Search found 59 matches

by 004263380
Sat Mar 15, 2014 11:10 am
Forum: *Alkanes
Topic: Neo vs tert
Replies: 1
Views: 369

Neo vs tert

Can neo- and tert- be used interchangeably? I know tert refers to when C is attached to 3 other carbons and neo has the formula C(CH3)3. It looks the same...
by 004263380
Wed Mar 12, 2014 4:29 pm
Forum: *Cycloalkenes
Topic: Priority
Replies: 4
Views: 880

Priority

What is the priority in naming/ numbering organic substances? Do we give the lowest numbers to bond first, then the functional groups, then the other substituents? What if there are double bonds, functional groups and other substituents (such as methyl and ethyl) in one molecule? Is different priori...
by 004263380
Wed Mar 12, 2014 4:06 pm
Forum: *Cycloalkenes
Topic: Naming cycloalkenes when functional groups are involved
Replies: 2
Views: 600

Naming cycloalkenes when functional groups are involved

When we number off the carbons for a cycloalkene or cycloalkyne do we give the lowest number to the functional group (for example if we see ether) before numbering the location of the double/triple bond?
by 004263380
Tue Mar 11, 2014 8:38 pm
Forum: *Alkanes
Topic: Naming
Replies: 2
Views: 489

Naming

What's the difference between using the systematic, common, and IUPAC name? Does common naming involve only ISO-, Neo-, sec-, and tert-?
by 004263380
Mon Mar 10, 2014 9:10 pm
Forum: *Cycloalkenes
Topic: Where to start counting Winter 2013 final 6A
Replies: 6
Views: 1650

Where to start counting Winter 2013 final 6A

Why Is the answer to 6A of final 2013 1,5,5,6 tetramethylcyclohex-1-ene and not 2,3,4,4 tetramethylcyclo-hex-ene? I thought that the double bond determines where 1 is and then we start counting based on what gives the 2nd substituent the smallest number.
by 004263380
Mon Mar 10, 2014 5:50 pm
Forum: *Organic Reaction Mechanisms in General
Topic: making larger rings
Replies: 1
Views: 563

making larger rings

Why is it easier to make and manipulate 5 and 6 membered rings than it is to make larger rings directly?
by 004263380
Mon Mar 10, 2014 4:17 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Winter 2012 final 1B
Replies: 1
Views: 507

Winter 2012 final 1B

How do we know that we are cooling NO and NO2 to 298 K and not cooling NO2 for the first step?
by 004263380
Mon Mar 10, 2014 3:31 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Lewis structures ch.4
Replies: 1
Views: 456

Lewis structures ch.4

When drawing Lewis structures (#7-10 of chapter 4) how do we know where to place the negative charge? For example: 7) why is the negative charge on S in SCN^-? 8) S2O3^-2 why is there a negative charge on each of the single bonded oxygens? 10) N3^- why is there a positive charge on one of the nitrog...
by 004263380
Mon Mar 10, 2014 3:24 pm
Forum: *Alkenes
Topic: Winter 2009 7B
Replies: 3
Views: 657

Winter 2009 7B

For 7B of the winter 2009 final, how do we know where on the molecule to place the DOUBLE bond?
by 004263380
Mon Mar 10, 2014 3:18 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Winter 2009 final 6A
Replies: 5
Views: 625

Winter 2009 final 6A

How do you know whether a reaction is more and less likely to occur at rm temp?
by 004263380
Mon Mar 10, 2014 3:16 pm
Forum: *Nucleophilic Substitution
Topic: Winter 2008 final 5C
Replies: 2
Views: 530

Winter 2008 final 5C

When drawing reaction mechanisms, how do we know whether to draw the molecules in 3D (as done in the solution) or 2D? Does it matter?
by 004263380
Mon Mar 10, 2014 3:13 pm
Forum: *Alkanes
Topic: -ylium
Replies: 2
Views: 529

-ylium

In what cases would we use the ending -ylium?
by 004263380
Mon Mar 10, 2014 3:10 pm
Forum: *Electrophilic Addition
Topic: Labeling structures in electrophilic additions
Replies: 4
Views: 664

Re: Labeling structures in electrophilic additions

How do we know whether we need to draw the 3D structures of molecules when drawing its reaction mechanism? And when to draw 2D when doing reaction mechanisms? Fall 2008 5C
by 004263380
Mon Mar 10, 2014 9:51 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2012 final 3a
Replies: 2
Views: 334

2012 final 3a

How do you know that chrome is the anode and copper is the cathode when the standard potentials are not given?
by 004263380
Mon Mar 10, 2014 9:05 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Newman projections
Replies: 4
Views: 784

Re: Newman projections

Are we allowed to use the model kit on the exam?
by 004263380
Sun Mar 09, 2014 2:58 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Residual entropy
Replies: 2
Views: 644

Residual entropy

Why does NO have a higher residual entropy than BF3?
by 004263380
Sun Mar 09, 2014 2:55 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Heat capacity
Replies: 2
Views: 544

Heat capacity

Why is the heat capacity higher for ethane than ethene?
by 004263380
Sat Mar 08, 2014 7:53 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Final 2008 3
Replies: 1
Views: 316

Final 2008 3

Why does the cell voltage INCREASE when Na2S solution is added to the Pb2+ and PbS forms
by 004263380
Sat Mar 08, 2014 6:32 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Newman projections
Replies: 4
Views: 784

Newman projections

In general, how can we draw Newman projections without using model kits? For example, how would we approach problems such as 8A of the 2007 final? Question 8A on the 2007 final states: "Draw a Newman projection for the most stable conformation of 2, 3-dimethyl-pentane looking down the C2---C3 a...
by 004263380
Sat Mar 08, 2014 5:34 pm
Forum: *Cycloalkanes
Topic: Question 6B on Winter 2007: axial vs equitorial
Replies: 2
Views: 448

Question 6B on Winter 2007: axial vs equitorial

Question 6B on the Winter 2007 Final Exam states: "Draw a structure which clearly shows the most stable conformation for 1-ethyl-1-isopropylcyclohexane." Why is ethyl placed in the axial direction and isopropyl equatorial direction? Why can't ethyl be placed in the equatorial direction and...
by 004263380
Thu Mar 06, 2014 5:09 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Equitorial vs. Axial
Replies: 2
Views: 650

Equitorial vs. Axial

What is the difference between equatorial and axial? How can we demonstrate these two characteristics in a diagram?
by 004263380
Thu Mar 06, 2014 4:58 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Drawing the hydrogens for different conformations
Replies: 2
Views: 630

Drawing the hydrogens for different conformations

Does it matter where we place the hydrogens on each carbon atom of different conformations? In other words, do we have to place each hydrogen atom exactly as the book does for each conformation? (same angle and orientation)
by 004263380
Thu Mar 06, 2014 4:00 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Newman Projections
Replies: 2
Views: 535

Newman Projections

When we draw the newman projection for molecules such as 1-bromo-2-cholorethane, how do we know the placement of each atom on the tetrahedral?? for example for 3.6, when drawing the newman projection how do we know that the bromine atom will be on top with the two hydrogen atoms pointing downwards? ...
by 004263380
Tue Mar 04, 2014 4:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm correction
Replies: 1
Views: 811

Midterm correction

Who do we go to if we think we found a grading mistake on the midterm?
by 004263380
Mon Mar 03, 2014 7:08 pm
Forum: *Alkanes
Topic: 1.9c
Replies: 1
Views: 310

1.9c

why is 1. 9C isopentane when the longest chain has only 4 carbons?
by 004263380
Mon Mar 03, 2014 7:06 pm
Forum: *Alkanes
Topic: using the lowest number when naming
Replies: 3
Views: 486

using the lowest number when naming

How do we determine what the lowest combination of numbers we need to use when naming? For example: for 1.21: why is it 5-methylcyclopenta-1,3-diene and not 3-methylcyclopenta-1,4-diene? clearly 3 is less than 4. My question is in regards of naming all kinds of compounds, not just the cyclo-. Is the...
by 004263380
Wed Feb 26, 2014 10:20 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Unique reaction rate vs reaction rate
Replies: 3
Views: 764

Unique reaction rate vs reaction rate

What is the difference between the unique reaction rate of a reaction and a reaction rate? I thought that you divide by the stoichiometric coefficient only when we are asked for the UNIQUE reaction rate. How come for number 1 of quiz two, they divided by the coefficient even though it didn't ask for...
by 004263380
Sun Feb 23, 2014 12:39 pm
Forum: First Order Reactions
Topic: Quiz 2 practice
Replies: 6
Views: 950

Quiz 2 practice

Why will the amount of starting material decrease by a factor of 8 after 3 half-lives in a first order reaction? What equation am I looking at and how can I relate it to this problem?
by 004263380
Sun Feb 23, 2014 10:29 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetically stable vs. Thermodynamically stable.
Replies: 3
Views: 51462

Kinetically stable vs. Thermodynamically stable.

I understand that kinetics deals with the rate of a reaction and thermodynamics deals with whether the rxn is forward or backwards. However, what does it mean to be kinetically stable/unstable and thermodynamically stable/unstable?
by 004263380
Tue Feb 18, 2014 11:55 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Slow step
Replies: 4
Views: 3280

Slow step

How do you determine which is the slop step in a multistep reaction? 14.91
by 004263380
Tue Feb 18, 2014 11:53 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetic Data
Replies: 1
Views: 410

Kinetic Data

What is kinetic data? How do we determine the conditions under which to use kinetic data? (14.89)
by 004263380
Tue Feb 18, 2014 11:15 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: radical chain initiating
Replies: 2
Views: 609

radical chain initiating

How do you know that a reaction might be radical chain initiating? (14.77) What exactly does it mean to be radical chain initiating
by 004263380
Tue Feb 11, 2014 9:22 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: winter 2010 5
Replies: 2
Views: 356

Re: winter 2010 5

Yes, delta H sub c does stand or enthalpy of combustion
by 004263380
Tue Feb 11, 2014 9:08 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: at equilibrium
Replies: 2
Views: 426

Re: at equilibrium

delta G
by 004263380
Tue Feb 11, 2014 9:57 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: delta s with changing temperature
Replies: 2
Views: 545

Re: delta s with changing temperature

1) what if I'm dealing with delta S= (CdeltaT)/T and delta S = Cln (T2/T1)? (notice both equations don't have n). Which equation do I use then to calculate entropy when temperature is changing? 2) Again: For question 4 of midterm 2007, the second equation was used, however, for the past chem quiz (w...
by 004263380
Mon Feb 10, 2014 9:14 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: delta s with changing temperature
Replies: 2
Views: 545

delta s with changing temperature

when can we use delta S=(nCdeltaT)/ T and delta S=Cln (T2/T1)? For question 4 of midterm 2007, the second equation was used, however, for the past chem quiz (which had the same question just different numbers) the first equation was used. I tried using the first equation for 4 of midterm 2007 but go...
by 004263380
Sun Feb 09, 2014 2:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium Constant hw 10.85
Replies: 2
Views: 576

Equilibrium Constant hw 10.85

why would raising the temperature favor the formation of reactants when the equilibrium constant is smaller in comparison to another equilibrium constant? isn't K = products over reactants? if K is smaller then there would be more reactants. Therefore, shouldn't there be an increase in products?
by 004263380
Sat Feb 08, 2014 4:55 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: delta U and delta H
Replies: 1
Views: 71086

delta U and delta H

Is delta U = to delta H only when the number of moles of gases do not change, the volume does not change, and pressure is constant?
If the number of moles do change, but the volume is still constant we need to use: delta U = delta H - delta n R T right?
by 004263380
Sat Feb 08, 2014 3:40 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Internal energy
Replies: 2
Views: 465

Re: Internal energy

Is the internal energy zero for an irreversible path too? When exactly is delta U zero?
by 004263380
Sat Feb 08, 2014 3:32 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Internal energy
Replies: 2
Views: 465

Internal energy

Is the internal energy of an ideal gas expanding reversibly zero?
by 004263380
Sat Feb 08, 2014 2:01 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Standard states
Replies: 1
Views: 335

Standard states

How do we recognize when a substance is in its standard state? (aka in its purest form?) Is there a particular chemical equation?
by 004263380
Sat Feb 08, 2014 12:17 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Q vs. K
Replies: 1
Views: 376

Q vs. K

What is the difference between Q and K. How come sometimes we solve G using Q and other times K?
by 004263380
Sat Feb 08, 2014 12:03 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltsmann eq
Replies: 1
Views: 554

Boltsmann eq

How do you determine the microstates a molecule has without having to draw all the different configurations of it? why is W (degeneracy) = 2^N? why is there a 2??? is there more than one way to figure out W?
by 004263380
Thu Feb 06, 2014 11:52 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: spontaneous Reduction
Replies: 1
Views: 288

spontaneous Reduction

Why does reduction take place at the electrode with higher concentration? (13.99)
by 004263380
Thu Feb 06, 2014 3:34 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Equilibrium Constant
Replies: 1
Views: 371

Equilibrium Constant

How do you know whether the products or the reactants will be favored in terms of E (knot), G(knot), and any other way we can determine which side is favored? When we say the product is favored does it mean the reaction prefers a forward reaction to produce more products or that there are more produ...
by 004263380
Wed Feb 05, 2014 9:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Winter 2010 Midterm #4
Replies: 3
Views: 507

Re: Winter 2010 Midterm #4

Why can't we assume the reaction is under constant pressure? The question states that the volume is changing...
by 004263380
Wed Feb 05, 2014 9:03 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: internal energy
Replies: 3
Views: 676

Re: internal energy

Midterm 2012 number 5. A system undergoes a two step process. In step one it absorbs 50 J of heat at constant volume. so internal energy is 50J. in step 2 it releases 5 J of heat at 1 atm and it is returned to its ORIGINAL internal energy. The internal energy for step 2 is -50J. Why is it negative?
by 004263380
Wed Feb 05, 2014 4:34 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E (knot) versus E
Replies: 1
Views: 3194

E (knot) versus E

What is the difference between E(knot) and E? Is E zero in a concentration cell or E(knot)?
by 004263380
Wed Feb 05, 2014 3:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: internal energy
Replies: 3
Views: 676

internal energy

Why does the internal energy change signs when the process returns to its original internal energy?
by 004263380
Wed Feb 05, 2014 2:51 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: K value
Replies: 1
Views: 306

K value

What equation can we use to calculate the K value given only the Eknot value and n? (Midterm 2011 7&8 C)
by 004263380
Wed Feb 05, 2014 2:47 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Winter 2010 Midterm #4
Replies: 3
Views: 507

Winter 2010 Midterm #4

Do we use C=3/2R only when there is constant volume? If so, why is that 3/2R was used to calculate entropy when the volume of nitrogen gas at 3 L is compressed suddenly (and irreversibly) to .500 L by driving in a piston? This is occurring in an internal combustion engine and the temperature of the ...
by 004263380
Wed Feb 05, 2014 2:42 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Midterm 2009 # 8
Replies: 3
Views: 519

Midterm 2009 # 8

How do we know that when finding the Q value for a concentration cell (using the Nernst eq) we need to divide the concentration of the anode by the concentration of the cathode? How did they come up with that ratio? the cell is Ag(s)l Ag+(aq)llAg+(aq)l Ag(s).
by 004263380
Wed Feb 05, 2014 2:37 pm
Forum: Balancing Redox Reactions
Topic: Oxidation number
Replies: 1
Views: 365

Oxidation number

How do you determine the oxidation number for Mn and NO on the product side for the following?
1) MnO4^- +8H^+ + 5e---> Mn^2+ +4H2O
2) NO3^- + 4H^+ 3e ---> NO + 2H2O
by 004263380
Wed Feb 05, 2014 2:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Voltaic cells
Replies: 1
Views: 287

Voltaic cells

What is happening in a voltaic cell? Why would the cell potential increase with the addition of ions? Why would a forward reaction increase cell potential? (winter 2007 midterm question 5B)
by 004263380
Wed Feb 05, 2014 2:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Winter 2007 Midterm Problem 8
Replies: 4
Views: 631

Winter 2007 Midterm Problem 8

Question in midterm: In a neuron the concentration of K+ ions inside the cell is about 20-30 times greater than the outside. What potential difference between the inside and the outside of the cell would you expect to measure if the difference is due only to the imbalance of potassium ions? My quest...
by 004263380
Tue Feb 04, 2014 7:37 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Standard cell potential (E knot)
Replies: 1
Views: 641

Standard cell potential (E knot)

Why is the standard cell potential 0 in a concentration cell? And what is happening in a concentration cell?
by 004263380
Tue Feb 04, 2014 7:26 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Internal Energy
Replies: 1
Views: 320

Internal Energy

What is the concept behind internal energy? What exactly are we solving for and how does it affect the system when there are changes in volume, temperature, and pressure?
by 004263380
Tue Feb 04, 2014 7:20 pm
Forum: Balancing Redox Reactions
Topic: inert metal
Replies: 2
Views: 559

inert metal

When do we add an inert metal (ex: Pt) to a cell diagram? Why do we add it?
by 004263380
Thu Nov 14, 2013 9:08 am
Forum: Naming
Topic: Naming Coordination Compounds
Replies: 1
Views: 446

Naming Coordination Compounds

My TA said that professor Lavelle posted a chart on how to name coordination compounds. Where can we find that chart?

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