CHEMISTRY COMMUNITY

Rika Jitosho 2E

From what I understand, the "longest chain" refers to the longest continuous chain of carbon-carbon bonds that you identify as the main chain, which will be determined by the number of carbons in that chain (1C is meth-, 2C is eth-, 3C is prop-, etc.) In terms of deciding whether a particu...

Rika Jitosho 2E

In drawing out the transition state (as shown above), are there points associated with writing out the partial charges of the atoms with the partially formed/broken bonds? In other words, will points be deducted if the transition state structure is drawn correctly, but does not include the partial c...

Rika Jitosho 2E

for #1, why do we need "iso" in front of propyl? wouldn't the 4- signify the branching? If you draw out the structure, you'll see the branching of (CH 3 ) 2 CH, which is how you know to include the prefix iso-. By that same logic, if the branching had (CH 3 ) 3 C, you would use the prefix...

Rika Jitosho 2E

Rachel Wile 2D wrote:They would have to specify, but exergonic is much more common than endergonic so if they do not I would draw it the exergonic way.

That's what I was thinking too. Thanks for confirming!

Rika Jitosho 2E

In question 4.35 of the homework, it asks us to draw the reaction profile for the reaction: CH₃Br + OH ---> CH₃OH + Br. I understand how to draw a reaction profile, but how do we know if we should draw the pathway as an exergonic or endergonic reaction? Thanks in advance!

Rika Jitosho 2E

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 adv...

Rika Jitosho 2E

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 adv...

Rika Jitosho 2E

Can anyone please explain question 9 and 10 for quiz 2? I am having a hard time understanding these questions. There is also a helpful thread in the Announcements section titled "Quiz 2 Winter 2017" if you'd like to either verify that your answers are correct, or if you'd like to scroll t...

Rika Jitosho 2E

The solutions manual for question 15.9 also gives a good explanation of how the units for k, rate constant, can differ depending on which reaction order you are dealing with.

Rika Jitosho 2E

Will we be given a table of or a list standard cell potential values? While taking the 2013 winter midterm, when I got to question 8A, I wasn't sure how to get the Enot values I was wondering the same thing too! This is also the case for Question 7 in the 2013 midterm. The answer key shows the stan...

Rika Jitosho 2E

For B to C, by looking at the y-axis of the graph, the pressure decreases, so in other words, pressure is not constant. We know from class that under irreversible conditions, pressure is constant, but since that is not the case, we have to use the work equation for variable pressure (reversible work...

Rika Jitosho 2E

Chem_Mod wrote:You would earn credit, just not full credit. If it didn't explicitly ask for your answer in joules in the question, you could argue for points back. Also, were the units given in the question in joules?

The question doesn't include any units in joules, so would this affect your response? Thank you!

Rika Jitosho 2E

Does anyone know if we lose points for giving our final answer in units of kJ rather than J if when converted, they equal the same value? For instance, in the Practice Midterm from Winter 2013, Q4A shows a point breakdown of "-1pt for lack of conversion to J". Since the question didn't exp...

Rika Jitosho 2E

Okay, that's what I was thinking as well. Thank you for confirming!

Rika Jitosho 2E

Does anyone know how important is it to keep track of, and write down, the subscripts (s), (l), (aq), (g) in a reaction on our tests/quizzes? In other words, will we be penalized for not including them in our work? Thank you!

Rika Jitosho 2E

The constant sheet will be nearly identical to the one on the quiz. If anything, it may have different bond enthalpies as they pertain to each question. A periodic table will also be provided. Expect the midterm as a whole to look very similar to the last quiz. Hoped this helped! Great, thank you f...

Rika Jitosho 2E

Does anyone know how to post a new topic/question? I've been trying to figure this out and have been answering questions until now. I couldn't locate the "add post" anywhere on the page. I've even looked at the FAQs and the answer there didn't help. Please let me know; thank you! :) Hi Es...

Rika Jitosho 2E

Much like during the quiz, I know we will have the equation sheet, but does anyone know if it will be the exact same sheet as the one given for the quiz? Additionally, does anyone know if we will be given a periodic table for the midterm? Thank you!

Rika Jitosho 2E

Yes, I believe that would be correct! At the end of your calculation you would keep the negative sign since that is the correct numerical value, and then in your answer, you would interpret the negative $\Delta$ H value as the amount of heat being released from the system.

Rika Jitosho 2E

The workbooks of the practice quizzes are not turned in like those from last quarter correct? There was also a recent post about this in the Announcements thread titled "Re: Posts", and a student replied to this question saying that they believe we wouldn't be doing that this quarter. If ...

Rika Jitosho 2E

Well, in answer to your first question, I believe that my TA said that if you post more than one time per week you can get up to 2.5% extra credit this way. I'm terrified that I might be wrong though, so if anyone could confirm or deny this that would be great. Hi Kimberly, yes, I can confirm as th...

Rika Jitosho 2E

Hi Carla, It was helpful for me to remember that q p = \Delta H = enthalpy. q p gives a measure of heat released or absorbed at a constant pressure. Enthaply, or \Delta H will be negative if the system is losing heat; therefore the system is cold, and the surroundings, hot. This type of reaction wou...

Rika Jitosho 2E

Something that I don't believe has been mentioned yet are the practice exams that Dr. Lavelle provides for us. They are a fantastic resource in terms of being able to test whether or not you can apply the concepts you've studied. In Chem 14A, I found that sometimes reading and studying a concept can...

Rika Jitosho 2E

Yep! Since the shape of the ICl₃ molecule is T-shaped with 3 bonds and 2 lone pairs, we know that the ClICl bond angles are all the same, and should each be less than 90 degrees.

Rika Jitosho 2E

I just wanted to make sure--In order to write the equilibrium expression, K, for a reaction, we must first make sure the reaction is balanced, correct? For instance, in homework question 11.3b, the reaction is: 4NH 3 + 6NO = 7N 2 + 6H 2 O The answer key uses these stoichiometric coefficients for the...

Rika Jitosho 2E

I believe it's one post per week to ensure that you're getting discussion credit for that week, although I'm sure it doesn't hurt to post more than that! I was also wondering, though, if the posts must be made during the week days, or if we still get credit as long as the post is made before the nex...

Rika Jitosho 2E

Knowing that the lone pairs affect the overall shape of the compound--for instance, in H 2 0 the 2 oxygen lone pairs push the hydrogen atoms down to create the bent shape-- for any compound, can we expect that all of the bond angles affected by the repulsion of the lone pairs decrease equally? Thank...

Rika Jitosho 2E

In addition to quiz clarifications, I see the syllabus states that our exams are to be written in pen, but does anyone know if this applies to the Preparation quiz that we submit as well? Thank you!

Rika Jitosho 2E

Looking at how I solved this question, I believe that when you divided 2.00g by the molar mass 286.21 g.mol -1 , that was correct. But after that, I still multiplied that fraction by 10mol H 2 0 over 1mol Na 2 CO 3 . 10H 2 O. I put moles of H 2 O as my numerator in the second fraction because moles ...

CHEMISTRY COMMUNITY

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Re: Difference between cis and Z, and trans and E

Re: Gibbs Free Energy in Reaction Profiles

Re: Quiz 3 Winter 2017

Re: Reaction profile for SN2 reaction

Reaction profile for SN2 reaction

Re: Midterm Winter 2017

Re: Midterm Winter 2017

Re: Quiz 2 #9 and #10

Re: WHat is the unit of k

Re: Midterm- Standard Cell Potential values

Re: Winter 2013 Midterm: Question #4

Re: Units for final answers on midterm

Units for final answers on midterm

Re: Subscripts in a reaction

Subscripts in a reaction

Re: Resources provided during Midterm 1?

Re: Posts

Resources provided during Midterm 1?

Re: signs of delta H

Re: Bruincast

Re: Posts

Re: Heat Released/Absorbed [ENDORSED]

Re: Most Helpful Resource

Re: Homework #4.9 [ENDORSED]

Writing Equilibrium Expression K for a Reaction [ENDORSED]

Re: Chemistry Community Points

Re: Molecular Vs. electron [ENDORSED]

Re: Quiz Grades?

Re: Fundamentals E [ENDORSED]