Search found 174 matches

by 704278444
Sun Mar 16, 2014 1:34 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: organic chem textbook p.17
Replies: 4
Views: 652

Re: organic chem textbook p.17

but don't you look at the atoms on two sides of the double bond? (instead of looking at atoms that are so far apart?)
by 704278444
Sun Mar 16, 2014 12:20 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: organic chem textbook p.17
Replies: 4
Views: 652

organic chem textbook p.17

why is the left fourth molecule (E- 3,7-Dimethylocta-1.3.7-triene) trans and the right fourth molecule (Z-3.7-Dimethylocata-1,3,7-triene) cis? Can you explain in detail?
by 704278444
Sun Mar 16, 2014 11:39 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: final 2012 1b
Replies: 8
Views: 1029

Re: final 2012 1b

you can say that, if you have the q for the reaction at lower temp. (like this particular example)
So if you know the q for the reaction at higher temp instead, you would want to heat your reaction, then cool it. and combine the three values you get to find the q for your reaction at desired temp.
by 704278444
Sat Mar 15, 2014 9:56 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: 2013 Q8C
Replies: 1
Views: 453

2013 Q8C

Question 8C on Winter 2013 Final Exam states:

"Name the molecule shown in the Newman projection below? What conformation is it in?"


How do you know this is a chair conformation by looking at newman projection?
by 704278444
Sat Mar 15, 2014 9:47 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: 2012 Q8A
Replies: 2
Views: 661

2012 Q8A

Question 8A on the Winter 2012 Final Exam states:

"Draw a Newman projection of 1 -iodopropane looking down the C1-C2 bond with a dihedral angle of +120 degrees for the ICCC dihedral angle."

How do you know this is an eclipsed conformation?
by 704278444
Sat Mar 15, 2014 9:43 pm
Forum: *Alkanes
Topic: 2012 final Q6B last subquestion
Replies: 2
Views: 1400

2012 final Q6B last subquestion

How do you figure the name of this molecule out by looking its structural formula: (CH3CH2CH2)4C ?
by 704278444
Sat Mar 15, 2014 9:41 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 2011 2
Replies: 3
Views: 589

Re: 2011 2

Because you are combining two reactions. you want the H2 to cancel out.
by 704278444
Sat Mar 15, 2014 9:38 pm
Forum: *Organic Reaction Mechanisms in General
Topic: 2012 final Q5
Replies: 1
Views: 519

2012 final Q5

In molecule B, step 2, why is that O connecting to OH giving more e- the double bond? Isn't the double bond already e- riched itself?
by 704278444
Sat Mar 15, 2014 9:34 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2012 final Q3 (c)
Replies: 2
Views: 430

2012 final Q3 (c)

When we write the cell diagram for this cell, why do we need to put molarity?
can we write like this instead?
Cr (s)|Cr+ (aq) || Cu+ (aq)| Cu (s)
by 704278444
Sat Mar 15, 2014 9:31 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: final 2012 1b
Replies: 8
Views: 1029

Re: final 2012 1b

and why are we calculating these three paths? how do you know?
by 704278444
Sat Mar 15, 2014 8:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Quiz 1 Prep 2013 #9
Replies: 2
Views: 1226

Re: Quiz 1 Prep 2013 #9

the gas molecules are in "rigid, insulated box", indicating that the volume is constant.
by 704278444
Sat Mar 15, 2014 8:53 pm
Forum: *Alcohols
Topic: 2.40 c
Replies: 2
Views: 539

Re: 2.40 c

I don't have the organic textbook with me now. can you post the question?
by 704278444
Sat Mar 15, 2014 8:51 pm
Forum: *Cycloalkanes
Topic: 2012 Final Q6B
Replies: 3
Views: 676

Re: 2012 Final Q6B

can you clarify your question?
by 704278444
Sat Mar 15, 2014 8:32 pm
Forum: *Alkanes
Topic: Drawing structures in general for the final
Replies: 5
Views: 822

Re: Drawing structures in general for the final

Usually you don't need to draw H for line structure. Hs are there just for clarification.
by 704278444
Sat Mar 15, 2014 8:30 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Final 2011, 1C
Replies: 3
Views: 685

Re: Final 2011, 1C

ethane have a higher heat capacity than ethene because a double bond is stronger than a triple bond, so it requires more energy to break a double bond NO has a greater residual entropy at 0 K than BF3 because BF3 is is symmetrical while NO is not. NO also has resonance which gives rise to more micro...
by 704278444
Sat Mar 15, 2014 7:56 pm
Forum: General Rate Laws
Topic: 2011 final Q4A (a)
Replies: 2
Views: 554

Re: 2011 final Q4A (a)

i still don't get why it is raised to the nth power
can someone clarify?
by 704278444
Sat Mar 15, 2014 7:47 pm
Forum: *Alkenes
Topic: 2009 final Q7D
Replies: 4
Views: 659

Re: 2009 final Q7D

on the top carbon, why is it not CH2 vs CH3 but CH2 vs H?
by 704278444
Sat Mar 15, 2014 6:54 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: anti
Replies: 3
Views: 670

Re: anti

but why in the calculation we always plug in zero for anti?
by 704278444
Sat Mar 15, 2014 6:45 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: final 2007 Q6A
Replies: 5
Views: 983

Re: final 2007 Q6A

Is C correct?
because D is more like delta G and delta H:
D: is related to the difference in energy between the starting materials and the products.
by 704278444
Sat Mar 15, 2014 6:39 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: anti
Replies: 3
Views: 670

anti

does anti always give an energy of zero?
by 704278444
Sat Mar 15, 2014 6:16 pm
Forum: *Alkanes
Topic: Sec vs. Iso
Replies: 3
Views: 647

Re: Sec vs. Iso

viewtopic.php?f=97&t=3849
by 704278444
Sat Mar 15, 2014 6:14 pm
Forum: *Alkanes
Topic: Sec vs. Iso
Replies: 3
Views: 647

Re: Sec vs. Iso

for sec, the carbon connecting to the main chain are secondary carbon.
for iso, the carbon connecting to the main chain is primary
by 704278444
Sat Mar 15, 2014 4:43 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: final 2007 Q6A
Replies: 5
Views: 983

final 2007 Q6A

I tried to fill in words for all the definitions, and I couldn't figure out some of them. Can someone help me with them? B. is that the transition state for an endothermic reaction will resemble the product C. is the difference in energy between the starting materials and the products E. describes t...
by 704278444
Fri Mar 14, 2014 9:17 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: sec vs iso
Replies: 2
Views: 681

sec vs iso

what is the difference between sec and iso?
by 704278444
Fri Mar 14, 2014 7:51 pm
Forum: General Science Questions
Topic: sig fig
Replies: 1
Views: 909

sig fig

in 2007 final Q1A,
why is there 3 sig fig for the final answer?
don't we have 30. degree celsius in the question? (which is two sig fig)
so shouldn't we keep our answer to 2 sig fig?
by 704278444
Fri Mar 14, 2014 11:09 am
Forum: *Organic Reaction Mechanisms in General
Topic: substitution reaction
Replies: 4
Views: 789

Re: substitution reaction

however, I still have difficulty understanding what SN2 is. Can someone explain it to me?
by 704278444
Fri Mar 14, 2014 11:04 am
Forum: *Organic Reaction Mechanisms in General
Topic: 2013 final Q5C
Replies: 1
Views: 474

2013 final Q5C

Near the bottom of the page,
how do you know that it's trigonal bipyramidal geometry?
by 704278444
Fri Mar 14, 2014 11:03 am
Forum: Administrative Questions and Class Announcements
Topic: Link to Dr. Lavelle's review session 2014
Replies: 3
Views: 1089

Re: Link to Dr. Lavelle's review session 2014

the link you just posted works!! :) thanks
by 704278444
Fri Mar 14, 2014 10:53 am
Forum: *Organic Reaction Mechanisms in General
Topic: substitution reaction
Replies: 4
Views: 789

substitution reaction

2013 final Q5C
This reaction is a substitution reaction. But I am not quite sure which atom is substituting which atom?
and what is a "SN2" reaction? The answer key says that if we only indicate it's a substitution reaction we would only get half credit.
by 704278444
Fri Mar 14, 2014 10:47 am
Forum: *Alkanes
Topic: Newman projection
Replies: 3
Views: 597

Re: Newman projection

where do you start numbering? from the top? from the middle carbon? and which direction do you continue numbering?
by 704278444
Fri Mar 14, 2014 10:46 am
Forum: Administrative Questions and Class Announcements
Topic: Link to Dr. Lavelle's review session 2014
Replies: 3
Views: 1089

Link to Dr. Lavelle's review session 2014

I couldn't open the link to Dr. Lavelle's review session. Is it my laptop or is it a connection problem? Can anyone else open it?
by 704278444
Thu Mar 13, 2014 11:30 pm
Forum: *Alkanes
Topic: Newman projection
Replies: 3
Views: 597

Newman projection

In a newman projection, from where do you start numbering? does it start in the middle C of the newman projection? Or does it matter? and how do you number the rest? I know that we don't need to number the carbons in a newman projection, but I just want to know how to count them so I can know where ...
by 704278444
Thu Mar 13, 2014 11:20 pm
Forum: General Rate Laws
Topic: 2011 final Q4A (a)
Replies: 2
Views: 554

2011 final Q4A (a)

how do you determine the rate law for this reaction based on the integrated rate law? Why is [A] raised to the nth power?
by 704278444
Thu Mar 13, 2014 11:14 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 2011 final Q3D
Replies: 1
Views: 449

2011 final Q3D

The question is: Under what conditions is the maximum work of a battery always equal to delta G?
answer: Wmax = delta G only when temperature and pressure are constant.
Why is that?
by 704278444
Thu Mar 13, 2014 11:09 pm
Forum: *Alkenes
Topic: benzene
Replies: 1
Views: 443

benzene

Are we responsible for knowing benzene on the final? Benzene appears in 2011 final Q2.
by 704278444
Thu Mar 13, 2014 11:07 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 2011 Q1C
Replies: 4
Views: 1076

2011 Q1C

How do you tell which has greater residual entropy? (in this case NO and BF3)
by 704278444
Thu Mar 13, 2014 11:04 pm
Forum: Calculating Work of Expansion
Topic: 2011 final Q1B
Replies: 1
Views: 380

2011 final Q1B

why is the change mole of gas -2.00? where did that come from?
by 704278444
Thu Mar 13, 2014 10:38 pm
Forum: *Alkenes
Topic: 2009 final Q7D
Replies: 4
Views: 659

2009 final Q7D

Question 7D on the Winter 2009 Final Exam states:

"Name the molecule." It features a trans alkene with various substituents.


How do you know this molecule is trans? can someone explain to me in detail?
by 704278444
Thu Mar 13, 2014 10:34 pm
Forum: *Cycloalkenes
Topic: Final 2012 Q5: configuration of a cyclooctenone
Replies: 6
Views: 1221

Re: Final 2012 Q5

You also determine whether a molecule is cis or trans by looking at the bonds beside the double bonds. In molecule B, you see that both sides of the double bonds have atom on the same side, thus, it is cis.
by 704278444
Thu Mar 13, 2014 6:03 pm
Forum: *Alkenes
Topic: 2007 final Q7(b)
Replies: 2
Views: 499

Re: 2007 final Q7(b)

got it! thank you so much! (and yes i meant (a))
by 704278444
Thu Mar 13, 2014 5:46 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2008 finalQ3D
Replies: 3
Views: 514

2008 finalQ3D

The second to the last step of this question: E= 0.34-(0.0592/2)*log(1/(1*10^-16))
How did you plug in numbers for logQ? how did you get that?
by 704278444
Thu Mar 13, 2014 5:31 pm
Forum: *Alkenes
Topic: 2007 final Q7(b)
Replies: 2
Views: 499

2007 final Q7(b)

Question 7B on the Winter 2007 Final Exam states: "Name the following molecules." The second molecule (part b) features a cyclohexane in a chair conformation with substituents on the 1st and 2nd carbon. For this molecule, Why do you start numbering from the bottom? If we want the lowest nu...
by 704278444
Thu Mar 13, 2014 5:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 2010 final 1b
Replies: 6
Views: 802

Re: 2010 final 1b

How do you know how much heat is required to break 1 mole of butane gas? where can you find it?
(In this question it asks us to compare the heat require to heat 1 mole H2 or 1 mole of butane gas)
by 704278444
Thu Mar 13, 2014 4:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2012 final Q3 (a)
Replies: 3
Views: 623

2012 final Q3 (a)

The answer gives that the chrome-plated piece of metal is the anode in 200mL of 0.0080M CrCl3(aq) in one of the 250 mL beakers and the copper wire is the cathode in 200mL of 0.12M CuSO4(aq) in the other beaker. How do you know which one is cathode and which one is anode? Do you refer to their standa...
by 704278444
Tue Mar 11, 2014 11:42 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final 2008 3.
Replies: 7
Views: 819

Re: final 2008 3.

Is Pb the anode because it is solid? So can we conclude that a solid always serve as an anode?
by 704278444
Tue Mar 11, 2014 11:36 am
Forum: Phase Changes & Related Calculations
Topic: 2010 Final Question 1A
Replies: 3
Views: 423

Re: 2010 Final Question 1A

It is given in the cover sheet.
by 704278444
Tue Mar 11, 2014 11:34 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2010 final Q4A
Replies: 1
Views: 316

2010 final Q4A

The answer key explains that "in a buffer system (A) approximately equals to (HA)."
Why? and what does (A) stand for? What does (HA) stand for?
by 704278444
Tue Mar 11, 2014 11:28 am
Forum: Phase Changes & Related Calculations
Topic: 2010 final Q1B
Replies: 1
Views: 335

2010 final Q1B

How are you supposed to know heating up what requires more heat? Shouldn't a chart of specific heat be given?
How do you know which one requires more heat for each three subquestion in this problem?
by 704278444
Tue Mar 11, 2014 11:10 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 2010 final Q1A
Replies: 1
Views: 318

2010 final Q1A

When the answer key is calculating q1 for warming up the ice, it plugs in 10 degree Celsius directly for temperature. But shouldn't it convert the temperature to 293K first?
by 704278444
Tue Mar 11, 2014 11:07 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: 2009 final Q6C
Replies: 3
Views: 637

Re: 2009 final Q6C

and What would trans for this specific molecule be like?
by 704278444
Tue Mar 11, 2014 11:06 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: 2009 final Q6C
Replies: 3
Views: 637

2009 final Q6C

Question 6C on the Winter 2009 Final Exam states:

"Name this molecule." The question features a cyclopentane molecule with an OH group on the 1st carbon and a Cl on the 2nd carbon.


How can you tell that this molecule is cis?
by 704278444
Tue Mar 11, 2014 11:05 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2009 final question 4C
Replies: 3
Views: 529

Re: 2009 final question 4C

Where did you find out that it is 1.00M? Is it from the 1.00M HClO4?
by 704278444
Tue Mar 11, 2014 11:03 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2008 final Q3C
Replies: 1
Views: 303

2008 final Q3C

The question is: When Na2S solution is added to the Pb^2+ electrolyte, solid PbS forms. What happens to the cell voltage (does it increases or decreases)? The answer is increase.
How do you tell?
by 704278444
Tue Mar 11, 2014 11:01 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2008 final Q3B
Replies: 1
Views: 381

2008 final Q3B

What does the question mean?
Isn't Pb/Pb^2+ anode and Cu/Cu^2+ cathode?
by 704278444
Tue Mar 11, 2014 10:53 am
Forum: *Calculations Using ΔG° = -RT ln K
Topic: intro to OC p.109 Self-test 3.3B (c)
Replies: 1
Views: 786

intro to OC p.109 Self-test 3.3B (c)

The question asks: At a research seminar you hear a conversation about nanotechnology and the possibility of using the different rotational states of simple molecules to act like motors. if a butane-like molecule were to be used, would such a molecular motor be feasible at room temperature? The answ...
by 704278444
Tue Mar 11, 2014 10:49 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Knowing specific structure (such as benzene)
Replies: 1
Views: 313

Re: Knowing specific structure (such as benzene)

I don't think we are responsible for benzene on the final.
by 704278444
Mon Mar 10, 2014 10:14 am
Forum: *Organic Reaction Mechanisms in General
Topic: 2009 final Q6A (m) and (n)
Replies: 1
Views: 444

2009 final Q6A (m) and (n)

Can you equate these two statements?:
Reactions that are kinetically controlled= reactions that are less likely to occur at room temperature
by 704278444
Mon Mar 10, 2014 9:35 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2009 final question 4C
Replies: 3
Views: 529

2009 final question 4C

When we are calculating Q for this question, why do we ignore the concentration of [H+]^8 ?
by 704278444
Sat Mar 08, 2014 10:28 pm
Forum: *Alkenes
Topic: textbook p.100 question 2.47
Replies: 1
Views: 447

textbook p.100 question 2.47

Why is alkene included as a functional group in this question yet it is not included in question 2.46?
by 704278444
Sat Mar 08, 2014 10:24 pm
Forum: *Ketones
Topic: p.61 Pentan-2-one
Replies: 2
Views: 606

Re: p.61 Pentan-2-one

oh i got it! thank you so much!
by 704278444
Sat Mar 08, 2014 10:16 pm
Forum: *Amines
Topic: textbook p.98 question 2.35
Replies: 2
Views: 648

textbook p.98 question 2.35

Can someone please guide me through naming this compound "N-ethyl-N-methylpropan-1-amine"?
Thank you!!
by 704278444
Sat Mar 08, 2014 10:13 pm
Forum: *Ketones
Topic: p.61 Pentan-2-one
Replies: 2
Views: 606

p.61 Pentan-2-one

In the textbook p.61, for the third molecule "Pentan-2-one", why do you need a "2" to indicate the position of the ketone yet you don't need to include a "2" on the previous example "Butanone"? Isn't the ketone also on the second carbon of that molecule? Thanks!
by 704278444
Sat Mar 08, 2014 10:09 pm
Forum: *Ketones
Topic: p. 61: Butanone
Replies: 2
Views: 578

p. 61: Butanone

The second molecule Butanone on p.61 has its name in parenthesis as "Methyl ethyl ketone"
Shouldn't it be "ethyl methyl ketone" instead in order to follow the alphabetical rule? Thank you!
by 704278444
Sat Mar 08, 2014 10:07 pm
Forum: *Alkenes
Topic: benzene
Replies: 6
Views: 785

benzene

when do you include "benzene" in the name of a molecule? For example, on p.51, some cycloalkenes are named as ...cyclohexene... while some are named as ...benzene.
When do you use which? or does it not matter?

Thanks!
by 704278444
Sat Mar 08, 2014 10:03 pm
Forum: *Alkenes
Topic: intro to OC Self-Test 2.1B (b)
Replies: 1
Views: 362

intro to OC Self-Test 2.1B (b)

What is the answer for Self Test 2.1B (b) on page 50? The question asks for the molecular formula yet the answer in the back doesn't give molecular formula.
by 704278444
Tue Mar 04, 2014 8:34 pm
Forum: *Alkanes
Topic: Introduction to Organic Chemistry 1.13a
Replies: 1
Views: 297

Re: Introduction to Organic Chemistry 1.13a

Sorry my bad
It is correct
by 704278444
Tue Mar 04, 2014 8:31 pm
Forum: *Alkanes
Topic: Introduction to Organic Chemistry 1.13a
Replies: 1
Views: 297

Introduction to Organic Chemistry 1.13a

Is the answer on the back of the textbook correct for question 1.13a?
by 704278444
Tue Mar 04, 2014 7:32 pm
Forum: *Alkanes
Topic: Naming in general
Replies: 3
Views: 451

Naming in general

When you are naming molecules, the main chain or root, is always put at the last of the name right? The substituents are always put in front?
by 704278444
Sun Mar 02, 2014 8:22 pm
Forum: *Organic Reaction Mechanisms in General
Topic: text book p.156
Replies: 1
Views: 597

text book p.156

In the Introduction to Organic Chemistry textbook p. 156 near the middle: what is that line "Priority: Nu > CH2CH3> CH3> H" ?
What priority? and how do you determine?
by 704278444
Sun Mar 02, 2014 8:19 pm
Forum: *Alkenes
Topic: self-test 1.5A (b)
Replies: 10
Views: 1163

self-test 1.5A (b)

write the structural formula for 2-methyl-2-butene:
Answer: (CH3)2CCHCH3
Do you not need to draw a double bond between the CC?
Do you usually need to include notation of double bond or triple bond when you are writing structural formulas?
by 704278444
Sun Mar 02, 2014 8:07 pm
Forum: *Cycloalkanes
Topic: 2-isopropyl-1,1-dimethyl-cyclopentane
Replies: 5
Views: 884

Re: 2-isopropyl-1,1-dimethyl-cyclopentane

Just to clarify: So "2-isopropyl-1,1-dimethyl- is better than 1-isopropyl-2,2-dimethyl-. The former naming gives the lowest number overall" because when comparing those two, 2 and 2 cancel, 1 and 1 cancel, you are left with 1 and 2. Thus choose the one with the lowest number:1, in this cas...
by 704278444
Sun Mar 02, 2014 7:17 pm
Forum: *Cycloalkenes
Topic: what exactly is meant by "aryl carbocation"?
Replies: 6
Views: 900

Re: what exactly is meant by "aryl carbocation"?

Sorry but what is an aromatic ring again?
Thanks!
by 704278444
Sat Mar 01, 2014 1:13 pm
Forum: *Nucleophiles
Topic: Identifying the ambident nucleophile
Replies: 2
Views: 1226

Identifying the ambident nucleophile

I know that ambident nucleophiles can act as an electron source via different atoms because they have lone pairs available on different atoms. Why is CN- an ambident nucleophile?
Thank you
by 704278444
Thu Feb 27, 2014 6:52 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Unique reaction rate vs reaction rate
Replies: 3
Views: 799

Re: Unique reaction rate vs reaction rate

Yes you are correct. The reaction rate of a molecule is equal to its unique reaction rate. You can ignore the coefficients (number of moles) when you are calculating an average reaction rate. (see textbook example 14.1)
by 704278444
Thu Feb 27, 2014 6:49 am
Forum: General Rate Laws
Topic: Question about k when writing rate laws.
Replies: 1
Views: 332

Re: Question about k when writing rate laws.

when a question is asking for rate law, we can always just put k. unless it asks for the value of k specifically.
by 704278444
Thu Feb 27, 2014 6:47 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetic Data
Replies: 2
Views: 1967

Re: Kinetic Data

Because it means that you have a large amount of reactants and H2O will not be that much excessive comparing to sucrose; thus it won't play that big of a role anymore. meaning: it is not longer diluted.
by 704278444
Tue Feb 25, 2014 11:26 pm
Forum: General Rate Laws
Topic: writing rate law
Replies: 1
Views: 332

writing rate law

When we are writing a rate law, we write it base on the rate limiting step, not base on the overall reaction right?
by 704278444
Tue Feb 25, 2014 10:32 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: rate constant
Replies: 1
Views: 550

rate constant

why is this statement false?
"The rate constant changes as a function of reactant concentration."
What does rate constant depends on? temperature and energy barrier?
by 704278444
Mon Feb 24, 2014 7:35 pm
Forum: First Order Reactions
Topic: Derivation of Integrated Rate Law
Replies: 2
Views: 538

Re: Derivation of Integrated Rate Law

So the coefficient does not matter in real life situation. Then do we include the coefficient in our calculation?
by 704278444
Sun Feb 23, 2014 10:05 pm
Forum: General Rate Laws
Topic: Rate law and products
Replies: 3
Views: 561

Re: Rate law and products

The rate law includes product when you are writing for a reverse reaction.
For example, for forward reaction: rate= k [reactants]
for reverse reaction: rate= k' [products]
by 704278444
Sun Feb 23, 2014 4:07 pm
Forum: General Rate Laws
Topic: Radical Chain Initation, 14.77
Replies: 3
Views: 605

Re: Radical Chain Initation, 14.77

are we responsible to know the material concerning radical chain initiation?
by 704278444
Sun Feb 23, 2014 4:02 pm
Forum: First Order Reactions
Topic: Quiz 2 practice
Replies: 6
Views: 1023

Re: Quiz 2 practice

got it! thank you!
by 704278444
Sun Feb 23, 2014 3:31 pm
Forum: First Order Reactions
Topic: Quiz 2 practice
Replies: 6
Views: 1023

Re: Quiz 2 practice

I have another related question. It wouldn't matter if this reaction is other order right? Half-life is always defined as the time required for half of the reactants to be consumed. So in any order, for this specific quiz problem, the amount of starting material always decreases by a factor of 8 aft...
by 704278444
Sat Feb 22, 2014 2:13 pm
Forum: General Rate Laws
Topic: Rate law with intermediates
Replies: 3
Views: 854

Re: Rate law with intermediates

I think you can.
by 704278444
Sat Feb 22, 2014 12:54 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: to determine the overall reaction
Replies: 6
Views: 1833

Re: to determine the overall reaction

ohh I got it. It is because H2O serves as a solvent here.
by 704278444
Sat Feb 22, 2014 12:47 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: to determine the overall reaction
Replies: 6
Views: 1833

Re: to determine the overall reaction

yay ok thank you! I have another question, when you are writing out the rate law do you not put H2O in it? for example, on 105 when you are using the rate law of the first step to substitute for intermediate, H2O is being omitted.
Thank you!
by 704278444
Sat Feb 22, 2014 11:57 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: to determine the overall reaction
Replies: 6
Views: 1833

to determine the overall reaction

To determine the overall reaction with multiple steps, do you cancel the molecules that appear on both reactant and product side and what are leftover are the overall reaction, regardless the relative speed of individual steps? For example, on question 14.105, we got the overall reaction by cancelin...
by 704278444
Sat Feb 22, 2014 12:17 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Self-Test 14.12A
Replies: 5
Views: 718

Re: Self-Test 14.12A

Me too!! That's why I was confused.
Can someone clarify further please? thank you.
by 704278444
Thu Feb 20, 2014 9:27 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Self-Test 14.12A
Replies: 5
Views: 718

Re: Self-Test 14.12A

I plugged ln k = Ae^(-Ea/RT) and solved for Ea directly.
Am I allowed to do that?
Thanks!
by 704278444
Thu Feb 20, 2014 6:13 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Self-Test 14.12A
Replies: 5
Views: 718

Self-Test 14.12A

I understand how to plug in data to the formulas to get the activation energy. When you plug in any sets of temperature and k, shouldn't the activation energy be the same all the time? (Just like the example 14.8) However, when I plugged in different sets of temperature and k, ie: 100 degree celcius...
by 704278444
Tue Feb 18, 2014 10:36 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Course Reader p.68
Replies: 1
Views: 378

Re: Course Reader p.68

The general formula for the formation of product is (1/b)d[P]/dt b in this case is 2 because it is forming two moles of NO2 in the balanced equation. Thus, 1/b= 1/2. This is where you get 1/2. Your question, (-1/a) is the consumption of reactant. That is why you have a negative sign in front. But we...
by 704278444
Mon Feb 17, 2014 9:59 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Law
Replies: 3
Views: 579

Re: Rate Law

We usually write the rate law in terms of consumption of reactants. But it really depends on the question. The question should specify.
by 704278444
Sat Feb 15, 2014 2:18 pm
Forum: First Order Reactions
Topic: Textbook Self-test 14.8A
Replies: 1
Views: 302

Textbook Self-test 14.8A

I understand how to get to the answer of this question.
I assumed that this reaction is first order and it is, since my calculation at the end is the same as the answer.
However, it is not specified in the question that it is first order. How are you suppose to know then?
by 704278444
Sat Feb 15, 2014 1:32 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Textbook example 14.4
Replies: 1
Views: 463

Re: Textbook example 14.4

Sorry nvm, I found out it says: "We need to plot the NATURAL LOGARITHM of the reactant concentration as a function of t."
by 704278444
Sat Feb 15, 2014 1:28 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Textbook example 14.4
Replies: 1
Views: 463

Textbook example 14.4

Why does it say that by plotting the data, if we get a straight line (or linear), then the reaction is first order? Isn't the first order reaction exponential? Shouldn't a linear slope be zero order?
Thanks!
by 704278444
Thu Feb 13, 2014 11:08 am
Forum: Administrative Questions and Class Announcements
Topic: Does Dr Lavelle teach 14C?
Replies: 3
Views: 664

Re: Does Dr Lavelle teach 14C?

does he teach 14c during other quarter tho?

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