Search found 53 matches
- Thu Mar 15, 2018 10:18 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Negative Ea
- Replies: 3
- Views: 598
Negative Ea
Can activation energy be negative?
- Thu Mar 15, 2018 8:19 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Final Pseudo Equilibrium
- Replies: 1
- Views: 345
Final Pseudo Equilibrium
Will we need to know pseudo equilibrium for the final?
- Thu Mar 15, 2018 8:14 pm
- Forum: General Rate Laws
- Topic: Unique Rate [ENDORSED]
- Replies: 5
- Views: 1030
Re: Unique Rate [ENDORSED]
thanks!
- Sat Mar 03, 2018 1:50 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: figuring out n and m
- Replies: 3
- Views: 546
Re: figuring out n and m
as of what we have learned, we must be given the necessary information to find out n and m.
- Sat Mar 03, 2018 1:45 pm
- Forum: General Rate Laws
- Topic: 15. 17 [ENDORSED]
- Replies: 2
- Views: 431
Re: 15. 17 [ENDORSED]
the values in experiment 1 and 4 the initial rate stays the same and the concentrations of A and B stay the same. C however changes between the 1 and 4 experiment so it doesn't contribute to the initial rate.
- Sat Mar 03, 2018 12:13 pm
- Forum: General Rate Laws
- Topic: Unique Rate [ENDORSED]
- Replies: 5
- Views: 1030
Unique Rate [ENDORSED]
Can someone clarify what unique rate laws are? I did not understand what Lavelle said during class about this. Thanks!
- Sat Mar 03, 2018 12:11 pm
- Forum: General Rate Laws
- Topic: Overall order [ENDORSED]
- Replies: 6
- Views: 1012
Re: Overall order [ENDORSED]
Question #15 in the hw can help with understanding this. reactants [CH3Br] and [OH-] both end in having the order = 1 (n=1, m=1) so if you add n and m you get 2. the OVERALL reaction order is 2 while the individual reactions have the reaction order of 1.
- Sat Mar 03, 2018 12:09 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Reaction Order [ENDORSED]
- Replies: 2
- Views: 454
Re: Reaction Order [ENDORSED]
you can use the hw question #15 to help your understanding on this. [CH3Br] and [OH-] both end in having the order = 1 (n=1, m=1) so if you add n and m you get 2. the OVERALL reaction order is 2 while the individual reactions have the reaction order of 1.
- Sat Mar 03, 2018 12:04 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: 15.15 [ENDORSED]
- Replies: 5
- Views: 753
Re: 15.15 [ENDORSED]
the order for both [CH3Br] and [OH-] are n=1 so the overall reaction order would be 2 because 1+1= 2
- Sat Mar 03, 2018 12:02 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Quiz 3
- Replies: 6
- Views: 854
Re: Quiz 3
I read on another question that the test would cover up to question #49 I believe... Can anyone clear this up?
- Sat Mar 03, 2018 11:57 am
- Forum: Second Order Reactions
- Topic: 15.17
- Replies: 4
- Views: 684
Re: 15.17
you use experiments 1 and 4 to find [C] in respect to [A] and [B] because A and B values are the same values. This helps in finding the order of [C] because the values for [C] in experiment 1 and 4 are different.
- Sat Mar 03, 2018 11:46 am
- Forum: General Rate Laws
- Topic: Differential vs Integrated [ENDORSED]
- Replies: 2
- Views: 374
Differential vs Integrated [ENDORSED]
How do you determine when to use the differential rate law vs the integrated rate law? Does the question and what is given help?
- Sat Mar 03, 2018 11:44 am
- Forum: Zero Order Reactions
- Topic: Difference between zero, first, second [ENDORSED]
- Replies: 3
- Views: 2438
Re: Difference between zero, first, second [ENDORSED]
First Order
slope = -k
n=1
-d[A]/dt = k[A]^1
ln[A] = -kt
Second Order
slope = k
n=2
-d[A]/dt = k[A]^2
1/[A] = kt + (1/[A])0
Zero Order
Slope = -k
n=0
-d[A]/dt = k
[A] = -kt
slope = -k
n=1
-d[A]/dt = k[A]^1
ln[A] = -kt
Second Order
slope = k
n=2
-d[A]/dt = k[A]^2
1/[A] = kt + (1/[A])0
Zero Order
Slope = -k
n=0
-d[A]/dt = k
[A] = -kt
- Sat Mar 03, 2018 11:41 am
- Forum: General Rate Laws
- Topic: Calculating Rate vs. Unique Average Rate
- Replies: 2
- Views: 328
Re: Calculating Rate vs. Unique Average Rate
within the problem they should state whether or not it is average or not.
- Tue Feb 20, 2018 6:10 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation state
- Replies: 7
- Views: 975
Re: Oxidation state
why is O3's oxidation state 0?
- Tue Feb 20, 2018 1:52 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation state
- Replies: 7
- Views: 975
Oxidation state
what is an easy way to figure out the oxidation states?
- Sun Feb 11, 2018 9:00 pm
- Forum: Phase Changes & Related Calculations
- Topic: calculating a phase change in a reaction
- Replies: 5
- Views: 785
Re: calculating a phase change in a reaction
I'm also confused on differentiating this problem
- Sun Feb 11, 2018 8:58 pm
- Forum: Phase Changes & Related Calculations
- Topic: 8.19
- Replies: 3
- Views: 551
Re: 8.19
.38J/g C is the specific heat of Copper, these values can be found in a table in chapter 8
- Sat Feb 03, 2018 8:43 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta G [ENDORSED]
- Replies: 4
- Views: 504
Re: Delta G [ENDORSED]
Delta G is not always negative. When it is negative it implies that it is spontaneous. When it is positive it implies it is nonspontaneous
- Sat Feb 03, 2018 8:41 pm
- Forum: Calculating Work of Expansion
- Topic: Calculating Work of Expansion
- Replies: 4
- Views: 678
Re: Calculating Work of Expansion
Some TA's have said it might be good to know how certain equations are derived because in previous tests he has asked to show how to get a formula.
- Sat Feb 03, 2018 8:38 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Which value of R to use?
- Replies: 3
- Views: 395
Re: Which value of R to use?
The method you have been using should work because the units and conversions should be equal.
- Sat Feb 03, 2018 8:34 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Degeneracy vs Disorder
- Replies: 4
- Views: 573
Re: Degeneracy vs Disorder
Im confused on this as well
- Tue Jan 23, 2018 5:03 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 5
- Views: 896
Re: Hess's Law
they can be crossed out if they are of equal amounts
- Tue Jan 23, 2018 4:56 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam
- Replies: 7
- Views: 1229
Steam
In class Lavelle asked why does steam cause severe burns. Can someone explain this process in depth please.
- Tue Jan 23, 2018 4:48 pm
- Forum: Phase Changes & Related Calculations
- Topic: HW 8.31
- Replies: 3
- Views: 489
Re: HW 8.31
will there be a question similar to this on the test?
- Tue Jan 23, 2018 4:46 pm
- Forum: Phase Changes & Related Calculations
- Topic: Practice Test?
- Replies: 2
- Views: 325
Re: Practice Test?
there are no practice tests but some UA's have made worksheets you could practice from. One of them is from Karen Leung I believe. She posted it here so if you search her name it'll probably pop up.
- Sun Jan 21, 2018 11:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 3 Test Topic is endorsed
- Replies: 37
- Views: 4879
Re: Week 3 Test Topic is endorsed
For the test do we need to know how to derive the work equation? I know Dr. Lavelle said work and DU won't be on the test but this seems like a conceptual thing to me so I'm not entirely sure. I have this same question this is equation 4, and Lavelle said not to worry about it for test 1. But know ...
- Sun Jan 21, 2018 11:14 pm
- Forum: Phase Changes & Related Calculations
- Topic: Irreversible and Reversible
- Replies: 7
- Views: 720
Re: Irreversible and Reversible
reversible problems wont be on the test because that involves equation 4 on pg 266 and he said we dont need to worry about equation 4 for test 1
- Sun Jan 21, 2018 7:43 pm
- Forum: Phase Changes & Related Calculations
- Topic: Irreversible and Reversible
- Replies: 7
- Views: 720
Irreversible and Reversible
For test 1, will we need to know both irreversible and reversible or just one?
- Sun Jan 14, 2018 8:08 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Work
- Replies: 1
- Views: 158
Re: Work
Also what would be the steps to figure out the work?
- Sun Jan 14, 2018 8:08 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Work
- Replies: 1
- Views: 158
Work
How do you determine if there was work done or not? Not sure how to differentiate the differences.
- Sun Jan 14, 2018 8:03 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Most Staple Phases
- Replies: 3
- Views: 281
Re: Most Staple Phases
I believe some were:
Carbon = graphite
oxygen: O2
Chlorine: Cl2
Iodine: I2 (solid)
Br: Br2 (liquid)
Carbon = graphite
oxygen: O2
Chlorine: Cl2
Iodine: I2 (solid)
Br: Br2 (liquid)
- Sun Jan 14, 2018 7:59 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 3 Different Methods
- Replies: 2
- Views: 243
3 Different Methods
During lecture, Lavelle went over the different methods to solve enthalpy. How do you know when to use each method?
- Wed Nov 29, 2017 4:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T Shape or Trigonal Pyramidal
- Replies: 3
- Views: 546
Re: T Shape or Trigonal Pyramidal
thanks! That clears it up
- Wed Nov 29, 2017 10:40 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T Shape or Trigonal Pyramidal
- Replies: 3
- Views: 546
T Shape or Trigonal Pyramidal
How can I tell the difference between trigonal pyramidal and t shape when looking at the Lewis structures?
- Wed Nov 29, 2017 10:21 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 17.33
- Replies: 4
- Views: 986
Re: 17.33
lavelle has a chart of the polydentate that we should know about on his website if that helps
- Wed Nov 29, 2017 10:15 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: O3
- Replies: 2
- Views: 424
Re: O3
and is it polar or nonpolar?
- Wed Nov 29, 2017 10:14 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: O3
- Replies: 2
- Views: 424
O3
Is O3 linear or bent?
- Wed Nov 29, 2017 10:10 am
- Forum: Hybridization
- Topic: Trick for Hybridization
- Replies: 2
- Views: 274
Trick for Hybridization
What's a quick way or trick in finding the hybridization?
- Tue Nov 14, 2017 9:50 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: "more or less than 109.5 degrees"?
- Replies: 4
- Views: 1944
Re: "more or less than 109.5 degrees"?
when molecules have lone pairs, it is going push the atoms so that the angle will be narrower and less than expected
- Tue Nov 14, 2017 9:48 am
- Forum: Hybridization
- Topic: Homework Help: Problem 4.73
- Replies: 2
- Views: 395
Re: Homework Help: Problem 4.73
you should approach this problem as a trigonal pyramidal because with VSEPR formula is AX3E
- Tue Nov 07, 2017 10:48 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Midterm Q.5B
- Replies: 2
- Views: 636
Re: Midterm Q.5B
n=3 and l=2 does give 3d because l=2 implies the d orbital. The d orbital contains 5 orbitals with 2 e- in each orbital, making it have 10e-. I think you confused the number of orbitals and the number of maximum electrons.
- Tue Nov 07, 2017 10:34 am
- Forum: Quantum Numbers and The H-Atom
- Topic: 2.29 parts b and d
- Replies: 4
- Views: 656
Re: 2.29 parts b and d
Whenever I do questions like this I make this table to remind me of the of the l #, orbital, and electron amount l= orbital e- 0 s 2 1 p 6 2 d 10 3 f 14 so for b) because l=2, this problem has 2e- same for part d because l=2
- Tue Nov 07, 2017 10:27 am
- Forum: Ionic & Covalent Bonds
- Topic: Electron Configuration and d-block (3.11)
- Replies: 2
- Views: 411
Re: Electron Configuration and d-block (3.11)
also confused on this question...
- Wed Nov 01, 2017 11:50 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Which Quantum Number Represents What?
- Replies: 3
- Views: 779
Re: Which Quantum Number Represents What?
n -principal quantum number -determines the energy and size -also called shell n=1,2,3,4,... l -orbital angular momentum -describes the shape l=0,1,2,3.... (n-1) ml -labels different orbitals of a subshell -orientation -magnetism ml= -l -> +l above 3 quantum numbers specify an orbital ms -the spin m...
- Sun Oct 29, 2017 9:35 pm
- Forum: Lewis Structures
- Topic: HW 3.19 [ENDORSED]
- Replies: 4
- Views: 724
Re: HW 3.19 [ENDORSED]
To figure out if there is an unpaired electron, write out the electron configuration and/or orbital diagram.
- Mon Oct 23, 2017 9:42 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Confusion on e- Notes
- Replies: 2
- Views: 263
Confusion on e- Notes
I missed lecture, but I got notes from a friend and I noticed for the e- configuration for Cu it was written as: [Ar] 3d^104s^1
I was confused why there is a bracket around Ar? Is it just a shorter notation or way to write the configuration?
I was confused why there is a bracket around Ar? Is it just a shorter notation or way to write the configuration?
- Sun Oct 22, 2017 3:52 pm
- Forum: Photoelectric Effect
- Topic: Post Module #24
- Replies: 3
- Views: 381
Re: Post Module #24
The answer is UV because that part of the spectrum has a small wavelength with high frequency. And we know that high frequency allows for electrons to be ejected from the surface.
- Sat Oct 21, 2017 10:34 pm
- Forum: Photoelectric Effect
- Topic: Post Module #29 (KJ*mol^-1 problem)
- Replies: 4
- Views: 549
Re: Post Module #29 (KJ*mol^-1 problem)
yes, divide by Avogadro's constant. Then you can solve the rest of the question
- Sat Oct 14, 2017 9:13 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: H Equation [ENDORSED]
- Replies: 6
- Views: 702
Re: H Equation [ENDORSED]
I thought that too, but how would other elements apply to equations?
- Sat Oct 14, 2017 9:07 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: H Equation [ENDORSED]
- Replies: 6
- Views: 702
H Equation [ENDORSED]
Are we just focusing on equations for H or other elements too?
- Wed Oct 04, 2017 9:14 pm
- Forum: Empirical & Molecular Formulas
- Topic: Identifying Empirical and Molecular Formulas [ENDORSED]
- Replies: 13
- Views: 9015
Re: Identifying Empirical and Molecular Formulas [ENDORSED]
Empirical formula just gives the ratio/relative number of atoms
The molecular formula gives the actual number of atoms.
So the empirical formula would usually have a smaller ratio than the molecular formula
ex) C3H4O3 <-- empirical
C6H8O6 <-- molecular
The molecular formula gives the actual number of atoms.
So the empirical formula would usually have a smaller ratio than the molecular formula
ex) C3H4O3 <-- empirical
C6H8O6 <-- molecular
- Wed Oct 04, 2017 9:01 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig Figs
- Replies: 12
- Views: 3313
Sig Figs
I'm a little confused about sig figs. How many sig figs are in 460? and why do some questions have a number then a period after? ex. 898.