Search found 60 matches
- Thu Mar 10, 2016 11:18 pm
- Forum: *Ethers
- Topic: final exam question
- Replies: 1
- Views: 638
final exam question
Do we need to know any functional groups besides ketone, ether, carboxylic acid, alcohol, and aldehyde for the final?
- Wed Mar 09, 2016 3:13 pm
- Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
- Topic: trans/cis with 3 substituents
- Replies: 1
- Views: 468
trans/cis with 3 substituents
if told to draw a cyclohexane that is either trans or cis with 3 substituents, how do you know which do to make up and which to make down for trans? would you make them all either up or down for cis?
- Wed Mar 09, 2016 2:35 pm
- Forum: *Alcohols
- Topic: priority for naming
- Replies: 1
- Views: 719
priority for naming
Is it true that ethers and alcohols are functional groups that dont get priority in naming?
- Tue Mar 08, 2016 2:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: final exam question
- Replies: 12
- Views: 5809
final exam question
Hello, I noticed in the practice finals there are a few questions that ask you to derive rate laws using integrals such as 4A on the 2014 final which asks to derive the integrated rate law for a second order reaction with A as the only reactant. However, I thought that I remembered Professor Lavelle...
- Wed Mar 02, 2016 8:56 pm
- Forum: *Electrophilic Addition
- Topic: PLEASE HELP intermediates
- Replies: 1
- Views: 602
PLEASE HELP intermediates
Is there always only 1 intermediate in electrophilic addition when there are 2 transition states? I thought that there were 2 in the example of Br2 attaching to a large molecule with a double bond since one would be the Br attached to the large molecule with a carbo cation and one would be the secon...
- Wed Mar 02, 2016 2:30 pm
- Forum: *Free Energy of Activation vs Activation Energy
- Topic: arrhenius vs temp
- Replies: 1
- Views: 564
arrhenius vs temp
what exactly is the relationship between arrhenius and temp
- Wed Mar 02, 2016 2:29 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: quiz 3
- Replies: 1
- Views: 594
quiz 3
will we have to know anything about kinetic control for quiz 3?
- Wed Mar 02, 2016 2:21 pm
- Forum: *Alkanes
- Topic: prioritizing naming
- Replies: 2
- Views: 463
prioritizing naming
If there are 2 substituents that are the same length apart, which would get prioritized for the lower number in naming: chloro or ethyl? or chloro or methyl?
- Wed Mar 02, 2016 12:23 am
- Forum: *Electrophiles
- Topic: AlCl3 Friedal Crafts Alkylation
- Replies: 3
- Views: 1977
Re: AlCl3 Friedal Crafts Alkylation
but why wouldnt it attack it from the lone pairs and not the single bond on the RCL
- Wed Mar 02, 2016 12:18 am
- Forum: *Alkanes
- Topic: quiz 3 prep 1 number 4
- Replies: 4
- Views: 899
Re: quiz 3 prep 1 number 4
could you have drawn this in a straight line instead of curved the way it is in the answers?
- Mon Feb 29, 2016 7:43 pm
- Forum: *Alkanes
- Topic: quiz 3 prep 1 number 2
- Replies: 2
- Views: 670
quiz 3 prep 1 number 2
This question asks to name ch3chch3chch2ch3c(ch3)3 and I got 3 ethyl 2,2,4 trimethylpentane however the answer is 2,2,4 trimethyl ethylpentane and I dont understand why the triMethyl is getting alphabatized and placed before the Ethyl
- Mon Feb 29, 2016 7:38 pm
- Forum: *Alkanes
- Topic: quiz 3 prep 1 number 4
- Replies: 4
- Views: 899
quiz 3 prep 1 number 4
For this question it asks to draw 7-flouro-3-methyl-4-vinyl-nonane, However in the answer the longest chain only has 8 carbons even though its nonane (9 carbons) and there is a double bond even though it is -ane not -ene so I'm confused why this is. Also, I thought vinyl meant c2h3R and I do not see...
- Sat Feb 27, 2016 4:31 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: 4.30
- Replies: 3
- Views: 771
4.30
This question asks if the activation energy in an organic rxn is 125 kj/mol, will the rxn occur at room temperature and I was wondering why the answer is no
- Sat Feb 27, 2016 4:08 pm
- Forum: *Complex Reaction Coordinate Diagrams
- Topic: 4.25
- Replies: 1
- Views: 1376
4.25
In 4.25 it shows an arrow flowing from a double bond to a Br2 molecule. In the br2 molecule the br that the arrow first points to is marked as electropositive in the answers and the second br is marked as electronegative and I was wondering how to decipher which would be the negative and which would...
- Sat Feb 27, 2016 3:30 pm
- Forum: *Electrophiles
- Topic: nucleophiles vs electrophiles
- Replies: 2
- Views: 704
nucleophiles vs electrophiles
Do we need to memorize the nucleophiles and electrophiles listed in the o chem book
- Sat Feb 27, 2016 3:08 pm
- Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
- Topic: alphabetical order
- Replies: 1
- Views: 501
alphabetical order
is it only the tert- and sec- group that you do not look at the prefix when placing in alphabetical order?
- Wed Feb 24, 2016 5:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Quiz 3 Winter 2016
- Replies: 48
- Views: 20487
Re: Quiz 3 Winter 2016
I was wondering if anything from the end of ch 15 will be on the quiz
- Tue Feb 16, 2016 6:06 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: activation energy
- Replies: 3
- Views: 756
Re: activation energy
in using the arrhenius how would you know what to plug in for A?
- Mon Feb 15, 2016 4:18 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: activation energy
- Replies: 3
- Views: 756
activation energy
How can you find the activation energy from just knowing the order of the reaction and k?
- Sun Feb 14, 2016 4:52 pm
- Forum: First Order Reactions
- Topic: practice quiz 1 number 9
- Replies: 1
- Views: 509
practice quiz 1 number 9
This question asks how long it takes the reactant concentration to drop from .0840 to .0220 with k= 8.39. I used ln final/initial = -kt and got .159 seconds but the answer is 4 seconds, and I was wondering what the right way to do this was?
- Tue Feb 09, 2016 7:07 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760366
Re: Chemistry Jokes
I hope everyone is feeling solid (with low entropy) for the midterm tomorrow!
- Wed Feb 03, 2016 5:42 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 11.19 and 11.83
- Replies: 3
- Views: 718
11.19 and 11.83
Hello, both 11.19 and 11.83 ask to calculate the equilibrium constant k for chemical equations, however 19 just simply asks to calculat k at 25 degrees celsius and 83 asks to calculate k at 25 and at 150 degrees celsius. However, in 83 to solve this problem it uses delta G= delta h - T delta S, and ...
- Mon Feb 01, 2016 5:11 pm
- Forum: Balancing Redox Reactions
- Topic: midterm
- Replies: 1
- Views: 458
midterm
Hello,
Sorry I'm not sure where to properly ask this question, but I was wondering what all the sections the midterm will be covering are?
Sorry I'm not sure where to properly ask this question, but I was wondering what all the sections the midterm will be covering are?
- Mon Jan 25, 2016 9:15 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Homework 9.45
- Replies: 2
- Views: 1610
Re: Homework 9.45
for this problem, I was also wondering why they divide the enthalpy of fusion for ethanol by the freezing point and not the melting point to find its melting entropy
- Mon Jan 25, 2016 8:59 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 9.43
- Replies: 1
- Views: 511
9.43
for this question it says that 50g h20 at 20 degrees celsius is mixed with 65g of h20 at 50 degrees celsius and wants delta s and delta s total. In the solutions manual it uses q=-q and uses 75.3 for the specific heat. I was wondering where the number 75.3 comes from
- Mon Jan 25, 2016 7:46 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: delta h, q, and delta u
- Replies: 1
- Views: 1376
delta h, q, and delta u
does q= delta h at constant pressure? and does delta u = delta h at constant volume?
- Mon Jan 25, 2016 7:44 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: delta g = 0
- Replies: 1
- Views: 775
delta g = 0
does delta g equal zero when the temperature is 0 or when its at boiling point?
- Sat Jan 23, 2016 11:24 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: q=nc delta t
- Replies: 1
- Views: 1604
q=nc delta t
In the homework for chapter 8 I noted that sometimes in calculating q the book sometimes multiplied the specific heat and the change in temperature by the grams and and other times multiplied the specific heat and change in temp by mols and I was wondering why that is
- Wed Jan 20, 2016 9:19 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 9.71
- Replies: 1
- Views: 595
9.71
In question 9.71 it asks Which substance would you expect to have the highest molar entropy in the liquid phase, benzene, methanol (CH3OH), or 1-propanol (CH3CH2CH2OH)? In the solutions manual it says that it is benzene because it has more of a rigid shape. I was wondering what it meant by rigid sha...
- Wed Jan 20, 2016 9:16 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: 9.89
- Replies: 1
- Views: 403
9.89
In question 9.89 it asks, Some entries for S in Appendix 2A are negative. What is common about these entries, and why would the entropy be negative? The solutions manuals answer did not really make sense to me and I was wondering if someone can explain the reasoning behind this. Is it just because t...
- Wed Jan 20, 2016 9:14 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 9.103
- Replies: 2
- Views: 577
9.103
In question 9.103 it asks A scientist proposed the following two reactions to produce ethanol, a liquid fuel: C2H4 (g) + H20 (g) -> CH3CH2OH (l) C2H6 (g) + H20 (g) -> CH3CH2OH (l) + H2 (g) Assume standard-state conditions and determine if either reaction is thermodynamically spontaneous. I initially...
- Mon Jan 18, 2016 3:03 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: molar heat capacity
- Replies: 2
- Views: 700
molar heat capacity
What would cause one molecular substance to have a higher molar heat capacity than another molecular substance?
- Mon Jan 11, 2016 5:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 8.117
- Replies: 1
- Views: 393
8.117
In question 8.117 it states One step in the production of hydrogen as a fuel is the reaction of methane with water vapor: CH4 + H2O --> CO2 + 3 H2 enthalpy= -318 kJ What is the change in internal energy for the production of 1.00 mol H2? In the solutions manual they multiply by 2/3 mol to find the...
- Mon Jan 04, 2016 5:51 pm
- Forum: Phase Changes & Related Calculations
- Topic: adiabatic processes
- Replies: 1
- Views: 787
adiabatic processes
Regarding question 8.15 which asks, in an adiabatic process, indicate whether which statements are true, false, or uncertain in a closed system a) internal energy equals 0 b) heat equals 0 c) heat is less than 0 d) internal energy equals heat e) internal energy equals work I was wondering if someone...
- Wed Dec 02, 2015 2:18 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: when given all initial values
- Replies: 1
- Views: 382
when given all initial values
When you are given all of the initial concentrations for an equation, is it safe to always just calculate the Q and compare it to the K to determine which way the reaction is going? I remember Professor Lavelle saying in office hours that this strategy does not always work and that sometimes we shou...
- Wed Dec 02, 2015 2:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: steric number
- Replies: 2
- Views: 2788
steric number
A tutor taught me how to calculate the steric number to easily determine the geometry of a structure based on its chemical formula, but I forgot how to calculate this number. Does anyone know how to get the steric number? I only remember that oxygens are not counted or included in this number.
- Wed Nov 25, 2015 10:46 am
- Forum: Conjugate Acids & Bases
- Topic: formulas for conjugate bases
- Replies: 1
- Views: 692
formulas for conjugate bases
How do you write the formula for a conjugate base? For example, CH3COOH?
- Mon Nov 16, 2015 12:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: sig figs
- Replies: 1
- Views: 469
sig figs
while doing the homework I noticed that sometimes my answers sig figs didnt match up with the books answers. For this section, is it a good idea to keep the amount of sig figs matched to the amount of sig figs that will be in the final answer? Or should we keep a lot of sig figs and only cut down at...
- Sun Nov 15, 2015 5:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: setting x= very close to 0
- Replies: 1
- Views: 422
setting x= very close to 0
So can you only set x to a very small number close to 0 when its something - x or can you also do this when it is something + x
- Sun Nov 15, 2015 3:46 pm
- Forum: Naming
- Topic: pentaaquachloroiron(III)
- Replies: 1
- Views: 1663
pentaaquachloroiron(III)
For pentaaquachloroiron(III) would the chemical formula be:
[Fe(H2O)5 (Cl) ] 2+ since theres no counter atom
or
[Fe (H2O)5 Cl)3] to make a neutral charge ?
[Fe(H2O)5 (Cl) ] 2+ since theres no counter atom
or
[Fe (H2O)5 Cl)3] to make a neutral charge ?
- Sat Nov 14, 2015 4:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: atm
- Replies: 2
- Views: 577
atm
Do you usually want pressure to be in the units of atm?
- Sat Nov 14, 2015 3:26 pm
- Forum: Naming
- Topic: complex ion
- Replies: 2
- Views: 636
complex ion
On page 49 of the green workbook number 9 it says:
name the complex ion
[Cu(NH3)CL5] 3-
and the answer is either amminepentachlorocuprate (II) ion or amminepentachlorocopper(II) ion
why are there 2 possible answers? Is it because there is no counter ion?
name the complex ion
[Cu(NH3)CL5] 3-
and the answer is either amminepentachlorocuprate (II) ion or amminepentachlorocopper(II) ion
why are there 2 possible answers? Is it because there is no counter ion?
- Sat Nov 14, 2015 2:12 pm
- Forum: Naming
- Topic: using the word ion
- Replies: 1
- Views: 420
using the word ion
Should we just make it a general rule to attach the word "ion" to the end of every name?
carbonato
When there are 2 carbonatos, do we use bis- or di- ?
oxalato
when writing our the formula for oxalato, can we abbreviate it ox or do we need to write c2o4?
- Wed Nov 11, 2015 9:21 pm
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 3
- Views: 653
Re: Naming Coordination Compounds
For this first one, I thought it would be chromium III not chromate III since it is a cation. Do you also add -ate to cations?
- Wed Nov 11, 2015 9:15 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: (edta) Ligand's Binding Sites
- Replies: 1
- Views: 722
Re: (edta) Ligand's Binding Sites
oxygens want 2 lone pairs and 2 bonds, so when the oxygens with 3 lone pairs make a bond, it is the most favorable. This happens 4 times in edta. The two nitrogen are also left with one single lone pair which can become a bond as well. Altogether, this creates 6 sites for bonds making edta hexadenta...
- Tue Nov 10, 2015 1:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pg 53 green workbook #10, converting to atm
- Replies: 1
- Views: 504
pg 53 green workbook #10, converting to atm
"For the following rxn, if initially .1 mol h2o is placed in a 4 l vessel, what are the equilibrium partial pressures of each product and reactant? kp= 3.72 at 1000 k h2o + c = h2 + co " For this problem I got x=.034 and plugged that number in to calculate the equilibrium of all of the rea...
- Tue Nov 03, 2015 3:48 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: square pyramidal bond angle
- Replies: 2
- Views: 2392
square pyramidal bond angle
IS the bond angle for square pyramidal 90 degrees or less than 90 degrees?
- Mon Nov 02, 2015 2:29 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Quiz 1 uncertainty question
- Replies: 1
- Views: 754
Quiz 1 uncertainty question
"An electron is moving at v=3.78x10^5 m/s. A neutron is moving at the same velocity. Which particle is the position known with the greatest precision and why"
For this question would it be the electron since it has a smaller mass? Or would it be a neutron because that has a greater mass?
For this question would it be the electron since it has a smaller mass? Or would it be a neutron because that has a greater mass?
- Wed Oct 28, 2015 8:01 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: bond order
- Replies: 1
- Views: 537
bond order
Is a molecule more stable with a larger bond order? I thought that bond order correlated with the type of bond (single, double, triple) and that the more bonds there were the shorter the bond was, and the less stable it was. But do short bonds mean that the bond is more stable? In the practice quiz ...
- Tue Oct 27, 2015 4:21 pm
- Forum: Hybridization
- Topic: Coefficients for Hybridization
- Replies: 1
- Views: 508
Re: Coefficients for Hybridization
it would just be sp^3. You only want to look at how many regions of electron density there are with hybridization, not at where the elements are in the periodic table. Since there are 4 regions of electron density, the hybridization is sp^3
- Sun Oct 25, 2015 5:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: ground state electron configurations
- Replies: 3
- Views: 4299
Re: ground state electron configurations
I'm getting my answers from the solutions manual, and they had that answer which is why I am confused. Are you suggesting that the solutions manual is wrong?
- Sat Oct 24, 2015 4:53 pm
- Forum: Ionic & Covalent Bonds
- Topic: ground state electron configurations
- Replies: 3
- Views: 4299
ground state electron configurations
For 3.19, it asks the electron configuration for sb (3+). I put [kr] 4d10 5p2 because I thought that you take off the s orbital first, but the answer is [kr] 4d10 5s. However, in a similar problem 3.5, they say that the electron configuration for bi(3+) is [xe] 5d10 6p2 since they took off the s orb...
- Tue Oct 20, 2015 10:14 am
- Forum: Dipole Moments
- Topic: VSEPR theory
- Replies: 1
- Views: 636
VSEPR theory
I was wondering if someone could explain to me how to tell the difference between when a molecule will be AX3, AX4,AX3E,AX2E,AX2,and AX2E2. For example, how do you know that CH2 would be AX2E, but CH2(2+) would just be AX2?
- Thu Oct 15, 2015 12:12 pm
- Forum: Lewis Structures
- Topic: Drawing a Lewis Structure with a double/triple bond
- Replies: 4
- Views: 1324
Drawing a Lewis Structure with a double/triple bond
When drawing a lewis structure with a double/triple bond, how does one know to give that structure a double bond instead of just a single bond with more "." around it? For example, with H2CO, how do you know to draw it with a double bond between the C and O and 4 "." around the O...
- Thu Oct 15, 2015 12:03 pm
- Forum: Resonance Structures
- Topic: Most Important Resonance Structures
- Replies: 3
- Views: 858
Re: Most Important Resonance Structures
How would you know which N to give a +1, 0, or -1 charge to?
- Tue Oct 06, 2015 12:43 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Not understanding the use of ml
- Replies: 2
- Views: 668
Not understanding the use of ml
I do not fully understand the quantum value of ml. Does it determine if an element is magnetic or does it determine the orbital? Also, say that n=4, l=2, and ml=-2. How would I use that information to determine how many electrons can have those quantum numbers in an atom?
- Thu Oct 01, 2015 11:29 am
- Forum: Significant Figures
- Topic: Exact numbers in the final answers
- Replies: 4
- Views: 1141
Exact numbers in the final answers
Hey guys, While I did the homework over the summer I noticed that a lot of times I would come up with an answer of say 40.07, and the answer in the solutions manual would say something like 40.13. This probably has to do with discrepancies in the amount of sig figs used throughout all of the calcula...
- Wed Sep 30, 2015 4:44 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: atomic emission vs atomic absorbtion
- Replies: 4
- Views: 1114
atomic emission vs atomic absorbtion
After watching the videos I am very confused about the difference between atomic emission spectrum and atomic absorption spectrum. My interpretation from the videos was that these 2 ideas were the same concept, although now it has become clear that they have differences between them. I was wondering...