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Quiz 3 Winter 2017

Posted: Thu Mar 02, 2017 10:04 pm
by Chem_Mod
Quiz 3 covers material since Quiz 2:

Kinetics (Ch 15.11 onwards, Reaction profiles, Arrhenius equation and calculating activation energies)

Thermodynamics and Kinetics of Organic Reactions (Ch 4.1 to 4.4 from Introduction to Organic Chemistry, Problems: 1-10, 23-40)

Hydrocarbons (Ch 1 from Introduction to Organic Chemistry: But read and do only the homework problems for the two sections titled: ALKANES and CYCLOALKANES)

Quiz 3 covers pages 74 to 96 in the course reader.
For the last part (Hydrocarbons) it is only the sections titled ALKANES and CYCLOALKANES in Chapter 1.

Re: Quiz 3 Winter 2017

Posted: Thu Mar 02, 2017 11:46 pm
by Sarai_Ferrer_3C
Will we be given solutions for the practice quiz #3?

Re: Quiz 3 Winter 2017

Posted: Thu Mar 02, 2017 11:55 pm
by ntyshchenko
For kinetics, what part of the book is on the quiz? Does "Reaction profiles, Arrhenius equation and calculating activation energies" mean that it is only 15.11 and 15.13, or will the rest of chapter 15 be on the quiz?

Also, just to be clear, is Catalysis on there?

Re: Quiz 3 Winter 2017

Posted: Thu Mar 02, 2017 11:59 pm
by Derek_Petrosian_3I
Sarai_Ferrer_3C wrote:Will we be given solutions for the practice quiz #3?


Yes, solutions to practice quiz #3 will be posted in a couple of days. The answers to the last quiz were posted on the Saturday before the quiz.

Re: Quiz 3 Winter 2017

Posted: Fri Mar 03, 2017 9:36 am
by Chem_Mod
See above: Kinetics (Ch 15.11 onwards)

Quiz 3 covers pages 74 to 96 in the course reader.

When Quiz 3 solutions are ready they will be posted this weekend.
Today, Friday, I give five hours of lectures.

Re: Quiz 3 Winter 2017

Posted: Fri Mar 03, 2017 10:53 am
by Katie McCombs 3G
ntyshchenko wrote:For kinetics, what part of the book is on the quiz? Does "Reaction profiles, Arrhenius equation and calculating activation energies" mean that it is only 15.11 and 15.13, or will the rest of chapter 15 be on the quiz?

Also, just to be clear, is Catalysis on there?


Catalysis is included in the pages of the coursreader listed. The quiz will cover everything after temperature and reaction rates in chapter 15 and everything we have covered since.

Re: Quiz 3 Winter 2017

Posted: Fri Mar 03, 2017 5:34 pm
by Madeline Fox 2B
Do we have to memorize all of the common names for substituent naming thats in the course reader?

Re: Quiz 3 Winter 2017

Posted: Fri Mar 03, 2017 6:40 pm
by nickrodgers
How many questions will there be on Quiz 3?

Re: Quiz 3 Winter 2017

Posted: Fri Mar 03, 2017 6:45 pm
by MariaReina_Garcia_3E
Madeline Fox 2B wrote:Do we have to memorize all of the common names for substituent naming thats in the course reader?


Another question pertaining to this. Will it be specified if we have to name the compound with the IUPAC name or the common name?

Re: Quiz 3 Winter 2017

Posted: Fri Mar 03, 2017 10:21 pm
by nicoleclarke_lec1M
Will we need to know about Alkenes for quiz 3? we didn't talk about naming them or really anything about them in class but they are in section 1.3. Also section 1.4 about Geometric isomers and section 1.5 about alkynes were not covered in the course reader. Will we need to know about all of these things? The reading above says we should read chapter 1 section 1-6 and 11, but 3-5 were not covered. Will we also need to know section 1.11, Cycloalkenes? We only discussed cycloalkanes

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 7:39 am
by Elias Ruben 1O
Are the homework problems that Chem_Mod listed in the first post the only ones we should do to prepare for the quiz?

Transition states

Posted: Sat Mar 04, 2017 8:40 am
by Belicia Tang 1B
I have a quick question regarding transition states– when drawing a transition state diagram, must you include partial charges? Thanks!

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 11:22 am
by Chem_Mod
Madeline Fox 2B wrote:Do we have to memorize all of the common names for substituent naming thats in the course reader?


Yes

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 11:24 am
by Chem_Mod
nickrodgers wrote:How many questions will there be on Quiz 3?


7 questions

Re: Transition states

Posted: Sat Mar 04, 2017 11:39 am
by Chem_Mod
Belicia Tang 1B wrote:I have a quick question regarding transition states– when drawing a transition state diagram, must you include partial charges? Thanks!


Partial charges do not have to be included in transition state structures.

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 11:47 am
by Chem_Mod
Quiz 3 covers pages 74 to 96 in the course reader.
These pages cover alkanes and cycloalkanes.

Therefore, in Chapter 1 read and do only the homework problems for the two sections titled:
ALKANES
CYCLOALKANES

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 12:29 pm
by Chem_Mod
Quiz 3 Preparation Answers

1. 4-isopropyldecane or 4-(1-methylethyl) decane

2. Draw hexane structure with ethyl and methyl both attached to carbon 3 in hexane main chain.

3. Alkenes not covered in your Quiz 3. Your Quiz 3 covers more Kinetics.

4. 4-butyl-1,2-dimethylcyclohexane

5.
What type of reaction is shown above?
ELECTROPHILIC ADDITION REACTION

How many steps are involved?
2 steps

How many transition states?
2

Which is the rate limiting step?
1st step

How many intermediates are there?
2


6. Both are nucleophiles.

7. 2,3-dichlorobutane

8. Br2 acts as an electrophile.

QUiz 3

Posted: Sat Mar 04, 2017 3:20 pm
by Tyler Miao 1A
for number 8 on Quiz 3, I'm not understanding why Br2 acts as an electrophile. Can someone explain please?

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 3:35 pm
by Sue_Park_2D
For number 1, I wrote down 4-isopropyldecane as my answer, but I don't understand why it can also be 4-(1-methleythyl) decane

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 6:05 pm
by Blake_Katsev_2E
Shouldnt number 4 be 5-butyl instead of 4-butyl?

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 6:37 pm
by Arshia_Sabir_3E
Can someone help me with #6
I don't understand how both of them are nucleophiles?

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 8:31 pm
by Alexma 3A
Can someone help me on #6, I don't understand why both are nucleophiles

Re: Quiz 3 Winter 2017

Posted: Sat Mar 04, 2017 11:09 pm
by NicoleRivas3J
Can someone just go over and explain number 5?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 2:13 am
by chris2E
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


Are you referring to #6? Nucleophiles are species rich in electrons. For the benzene ring, this electron richness comes from its double bonds. For the oxygen in the center of the compound can only be attached to each carbon by single bonds (since each carbon is already bonded to three hydrogens); thus, the oxygen must have two lone pairs of electrons in order to satisfy the octet rule.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 9:22 am
by Nancyh_1E
Blake_Katsev_2E wrote:Shouldnt number 4 be 5-butyl instead of 4-butyl?

4-butyl should be the correct answer because you’re supposed to number the carbons in the chain from the end that gives the substituents the lowest numbers. In this case, you start from the top left carbon of the cyclohexane structure and number the rest of the carbons in a counterclockwise manner. Butyl will be located on the fourth carbon.

Re: QUiz 3

Posted: Sun Mar 05, 2017 10:00 am
by Diwana Lucero 3K
Tyler Miao 1A wrote:for number 8 on Quiz 3, I'm not understanding why Br2 acts as an electrophile. Can someone explain please?

Br2 acts as an electrophile because it is the one being attacked by the ethene, which has a double bond, making it the nucleophile.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 10:35 am
by Shailyn_Moore_3C
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


The line diagram has multiple double bonds which are made up of a pi bond. These pi bonds serve as areas of high electronegativity due to their being so many localized electrons at each pi bond. This make it attracted to positively charged things so it is a nucleophile.

For CH3OCH3, Oxygen is more electronegative than carbon so it is going to pull the electrons in the bond closer to itself giving the oxygen a partial negative charge and since it partially negative it will attract positively charged things so it is a nucleophile.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 10:37 am
by Teddy_Rosenbluth
Will the quiz focus more on kinetics or organic chemistry?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 12:27 pm
by Caity Colt 2N
Blake_Katsev_2E wrote:Shouldnt number 4 be 5-butyl instead of 4-butyl?


If you start counting at the top H3C then go around counterclockwise, you should get 4-butyl.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 12:49 pm
by GregoryPolyakov_1H
Question on how many steps involved in a rxn:
Are the number of steps directly related to how many atoms are moving and/or how many bonds are broken or formed?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 1:36 pm
by Jennifer Ngo 1M
For number 7, are we expected to know what 2-butene is?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 1:52 pm
by Isabella_Pena_3D
NicoleRivas3J wrote:Can someone just go over and explain number 5?

I second this. I'm also confused on number 5

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 2:16 pm
by shreya_mantri_3I
Could someone explain number 5?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 2:58 pm
by 904621096
How do you identify pi bonds?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 3:33 pm
by haleh matinrad 1C
shreya_mantri_3I wrote:Could someone explain number 5?


It is an electrophilic addition reaction because you are adding the HBr to the cholesterol. HBr when broken up has H+ as an electrophile and Br- as a nucleophile.

There are two steps because first you add the H+ to the cholesterol then in the second step you add the Br- to the cholesterol.

There are two transition states because there are two steps.

The rate limiting step, as we know is the slow step or the one requiring the a higher activation energy. Since the first step requires the breaking of the H-Br bond and the breaking of the double bond in cholesterol, it requires more energy than the second step which is forming a bond between Br- and the C+ in cholesterol.

There are two intermediates because if you were to write out the two steps, you would have two intermediates that were formed in the first step and then used up as reactants in the second step.


Hope this all made sense!!

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:09 pm
by Jocelyn_Dao_2N
Hi! Why is the answer for number 4, 4-butyl-1,2-dimethylcyclohexane and not 1,2-dimethyl,4-butylcyclohexane?

When naming a compound, do the lower numbers do first?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:13 pm
by Michael_Phillipi_1I
For the quiz, do we need to memorize the formulas for alkanes and alkyls?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:14 pm
by Samantha Rubin-Pope - 1H
Elias Ruben 1O wrote:Are the homework problems that Chem_Mod listed in the first post the only ones we should do to prepare for the quiz?



Also make sure to take a look at the problems at the beginning of each section in the course reader! There are a variety of problems from the textbook and conceptual practice problems that will be helpful.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:16 pm
by Ariana de Souza 4C
Jocelyn_Dao_2N wrote:Hi! Why is the answer for number 4, 4-butyl-1,2-dimethylcyclohexane and not 1,2-dimethyl,4-butylcyclohexane?

When naming a compound, do the lower numbers do first?


remember that you have to do it alphabetically. butyl comes before methyl

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:17 pm
by Samantha Rubin-Pope - 1H
Will we be responsible for knowing how to solve questions 5-8 on the practice quiz #3 even though we didn't go over that kind of thing in lecture?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:19 pm
by Ariana de Souza 4C
Sue_Park_2D wrote:For number 1, I wrote down 4-isopropyldecane as my answer, but I don't understand why it can also be 4-(1-methleythyl) decane


the second answer would be if you're writing it by IUPAC rules.
you can see the isopropyl as a long ethane (that's your longest chain) with a methane coming out of the first carbon on the ethane chain. So it would be, 1-methyl-ethyl and then that whole substituent is on the fourth carbon in the longer chain, so it's 4 - (1-methyl-ethyl) decane

see the isopropyl as

C ........ C
....C......

(ignore the periods, i just wanted the spacing)
whats bolded is your longest chain in the substituent and you can see that the carbon in the first line on the left would be bonded to the carbon on the second line in the middle.
does that make sense?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:23 pm
by Michael_Phillipi_1I
Would you prefer we use common name with IUPAC or strictly IUPAC names, or does it not matter?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:24 pm
by Ariana de Souza 4C
Samantha Rubin-Pope - 1H wrote:Will we be responsible for knowing how to solve questions 5-8 on the practice quiz #3 even though we didn't go over that kind of thing in lecture?


we went through numbers 5-8 in class.. the only thing we havent is number seven when it says 2-butene. that just means you have a butene and then your double bond starts on your second carbon to your third carbon, but that reaction is an electrophilic addition reaction, which we went through in class. electrophilic addition is on pages 83--85 in the course reader, number 7's reaction has a similar one on page 82, and you can find more about electrophiles/nucleophiles in the textbook

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:27 pm
by Caitlin Dillon 3G
In class, we never discussed "electrophilic aromatic substitution," but it is in section 4.2 of the organic chem textbook. Are we expected to know this for quiz 3 and for the final?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 4:55 pm
by Jocelyn_Dao_2N
Why is the answer for number 4, 4-butyl-1,2-dimethylcyclohexane and not 1,butyl-3,4-butylcyclohexane?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 5:11 pm
by Jocelyn_Dao_2N
For the quiz, are we expected to express the compounds through the skeletal/line-angle formula or through lewis dot structure?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 6:03 pm
by Cowasjee_Sanaea_3E
For the first question, how do you know it is 4- isopropyldecane? I thought that it was just 4-propyldecane

Re: QUiz 3

Posted: Sun Mar 05, 2017 6:17 pm
by Justin_Yi_1J
Tyler Miao 1A wrote:for number 8 on Quiz 3, I'm not understanding why Br2 acts as an electrophile. Can someone explain please?


The reason Br2 can act as an electrophile is due to electron-electron repulsion. Typically, Br2 is a non-polar species. However, when it encounters the pi electrons of an alkene at a high enough energy collision, the delocalized electrons repel the valence shell of the impacting Br, generating an instantaneous dipole moment that makes the attacking Br + and therefore an electrophile.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 6:46 pm
by andrea_Disc3D
Can someone explain to me why CH3OCH3 is a nucleophile? My TA said that we should look at the center atom when determining whether a molecule is a nucleophike or electrophile. Assuming that oxygen is the central atom (?). Carbon is more electronegative than oxygen so the electrons are attracted more to the carbons. So oxygen should have a partial positive charge, right? Therefore, the molecule should an electrophile?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 7:10 pm
by andrea_Disc3D
andrea_Disc3D wrote:Can someone explain to me why CH3OCH3 is a nucleophile? My TA said that we should look at the center atom when determining whether a molecule is a nucleophike or electrophile. Assuming that oxygen is the central atom (?). Carbon is more electronegative than oxygen so the electrons are attracted more to the carbons. So oxygen should have a partial positive charge, right? Therefore, the molecule should an electrophile?


Nevermind, I was wrong. Oxygen is more electronegative than Carbon. Therefore, oxygen has a partial negative charge, thus making it a nucleophile.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 7:38 pm
by Chem_Mod
Teddy_Rosenbluth wrote:Will the quiz focus more on kinetics or organic chemistry?


As stated above: "Your Quiz 3 covers more Kinetics." Which includes kinetics of organic reactions.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 7:43 pm
by Chem_Mod
Michael_Phillipi_1I wrote:Would you prefer we use common name with IUPAC or strictly IUPAC names, or does it not matter?


As I discussed in class for IUPAC names:
For substituents in IUPAC names using either (for the substituent) are fine.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 7:52 pm
by Chem_Mod
Ariana de Souza 4C wrote:
Samantha Rubin-Pope - 1H wrote:Will we be responsible for knowing how to solve questions 5-8 on the practice quiz #3 even though we didn't go over that kind of thing in lecture?


we went through numbers 5-8 in class.. the only thing we havent is number seven when it says 2-butene. that just means you have a butene and then your double bond starts on your second carbon to your third carbon, but that reaction is an electrophilic addition reaction, which we went through in class. electrophilic addition is on pages 83--85 in the course reader, number 7's reaction has a similar one on page 82, and you can find more about electrophiles/nucleophiles in the textbook


Thank you Ariana.

Q5 is the identical cholesterol example on page 84, and I went through the entire mechanism in class drawing it on the board applying the concepts and steps we covered on pages 83 and 84.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 8:09 pm
by danny_nguyen_3C
For question number 4 would "4-butyl-1-methyl-2-methylcyclohexane" be an answer that gets full points?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 8:49 pm
by 204863791
I've been studying the textbook as well as the course reader but I can't find the section concerning the transitions.... which pages can I find them on?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 8:52 pm
by Sydney Wu 2M
Shailyn_Moore_3C wrote:
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


The line diagram has multiple double bonds which are made up of a pi bond. These pi bonds serve as areas of high electronegativity due to their being so many localized electrons at each pi bond. This make it attracted to positively charged things so it is a nucleophile.

For CH3OCH3, Oxygen is more electronegative than carbon so it is going to pull the electrons in the bond closer to itself giving the oxygen a partial negative charge and since it partially negative it will attract positively charged things so it is a nucleophile.


Isn't the formal charge on each carbon for the first compound +1, making it an electrophile?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 9:37 pm
by Martha Xuncax 3G
^Yes, I thought that too. Can someone explain this?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 10:14 pm
by Alex Yee - 4I
I guess I should really try to be prepared for anything, but how much of the quiz 2 kinetics material will be necessary to work with the kinetics material on quiz 3? I know we won't be tested on quiz 2 material unless it is used to answer a quiz 3 question, but how much of quiz 2 do we need to know for this?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 10:32 pm
by Katelyn_Nakamura_1B
If we are asked to write out the name of a structure, do we have to do the italicizing thing and would we lose points if we forget the dash or we accidentally add a space in between the words (ethyl butane vs ethylbutane etc.)? I know these are minor questions but still I'm curious.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 10:55 pm
by Alysha Jackson 2A
When studying, should we focus specifically on the standard gibbs free energy reaction profile or all of the reaction profiles?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:15 pm
by sun_emily 2D
Are we supposed to memorize the structures of functional groups in both IUPAC names and the shorter ones?

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:24 pm
by Chem_Mod
904621096 wrote:How do you identify pi bonds?


Whenever there is a double or triple bond.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:27 pm
by Chem_Mod
Caitlin Dillon 3G wrote:In class, we never discussed "electrophilic aromatic substitution," but it is in section 4.2 of the organic chem textbook. Are we expected to know this for quiz 3 and for the final?


No, because we are not covering it. It is part of Chem 14C Syllabus.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:28 pm
by Chem_Mod
Jocelyn_Dao_2N wrote:For the quiz, are we expected to express the compounds through the skeletal/line-angle formula or through lewis dot structure?


Both are expected in Chem 14B.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:30 pm
by Chem_Mod
GregoryPolyakov_1H wrote:Question on how many steps involved in a rxn:
Are the number of steps directly related to how many atoms are moving and/or how many bonds are broken or formed?


They are unrelated.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:32 pm
by Chem_Mod
Jennifer Ngo 1M wrote:For number 7, are we expected to know what 2-butene is?


Yes. I went through the electrophilic addition of HBr to 2-butene three times in class - spent an entire lecture on this reaction with 2-butene.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:36 pm
by Chem_Mod
Katelyn_Nakamura_1B wrote:If we are asked to write out the name of a structure, do we have to do the italicizing thing and would we lose points if we forget the dash or we accidentally add a space in between the words (ethyl butane vs ethylbutane etc.)? I know these are minor questions but still I'm curious.


Full credit given for all these minor differences.

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:37 pm
by Chem_Mod
Alysha Jackson 2A wrote:When studying, should we focus specifically on the standard gibbs free energy reaction profile or all of the reaction profiles?


For organic reactions: standard gibbs free energy reaction profile

Re: Quiz 3 Winter 2017

Posted: Sun Mar 05, 2017 11:40 pm
by Chem_Mod
sun_emily 2D wrote:Are we supposed to memorize the structures of functional groups in both IUPAC names and the shorter ones?


Yes. But you meant: "the structures of substituents in both IUPAC names and the shorter ones"
I covered them in class and you will see them in Chem 14C, Chem 14CL, and Chem 14D. Faculty teaching these organic classes tell me my students are the best prepared! Same for the MCAT, etc.

As I announced in class Quiz 3 does not cover functional groups.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 12:14 am
by Alexis Elliott 1J
chris2E wrote:
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


Are you referring to #6? Nucleophiles are species rich in electrons. For the benzene ring, this electron richness comes from its double bonds. For the oxygen in the center of the compound can only be attached to each carbon by single bonds (since each carbon is already bonded to three hydrogens); thus, the oxygen must have two lone pairs of electrons in order to satisfy the octet rule.


If the Oxygen is in the center though can't it polarize the bonds to make the Carbons delta positive, thereby making it an electrophile?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 3:06 am
by Thomas Hui 2J
Do we have to know Electrophilic Aromatic Substitution and Bimolecular Nucleophilic Substitution?

Follow up question:
Is Bimolecular Nucleophilic Substitution the same thing as Nucleophilic Substitution?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:43 am
by Chem_Mod
Alexis Elliott 1J wrote:
chris2E wrote:
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


Are you referring to #6? Nucleophiles are species rich in electrons. For the benzene ring, this electron richness comes from its double bonds. For the oxygen in the center of the compound can only be attached to each carbon by single bonds (since each carbon is already bonded to three hydrogens); thus, the oxygen must have two lone pairs of electrons in order to satisfy the octet rule.


If the Oxygen is in the center though can't it polarize the bonds to make the Carbons delta positive, thereby making it an electrophile?


I will go through this in detail in class today (Monday March 6).

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:46 am
by Chem_Mod
Thomas Hui 2J wrote:Do we have to know Electrophilic Aromatic Substitution and Bimolecular Nucleophilic Substitution?

Follow up question:
Is Bimolecular Nucleophilic Substitution the same thing as Nucleophilic Substitution?


We did not cover Electrophilic Aromatic Substitution.

We did cover Bimolecular Nucleophilic Substitution (SN2). See lecture notes.

Bimolecular Nucleophilic Substitution is one type of Nucleophilic Substitution.
The only nucleophilic substitution we have done is Bimolecular Nucleophilic Substitution (SN2). See lecture notes.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 4:02 pm
by Morgan_McMasters_3A
In the organic chemistry text book, there are several assigned homework problems that have to do with identifying and naming alkenes and cycloalkenes. 1.25-1.29 ask to name this alkene or draw a structure of (Z)-3-methyl-3-heptene. I thought the quiz was only over alkanes and cycloalkanes but is there a chance that these kinds of questions will be on the quiz because they were assigned?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 4:20 pm
by danny_nguyen_3C
Are we required to know reaction mechanisms for the quiz?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 4:22 pm
by Christian_Makar_2D
danny_nguyen_3C wrote:Are we required to know reaction mechanisms for the quiz?

If by section mechanisms you mean where we split up for example an electrophilic addition reaction into two steps and draw arrows representing where the electrons are going, then yes you must know them.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 6:13 pm
by Jordan Pace 2B
In response to, "Why is the answer for #4, 4-butyl-1,2-dimethylcyclohexane and not 1,2-dimethyl,4-butylcyclohexane? When naming a compound, do the lower numbers go first?"

You list different substituents alphabetically, not based on the numbers. In this example, butyl comes before methyl because b comes before m.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 6:54 pm
by Claire_Zhou_1A
For question #8, what does the forth statement mean by "the Br- ion attacks at the same face of the bromonium ion"? Is it trying to say that the Br- attacks the same carbon attached by another Br?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 7:47 pm
by Priscilla_Covarrubias_HL
For #6 in the quiz prep, both are nucleophiles, so how would an electrophile look like? Would it be a molecule that wants more electrons to be complete?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 8:08 pm
by Leo_Navejas_3B
For #4 Why isn't it 1-butyl-3,4 dimethylcyclohexane?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 8:13 pm
by Katie_Ho_1M
Would you ever use use neo- in IUPAC naming? If so, when and how? (please give an example)

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 8:20 pm
by Carla Cruz Medina 1L
Will we be tested in systematic names for quiz 3?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 8:22 pm
by Alice Jung 1C
Can somebody please clarify what compound is named in #1 please for the practice quiz 3? The print on my CR is very faint.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 9:15 pm
by angelicapayne
Alice Jung 1C wrote:Can somebody please clarify what compound is named in #1 please for the practice quiz 3? The print on my CR is very faint.


It is: CH3 CH2 CH2 CH2 CH2 CH2 CH (off of this C there is CH(CH3)2) CH2 CH2 CH3
So there are 10 carbons on the main chain and CH(CH3)2 is the substituent off the 7th C

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 9:16 pm
by Julia Hwang 3G
Morgan_McMasters_3A wrote:In the organic chemistry text book, there are several assigned homework problems that have to do with identifying and naming alkenes and cycloalkenes. 1.25-1.29 ask to name this alkene or draw a structure of (Z)-3-methyl-3-heptene. I thought the quiz was only over alkanes and cycloalkanes but is there a chance that these kinds of questions will be on the quiz because they were assigned?

Dr. Lavelle posted an announcement on chem community that said we should only read and do the homework problems of chapter 1 pertaining to alkanes and cycloalkanes for quiz 3.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 9:28 pm
by Jennifer Ngo 1M
Leo_Navejas_3B wrote:For #4 Why isn't it 1-butyl-3,4 dimethylcyclohexane?

Page 96 in the course reader should help.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 9:38 pm
by Chem_Mod
Katie_Ho_1M wrote:Would you ever use use neo- in IUPAC naming? If so, when and how? (please give an example)


neopentylcyclohexane

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 9:41 pm
by Chem_Mod
Priscilla_Covarrubias_HL wrote:For #6 in the quiz prep, both are nucleophiles, so how would an electrophile look like? Would it be a molecule that wants more electrons to be complete?


Correct, electrophiles are electrostatically attracted to electron rich species and regions. See pages 81 and 82 in the course reader and more examples in the organic textbook.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 9:42 pm
by Chem_Mod
Carla Cruz Medina 1L wrote:Will we be tested in systematic names for quiz 3?


Definitely

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:04 pm
by ntruong2H
When writing rate laws do we have to include the charges? like [CH3C+CH3] and [Br-]?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:32 pm
by Simone Seliger 1C
chris2E wrote:
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


Are you referring to #6? Nucleophiles are species rich in electrons. For the benzene ring, this electron richness comes from its double bonds. For the oxygen in the center of the compound can only be attached to each carbon by single bonds (since each carbon is already bonded to three hydrogens); thus, the oxygen must have two lone pairs of electrons in order to satisfy the octet rule.



Does this mean that a nucleophile can be identified as having lone pairs (in its Lewis structure)?

And furthermore, is the reason that the benzene ring is a nucleophile because its double bonds have the ability to become a single bond and a lone pair? Therefore giving the structure lone pairs and making it a nucleophile?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:35 pm
by emilie liu 3G
Will we have to know tert and sec for the quiz or can we use the IUPAC names for them instead of common names?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:36 pm
by Camila Sanabria 1B
When drawing reaction profiles for the Quiz will we be deducted points for writing the words "reactants", "intermediates" , "products"? Or do we have to write the actual molecules for reactants, intermediates, and products in order to get full credit?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:41 pm
by Ariana de Souza 4C
Simone Seliger 1C wrote:
chris2E wrote:
Arshia_Sabir_3E wrote:Can someone help me with #3
I don't understand how both of them are nucleophiles?


Are you referring to #6? Nucleophiles are species rich in electrons. For the benzene ring, this electron richness comes from its double bonds. For the oxygen in the center of the compound can only be attached to each carbon by single bonds (since each carbon is already bonded to three hydrogens); thus, the oxygen must have two lone pairs of electrons in order to satisfy the octet rule.



Does this mean that a nucleophile can be identified as having lone pairs (in its Lewis structure)?

And furthermore, is the reason that the benzene ring is a nucleophile because its double bonds have the ability to become a single bond and a lone pair? Therefore giving the structure lone pairs and making it a nucleophile?


The reason that benzene is a nucleophile is because nucleophiles are identified by having an excess, or large amount, of electrons. Double bonds on the benzene ring attract compounds with a positive charge, so it is considered a nucleophile, since the "loosely bound pi electrons in double and triple bonds are more likely to be involved in a reaction as a nucleophile" (page 145, o-chem textbook). However, nucleophiles can sometimes be neutral, but mostly they will have lone pairs.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:43 pm
by Tatum_Bernat_1E
Cowasjee_Sanaea_3E wrote:For the first question, how do you know it is 4- isopropyldecane? I thought that it was just 4-propyldecane



Can someone please address this? Why do we need the "iso" prefix? Isn't it just a propyl functional group attached to the 4th carbon of a decane compound?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:46 pm
by Ariana de Souza 4C
Tatum_Bernat_1E wrote:
Cowasjee_Sanaea_3E wrote:For the first question, how do you know it is 4- isopropyldecane? I thought that it was just 4-propyldecane



Can someone please address this? Why do we need the "iso" prefix? Isn't it just a propyl functional group attached to the 4th carbon of a decane compound?


The reason we can't just say it's a propyl is because, if you draw out the substituent CH(CH3)2 you'll see that it has to be structured like an iso group -- that branching type. A propyl substituent would have only one CH3 -- at the end of the branch. This, however, has two CH3's, which means it's iso. That specific structure is why we need to specify "isopropyl" and not just "propyl"

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 10:59 pm
by Tyler_Ash_3C
Leo_Navejas_3B wrote:For #4 Why isn't it 1-butyl-3,4 dimethylcyclohexane?

For cycloalkanes with more than two substituents, you must compare each individual number for each substituent:

1-butyl-3,4-dimethylcyclohexane (incorrect)
4-butyl-1,2-dimethylcyclohexane (correct)

Since your proposed answer has 1,3,4 while the correct answer has 1,2,4, the second answer is correct because 2 is less than 3. The lowest number in each case is one, but the second answer has a lower second number (2) than the first answer (3), so the second answer is correct.

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 11:11 pm
by Teddy_Rosenbluth
Would vinyls be considered functional groups and therefor we don't need to know it for Quiz 3?

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 11:18 pm
by Julie Barreto 3A
how would you draw out 2-butene or anything with a number in front of it ???

Re: Quiz 3 Winter 2017

Posted: Mon Mar 06, 2017 11:49 pm
by 304751905
for #1, why do we need "iso" in front of propyl? wouldn't the 4- signify the branching?