018 9:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 7th edition 2E. 21
- Replies: 4
- Views: 364
Re: 7th edition 2E. 21
Dr. Lavelle said he does not expect us to know the specific bond angles, and on exams he will accept answers 'less than'.
- Sun Nov 18, 2018 9:11 pm
- Forum: Properties of Light
- Topic: Test 3
- Replies: 24
- Views: 2234
Re: Test 3
I don't think we'll be directly tested on Lewis Structures, however, we would still need to know how to draw them in order to determine the shape.
- Tue Nov 13, 2018 11:39 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3
- Replies: 8
- Views: 1743
Re: Test 3
Dr Lavelle said that - Test 3 covers: End of Bonding from 3.12 (6 Ed.) and from 2D (7 Ed.); and all of Molecular Shape and Structure (see Syllabus and Outlines for details).
- Sun Nov 11, 2018 11:30 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class Grading
- Replies: 9
- Views: 1163
Re: Class Grading
The syllabus says that the class is not curved, however, from past experience if a class is based on a straight scale (A+ 97% A 93-96% A- 90-92 % and so on) and the average is lower than a B the class will be curved in our favor. But I am not too sure if this applies to Chem14a.
- Sun Nov 11, 2018 11:22 pm
- Forum: Properties of Light
- Topic: Test 3
- Replies: 24
- Views: 2234
Re: Test 3
Dr. Lavelle should post the topics of test 3 soon before the test, but like everyone said it will most likely be topics completed after the midterm
- Sun Nov 11, 2018 11:19 pm
- Forum: Resonance Structures
- Topic: Drawing resonance
- Replies: 17
- Views: 1895
Re: Drawing resonance
In a exam/test situation, I think that it'll be safer to draw the resonance structure of the molecule.
- Sun Nov 04, 2018 10:34 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Test 2 Alveoli question
- Replies: 5
- Views: 704
Re: Test 2 Alveoli question
Some questions give the radius instead of the diameter, in that case would we multiply the radius by 2?
- Sun Nov 04, 2018 10:30 pm
- Forum: Electronegativity
- Topic: Periodic Trends
- Replies: 10
- Views: 1241
Re: Periodic Trends
I usually draw the periodic trends out, so for ionization energy and electronegative since it increases as you go across, and decreases as you go down, I would draw two arrows across the periodic table - the side with the arrow indicating the higher ionization energy/electronegativity. I would then ...
- Sun Nov 04, 2018 10:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: chem test tmrw
- Replies: 6
- Views: 719
Re: chem test tmrw
There will be the same formula page like we had for both test 1 and 2!
- Sun Oct 28, 2018 9:52 pm
- Forum: General Science Questions
- Topic: Khan Academy
- Replies: 10
- Views: 1575
Re: Khan Academy
I personally find Khan Academy a useful addition to studying as, especially if you're a visual learner, Khan academy helps to clarify information that initially seems hard to understand. But I would also recommend to make sure that the videos you are watching are relevant to class material.
- Sun Oct 28, 2018 9:42 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius
- Replies: 8
- Views: 786
Re: Atomic Radius
I believe that we don't have to know the specific values as they will be provided to us if needed. Knowing the trends and justifications will be helpful.
- Sun Oct 28, 2018 9:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 11
- Views: 934
Re: Midterm
Dr. Lavelle posted on the class website that the midterm covers: Fundamentals, Quantum, Bonding to end of 3.11 (6 Ed.) and to end of 2C (7 Ed.)
- Mon Oct 22, 2018 12:58 am
- Forum: Properties of Light
- Topic: Do I have to memorize the spectrum?
- Replies: 20
- Views: 1731
Re: Do I have to memorize the spectrum?
I think that we would be provided with it, but should at least familiarize and understand it beforehand.
- Sun Oct 21, 2018 1:17 am
- Forum: Student Social/Study Group
- Topic: Next week's quiz
- Replies: 5
- Views: 670
Re: Next week's quiz
On the syllabus, it states that the quantum world covers chapter 1 & 2 in the sixth edition, and Focus 1 (omit 1C and 1D.1) in the seventh edition. I think that this test covers the aforementioned chapters with respect to the following topics - photoelectric effect, Heisenberg's uncertainty prin...
- Thu Oct 18, 2018 11:52 am
- Forum: Administrative Questions and Class Announcements
- Topic: Grading
- Replies: 3
- Views: 513
Re: Grading
If a class is not graded on a curve, I'm assuming it's graded using a straight scale: 87-89% = B+, 83-86% = B, 80-82% = B- and so on. I think that this means that it will not hurt if others do better than you. On the syllabus the outline for the final point system is stated, which is out of 500: Wee...
- Sun Oct 14, 2018 5:01 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 41
- Views: 2865
Re: Speed of Light
Will we be provided all of these constants/equations during the tests, midterms and final?
- Sun Oct 14, 2018 4:55 pm
- Forum: Significant Figures
- Topic: When to round the answers to significant figures
- Replies: 11
- Views: 2689
Re: When to round the answers to significant figures
I agree! Keeping extra sig figs during the calculation steps helps to yield the most accurate answer (and rounding the answer at the end). While calculating, I often use the answer stored in my calculator to calculate the next step, so that the most accurate answer will continued to be used for the ...
- Sat Oct 06, 2018 10:20 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical formula set up
- Replies: 9
- Views: 672
Re: Empirical formula set up
I think that since the empirical formula is the relative number of atoms, the easiest method is to solve the problem by imagining that the sample mass is 100g.
- Sat Oct 06, 2018 10:06 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing reactions tips
- Replies: 29
- Views: 2161
Re: Balancing reactions tips
I also usually balance equations using the trial and error method, but like Dr. Lavelle said in class we should always balance the element that occurs the least in the equation. For example, if O Occurs in many species (e.g. 3) and H & C occurs in less species (e.g. 2) we should balance O first ...
- Sat Oct 06, 2018 9:55 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 445078
Re: Rusty on High School Chem [ENDORSED]
I would recommend to look at online videos in addition to the ones posted on the class websites that provide a step by step outline of how to solve different questions. While watching the video, writing the process of the answer out at the same time extremely helps as well. And of course, practicing...