CHEMISTRY COMMUNITY

Chem 14B Midterm Wednesday Feb. 15 from 6 to 8pm.

Students MUST go to their assigned room.

14B-1, 11am class:
Last name A-L in Moore 100
Last name M-Z in Broad 2160E

14B-2, 1pm class:
Last name A-L in Haines 39
Last name M-Z in LaKretz 110

14B-3, 3pm class:
Last name A-K in Franz 1178
Last name L-R in CS 76
Last name S-Z in KNSY PV 1220B

Midterm is 1hr 50mins
5 Questions
All material up to and including electrochemistry.
In the Course Reader it is all material up to page 54.

For review work through past midterms (p.122-162 in Course Reader).
Homework questions will be on the midterm.
Bring a pen, simple scientific calculator, photo ID.
Nothing else, no cell phones, no graphing calculators, etc.

Additional Math Assistance Resources
See New Math Materials Section On My Class Website
See Math Office Hours

See New Electrochemistry Section On My Class Website.

 
MANY Review Sessions

Wednesday Feb 8, CS50
6-7pm, Sophia King - Balancing redox equations, half cells and possibly Nernst equation
7-8pm, Dimitri Bikos

Thursday Feb 9, CS76
6-7pm, Christopher Sue: General Overview topics, mainly formulas and Thermodynamic questions from Midterm 2013
7-8pm, Jack Fuller - First and Second Laws

Friday Feb 10, Broad 2160E
4:15-5:30pm, Dr. Lavelle (Review conceptually important questions from Winter 2016 Midterm, and student's questions.)

Friday Feb 10, Franz 1178
6-7pm, Dan Zhu (Electrochemistry)
7-8pm, Katherine Bay (Quiz 1)

Saturday Feb 11, LaKretz 110
2-3pm, Andrew Dawson (Open to questions, combining concepts and complex questions, brief overview)
4-5pm, Andy Smaligo (2014 Final Q1-Q3, anything else you may want)

Sunday Feb 12, LaKretz 110
2-3pm, Marcus Jellen (Phase Changes)
3-4pm, Roselyn Rodrigues (Winter 2014 Midterm, Q3-8, and general questions)
4-5pm, Zhiyu Liu (Winter 2013 Midterm Q1-6)

Monday Feb 13, CS76
6-7pm, Kris Marsh - Entropy, Gibbs Free Energy, Nernst Equation
7-8pm, Yolanda Li (Winter 2015 Midterm, Q1-5, possibly more if time allows)

Tuesday Feb 14, CS50
6-7pm, Dane Stanfield
7-8pm, Yekan Wang (Discuss questions that are commonly asked on Chemistry Community, common mistakes that people made on the midterm 2016 and quiz 1)

In addition to:
32 Office Hours per Week
28 Peer Learning Sessions per Week
Chemistry Community 24/7
Discussion Sections

Will we need to do derivations on the midterm? Or will it be similar to last quarter where we did not need to worry about them? Thanks!

Whatever I have covered in class can be expected.

For the review sessions, are they identical or are certain sessions reviewing specific topics?

Thank you!

Each review session is individual/unique.

Will a list of the topics covered in each review session be posted here soon?

Will electrolytic cells and how they work need to be known for midterm ?

sophianguyen_1N wrote:Will a list of the topics covered in each review session be posted here soon?

They were posted today (Tuesday), and more will be added.

Nicholas wrote:Will electrolytic cells and how they work need to be known for midterm ?

This was briefly covered in class and not many HW questions. I am unable to answer individual topic questions on what is or is not on the exam.

My exam questions cover the main topics we spent the most time on in class and HW questions.

Will the Feb. 10 review session by Dr. Lavelle be podcasted like last quarter?

Michelle_Li_1H wrote:Will the Feb. 10 review session by Dr. Lavelle be podcasted like last quarter?

I have asked Bruincast many times to webcast my review session and their response is no.
I have spent much time on this communicating with OID Director and Deans.

Official UCLA response is they don't have the resources to webcast review sessions.

I am in the process of trying to make alternative arrangements. When I have an answer I will announce it.

Will any other review sessions be Bruincasted if we cannot make it at the given time?

Will the quiz solutions be provided to us or do we need to seek help from a T.A. or U.A. regarding our questions?

Jasmine_Wong_2K wrote:Will any other review sessions be Bruincasted if we cannot make it at the given time?

As stated above Bruincast will not even Webcast my (Dr. Lavelle) review session ...

Patrick_Mac_3D wrote:Will the quiz solutions be provided to us or do we need to seek help from a T.A. or U.A. regarding our questions?

Some review sessions are going through Quiz 1.
Also ask Quiz 1 questions in the ~60 hours per week of office hours and peer learning sessions.

Will there still be a lecture the day of the midterm?

megan_thi_2j wrote:Will there still be a lecture the day of the midterm?

Still to be decided and announced in class.

Chem_Mod wrote:

Michelle_Li_1H wrote:Will the Feb. 10 review session by Dr. Lavelle be podcasted like last quarter?

I have asked Bruincast many times to webcast my review session and their response is no.
I have spent much time on this communicating with OID Director and Deans.

Official UCLA response is they don't have the resources to webcast review sessions.

I am in the process of trying to make alternative arrangements. When I have an answer I will announce it.

I have organized a video camera with tripod for my review session!
This morning a student from lecture 1 kindly volunteered to assist with the video camera.

After my review session (tonight) I will copy over video and upload it here to Chemistry Community.

Questions I review are from Winter 2016 Midterm.

Part 1 of my Friday Midterm Review.

I'm not sure if this has been answered before, but do we have class on the Wednesday of the midterm?

Part 2 of the Friday Midterm Review.

Does each review session have a certain focus on certain problem types/topics that are preplanned already?

Part 3 of the Friday Midterm Review.

I am having trouble viewing the midterm review session. Is there any one else having this problem? It says the plugin is not supported when I try and watch it.

It said the same thing for me (plugin not working). Try downloading it by clicking on the "Part 1.mp4" file - do the same for all 3 files. I downloaded it and can watch it now

Ashley Curtis 2O wrote:I am having trouble viewing the midterm review session. Is there any one else having this problem? It says the plugin is not supported when I try and watch it.

I believe you can also click on the link to download it, if the plug-in is not working.

If I could not attend a review session due to schedule conflicts, is it not possible to access that review session on my own time?

I would have really liked to go over some topics covered in a recent review session but could not make it due to another commitment. Are the TA review sessions also recorded and uploaded somewhere, or is it just Dr. Lavelle's?

As I am going over past midterms in the course reader I noticed that for certain problems points are deducted for not having the correct sig figs, while for other problems, sig figs were not taken into account for the total points. I was wondering for this midterm if sig figs will be a part of our total points for all the problems or if they will not be accounted for or if it's going to be a mixture of both?

Henry_Shin_3B wrote:If I could not attend a review session due to schedule conflicts, is it not possible to access that review session on my own time?

I would have really liked to go over some topics covered in a recent review session but could not make it due to another commitment. Are the TA review sessions also recorded and uploaded somewhere, or is it just Dr. Lavelle's?

I'm pretty sure only Dr. Lavelle's review session will be recorded; he even had to personally record and upload the videos he took of his review session because Bruincast, for whatever reason, refused to.

Chin_Alyssa_3I wrote:As I am going over past midterms in the course reader I noticed that for certain problems points are deducted for not having the correct sig figs, while for other problems, sig figs were not taken into account for the total points. I was wondering for this midterm if sig figs will be a part of our total points for all the problems or if they will not be accounted for or if it's going to be a mixture of both?

Some (not all) questions will have 1pt assigned to sig figs.
Since the midterm is 110 points sig fig will be a very low %.

Even if every question had a sig fig point (which they don't) it would be a maximum of 5 points out of 110 points.

Today, the forum's video player was upgraded to HTML5. Plugins should no longer be needed. Also posts with videos now load much faster.

Has it been decided whether or not we will have lecture on the day of the midterm?

Was wondering if any of you would be able to answer the pikachu question for Winter 2014 Final Part A

Nilla Sivakumar 2H wrote:Has it been decided whether or not we will have lecture on the day of the midterm?

I believe that Dr. Lavelle said that he has not yet made a decision as to whether or not we will have lecture on the day of the midterm.

I would also like to know if we should know any specific derivations for the midterm. I know we haven't been tested on them in the past but there was a fairly large focus on the derivations of thermodynamics equations using the ideal gas law. Thank you!

Randon_Zahlout_3B wrote:I would also like to know if we should know any specific derivations for the midterm. I know we haven't been tested on them in the past but there was a fairly large focus on the derivations of thermodynamics equations using the ideal gas law. Thank you!

As posted several times: Everything I cover in class can be tested.

However the main emphasis is knowing the concepts and applying them to solve problems. Derivations can and are asked, but typically +90% are problem solving type questions.

Hope this helps.

No class Wednesday due to midterm. :-)

I can now announce this as we are on schedule (with no last minute fire alarm disrupting Monday's class, etc.).

FOR QUESTION 1a ON MIDTERM FOR WINTER 2016. WHY ARE MOLES BEING IGNORED IN THE EQUATION?

For Practice Midterm 2013, question 5b asks to "arrange the following substances in order of increasing standard molar entropy: CHF3, CF4, CH3F, CH2F2"

The answer says CH3F<CH2F2<<CHF3<CF4

This seems incorrect, as CF4 should have the least molar entropy and CH2F2 should have the greatest (due to positional disorder). I think the order should be CF4<CH3F<CHF3<CH2H2

What is the correct order?

For the Winter 2013 midterm, question 2B, I can't get the answer despite following along exactly. I keep getting 57 degrees instead of 64.

55000 = 275(4.814)(deltaT)

Nilla Sivakumar 2H wrote:For the Winter 2013 midterm, question 2B, I can't get the answer despite following along exactly. I keep getting 57 degrees instead of 64.

55000 = 275(4.814)(deltaT)

Never mind. I was using the wrong value for the heat capacity of water.

Armani Dodson 1A wrote:FOR QUESTION 1a ON MIDTERM FOR WINTER 2016. WHY ARE MOLES BEING IGNORED IN THE EQUATION?

All reactants and products are one mole. Therefore the can be kJ or kJ.mol^-1.

I mentioned this in class. We often accept both units unless the question explicitly asks what is the enthalpy change per mole of reactant or product, or asks for the standard enthalpy of formation. Then the answer must have units: kJ.mol^-1

Derek_Petrosian_3I wrote:For Practice Midterm 2013, question 5b asks to "arrange the following substances in order of increasing standard molar entropy: CHF3, CF4, CH3F, CH2F2"

The answer says CH3F<CH2F2<<CHF3<CF4

This seems incorrect, as CF4 should have the least molar entropy and CH2F2 should have the greatest (due to positional disorder). I think the order should be CF4<CH3F<CHF3<CH2H2

What is the correct order?

Standard molar entropy is the entropy for one mole of a compound at 1atm and 25^oC.

All four compounds have 4 atoms and 4 bonds, but CF₄ has the greatest number of electrons, protons, and neutrons (highest molar mass) and therefore the highest standard molar entropy.

Your answer addresses residual entropy: the remaining structural or positional entropy on cooling to 0K.

See the example I did in class on page 29 of the course reader.

On Midterm 2013 Question 7, we seem to assume (after balancing the redox equation) that the number of moles we're dealing with is 10. Is that number taken off of the reduction half-equation, where we end up with 10 moles of bromide ions? Does this always apply (i.e. we always deal with the number of moles of anions left over after reduction)?

Regarding Sig figs, should we keep rounding to the right sig fig throughout the whole question or should we keep using the calculator`s stored values and then just round at the end?

Nilla Sivakumar 2H wrote:On Midterm 2013 Question 7, we seem to assume (after balancing the redox equation) that the number of moles we're dealing with is 10. Is that number taken off of the reduction half-equation, where we end up with 10 moles of bromide ions? Does this always apply (i.e. we always deal with the number of moles of anions left over after reduction)?

Same as what I did in class: Balance the redox reaction such that the stoichiometric coefficients are all whole numbers and the electrons in the two half-reactions balance.

Caleb Lim 2M wrote:Regarding Sig figs, should we keep rounding to the right sig fig throughout the whole question or should we keep using the calculator`s stored values and then just round at the end?

Only round off at the very end.

Does anyone know if there are any of questions from the past midterms that cover material that will not be on the 2017 midterm?

What's the difference between and irreversible process and a reversible process?

leilarishwain_3H wrote:What's the difference between an irreversible process and a reversible process?

A reversible process is one where T is constant and V increases while P decreases. For reversible/isothermal processes, we use the equation: w=-nRTln(V2/V1). For irreversible processes, T changes, and we use the equation: w=-P. In reversible/isothermal processes more work is done while in irreversible processes, less work is done.

marinarosebrock wrote:Does anyone know if there are any of questions from the past midterms that cover material that will not be on the 2017 midterm?

All material covering thermochemistry, thermodynamics, and electrochemistry is the same.

Will values like specific heat of different compounds/ elements be given when they're necessary or should I memorize a few basic ones like water, ice and steam?

usernamesarehard wrote:Will values like specific heat of different compounds/ elements be given when they're necessary or should I memorize a few basic ones like water, ice and steam?

It was said we would be given equations and values that we would need for the test, so the specific heat, the value of R and F etc should be given on our equations sheet

Is KNSY PV the Kinsey Pavillion near the inverted fountain?

I notice that every midterm in the past four years has been 8 questions, while this year there is only 5.
Will each question simply have more subparts, with the same difficulty as the previous midterms, or should we expect something more challenging than the past four years?

Molika Soben_3J wrote:Is KNSY PV the Kinsey Pavillion near the inverted fountain?

Use this UCLA Map: http://maps.ucla.edu/campus/

Henry_Shin_3B wrote:I notice that every midterm in the past four years has been 8 questions, while this year there is only 5.
Will each question simply have more subparts, with the same difficulty as the previous midterms, or should we expect something more challenging than the past four years?

More subparts, but overall shorter.

When will be able to see the results of our midterm

A quick question: Are we allowed to ask questions about midterm problems on Chemistry Community now or do we have to wait until we get our exams back?

AllanNicholson2F wrote:When will be able to see the results of our midterm

Midterms will be handed back next week Wednesday in class.

Suk Jin Song 3L wrote:A quick question: Are we allowed to ask questions about midterm problems on Chemistry Community now or do we have to wait until we get our exams back?

Wait until you get your exams back.
The detailed solutions will be posted on my class website next week Wednesday after exams are returned in class that same day.

Will we get the Midterms back after Lecture on Wednesday ?

hannahbrown-north3E wrote:Will we get the Midterms back after Lecture on Wednesday ?

Yes, as announced via MyUCLA email.
Check your MyUCLA email settings to make sure you get class email announcements.

If we were unable to make class on Wednesday, how will we able to get our midterm?

Your TA has your midterm and they can be collected in your TA's office hours and/or your discussion section.

Sorry, if Lavelle already mentioned it, but what was the average for the midterm?
Thanks!

I believe the average was a 74% on the Midterm.

Have the solutions been posted anywhere yet?

If I got a wrong answer in question 5 part a, and then used that wrong answer correctly in part b, should I have gotten full credit for part b, or minus one point for part b? I already lost 4 points in part a, so I feel like losing a point in part b is getting punished twice.. Anyone know how this should work?

Rachel Wile 2D wrote:I believe the average was a 74% on the Midterm.

Correct

Josephine_Tang_1N wrote:Have the solutions been posted anywhere yet?

Yes, as I announced in class: They are posted on my class website.
https://lavelle.chem.ucla.edu/class-websites/chem14b/

If we weren't able to make it to lecture on Wednesday, what is another option to obtain our midterm?

Sebastian wrote:If we weren't able to make it to lecture on Wednesday, what is another option to obtain our midterm?

I would email your TA to ask if they can bring it to office hours or your next discussion

Why was the change of entropy of the outside greater than the inside on the midterm question?

This will be the first time ever I am doing an additional review session going through the midterm after it was taken. I think it will be very informative and helpful.

I have organized this additional review session for this coming Friday March 3rd, and reserved CS50 from 4-5pm.

All midterm questions will be answered.

Chem_Mod wrote:This will be the first time ever I am doing an additional review session going through the midterm after it was taken. I think it will be very informative and helpful.

I have organized this additional review session for this coming Friday March 3rd, and reserved CS50 from 4-5pm.

All midterm questions will be answered.

Is there any possibility that this could be recorded and posted like the review session was?

Just wondering, is there any curve applied to the midterm? Thanks

As stated in the Syllabus and Exam schedule grades are only assigned at the end of the quarter, and 50% or higher is needed to pass with a C- or higher.

Isabella_Pena_3D wrote:

Chem_Mod wrote:This will be the first time ever I am doing an additional review session going through the midterm after it was taken. I think it will be very informative and helpful.

I have organized this additional review session for this coming Friday March 3rd, and reserved CS50 from 4-5pm.

All midterm questions will be answered.

Is there any possibility that this could be recorded and posted like the review session was?

Bruincast will not offer this service for review sessions. I am working on alternatives to organize something for my students.

Hello Dr Lavelle,

Will the additional review session tomorrow be recorded?

Katrina_Domingo_3G wrote:Hello Dr Lavelle,

Will the additional review session tomorrow be recorded?

I was wondering the same thing; I know Dr. Lavelle made an announcement in class about having students volunteer to record the session, but does anyone know if the recordings were posted on Chemistry Community? Thanks in advance!

Rika Jitosho 2E wrote:

Katrina_Domingo_3G wrote:Hello Dr Lavelle,

Will the additional review session tomorrow be recorded?

I was wondering the same thing; I know Dr. Lavelle made an announcement in class about having students volunteer to record the session, but does anyone know if the recordings were posted on Chemistry Community? Thanks in advance!

Just found the posting of the review session! You can find it here:

viewtopic.php?f=160&t=20107

Where could I pick up my midterm if I was unable to get it from my TA initially?

Midterm and quizzes are available from your TA in your TA's office hours.

How heavily will the final cover pre organic chemi material ?

This thread is for the midterm.

See Final Exam Winter 2017 for answer.

I can't find the midterm 2017 (aka the one we took) answers with the explanations is it is this thread? Or did lavelle post it elsewhere pls help I want to go over my midterm before the final.

ChristinaRoble3J wrote:I can't find the midterm 2017 (aka the one we took) answers with the explanations is it is this thread? Or did lavelle post it elsewhere pls help I want to go over my midterm before the final.

Check Dr. Lavelle's 14B Class Website