Search found 53 matches

Thu Mar 15, 2018 10:18 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Negative Ea
Replies: 3
Views: 237

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: 163

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: 565

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: 292

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: 195

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: 565

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: 475

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: 239

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: 347

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: 399

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: 314

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: 163

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: 356

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
Sat Mar 03, 2018 11:41 am
Forum: General Rate Laws
Topic: Calculating Rate vs. Unique Average Rate
Replies: 2
Views: 170

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: 460

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: 460

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: 379

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: 278

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: 198

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: 291

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: 198

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: 287

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: 364

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: 752

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: 246

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: 214

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: 2902

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: 401

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: 401

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: 108

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: 108

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: 157

Re: Most Staple Phases

I believe some were:

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: 129

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: 275

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: 275

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: 565

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: 251

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: 251

O3

Is O3 linear or bent?
Wed Nov 29, 2017 10:10 am
Forum: Hybridization
Topic: Trick for Hybridization
Replies: 2
Views: 169

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: 602

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: 200

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: 442

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: 434

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: 245

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: 501

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: 452

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: 200

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?
Sun Oct 22, 2017 3:52 pm
Forum: Photoelectric Effect
Topic: Post Module #24
Replies: 3
Views: 252

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: 293

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: 503

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: 503

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: 5424

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
Wed Oct 04, 2017 9:01 pm
Forum: SI Units, Unit Conversions
Topic: Sig Figs
Replies: 12
Views: 1197

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.