Search found 50 matches
- Fri Mar 16, 2018 10:23 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Functional Groups
- Replies: 1
- Views: 277
Functional Groups
I couldn’t make it to the review sessions covering functional groups, so can someone give me a run-down of how we are being expected to apply them on the exam?
- Fri Mar 16, 2018 10:20 pm
- Forum: First Order Reactions
- Topic: Reaction speed
- Replies: 1
- Views: 389
Reaction speed
I learned in one of the review sessions that for a first-order reaction, as k increases, the reaction speeds up. Is this true and does it apply to other reactions as well? I’m
- Fri Mar 16, 2018 10:10 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Question 14.41
- Replies: 6
- Views: 994
Re: Question 14.41
I’m also confused, since our notes say that we should always make the lower concentration the product
- Wed Mar 07, 2018 9:29 pm
- Forum: General Rate Laws
- Topic: Integrated Rate Laws
- Replies: 6
- Views: 819
Integrated Rate Laws
Are we being expected to derive integrated rate laws on the test or just use them?
- Wed Mar 07, 2018 3:15 am
- Forum: General Rate Laws
- Topic: Pg. 621 of textbook
- Replies: 1
- Views: 293
Pg. 621 of textbook
For the example regarding the oxidation of sulfur dioxide to sulfur trioxide in the presence of platinum, the textbook says that the reaction slows down as the concentration of SO3 increases. However, shouldn’t the reaction speed up because the fractional order of SO3 is 1/2?
- Wed Mar 07, 2018 2:56 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: k [ENDORSED]
- Replies: 2
- Views: 510
k [ENDORSED]
How exactly do we use the slope of a reaction graph to determine the rate constant k?
- Fri Mar 02, 2018 1:06 pm
- Forum: First Order Reactions
- Topic: First Order Graph
- Replies: 11
- Views: 1954
Re: First Order Graph
I believe it is linear and I actually thought it increased, but judging from previous comments, I’m probably mistaken
- Thu Mar 01, 2018 3:28 pm
- Forum: General Rate Laws
- Topic: Unique Rate [ENDORSED]
- Replies: 5
- Views: 831
Unique Rate [ENDORSED]
What defines the unique rate of a reaction?
- Wed Feb 28, 2018 9:09 pm
- Forum: General Rate Laws
- Topic: Average Rate of Consumption of R
- Replies: 1
- Views: 294
Average Rate of Consumption of R
On page 612 of the textbook, why is the average rate of consumption of R negative?
- Mon Feb 26, 2018 12:57 pm
- Forum: Balancing Redox Reactions
- Topic: Recognizing a redox reaction in acidic or basic solution
- Replies: 5
- Views: 632
Re: Recognizing a redox reaction in acidic or basic solution
If I remember correctly, we were always told whether the reaction was acidic or basic in the textbook, so I assume it will be like that on the exam as well
- Mon Feb 26, 2018 12:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge [ENDORSED]
- Replies: 2
- Views: 402
Re: Salt Bridge [ENDORSED]
I read somewhere that the porous membrane is inside the salt bridge to allow charged ions to flow between the cells, but the salt bridge keeps the water contained
- Wed Feb 21, 2018 10:43 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation number
- Replies: 1
- Views: 203
Oxidation number
I know determining oxidation numbers was covered in 14A, but can someone remind me on how to do so when balancing redox reactions?
- Wed Feb 14, 2018 1:26 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: heat vs thermal energy [ENDORSED]
- Replies: 2
- Views: 426
heat vs thermal energy [ENDORSED]
What’s the difference between being asked to calculate the amount of thermal energy versus the amount of heat required to raise a substance to a certain temperature?
- Mon Feb 12, 2018 6:35 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Joe’s Review Session Last Problem
- Replies: 1
- Views: 305
Joe’s Review Session Last Problem
Can someone who went to Joe’s review session tonight give me a breakdown of the steps to calculate the last problem calculating deltaG using numbers as well please? Thank you!
- Mon Feb 12, 2018 6:22 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Joe’s Review Session
- Replies: 1
- Views: 309
Joe’s Review Session
For anyone who went to Joe’s review session today, can someone give me a run-through on the steps to solve the problem he gave us with calculating the total deltaS for vaporization of C2H5OH, including the numbers you got for each step? I keep getting the wrong answer and I’m not sure why. I believe...
- Sat Feb 10, 2018 6:02 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: When to use + sign
- Replies: 11
- Views: 1062
Re: When to use + sign
I think even if the solution should manual doesn’t always use the + sign, it would be preferable to use it for tests/exams
- Sat Feb 10, 2018 5:46 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 9.13
- Replies: 4
- Views: 505
Re: 9.13
I’m not completely sure, but I feel like it might have something to do with it having to be in standard state because it says “Assume ideal behavior.” Someone correct me if I’m wrong
- Tue Feb 06, 2018 2:56 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Calculating deltaG
- Replies: 2
- Views: 297
Calculating deltaG
There are 3 different equations to calculate deltaG. When do we use each of them?
- Fri Feb 02, 2018 1:47 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs “Available” energy
- Replies: 2
- Views: 367
Gibbs “Available” energy
Under what conditions did Dr. Lavelle mention that the energy available to do work is considered Gibbs free energy?
- Fri Feb 02, 2018 1:43 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: reversible and irreversible with entropy
- Replies: 2
- Views: 382
Re: reversible and irreversible with entropy
I believe we only use it for reversible reactions, but someone correct me if I’m wrong
- Fri Feb 02, 2018 1:38 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: How do we find out if a system is favorable? [ENDORSED]
- Replies: 7
- Views: 4996
Re: How do we find out if a system is favorable? [ENDORSED]
I’m not completely sure, but I vaguely remembering him saying spontaneous processes are favorable, but correct me if I’m wrong
- Mon Jan 29, 2018 12:57 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: reversible vs. irreversible [ENDORSED]
- Replies: 2
- Views: 309
Re: reversible vs. irreversible [ENDORSED]
In short, reversible processes do more work than irreversible processes because it is exerting work upon a higher external pressure.
- Wed Jan 24, 2018 11:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Exercise 8.39
- Replies: 2
- Views: 218
Exercise 8.39
As seen in the solutions manual, where did the 6.01 kJ.mol^-1 come from?
- Wed Jan 24, 2018 12:56 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Exercise 8.19
- Replies: 1
- Views: 182
Exercise 8.19
If we encounter a problem such as 19, will we be given the heat capacity for elements such as copper?
- Sat Jan 20, 2018 4:16 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Specific Heat Capacity
- Replies: 3
- Views: 435
Specific Heat Capacity
On page 269 of the textbook, it says the units for specific heat capacity is J. degrees Celsius^-1. g^-1, or J. K^-1. g^-1. Does the K stand for Kelvin and if so, how is that equivalent to degrees Celsius?
- Sat Jan 20, 2018 2:53 pm
- Forum: Calculating Work of Expansion
- Topic: Formula for reversible expansion
- Replies: 2
- Views: 194
Formula for reversible expansion
What does the R represent in the formula for reversible expansion?
- Thu Jan 18, 2018 2:27 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Exercise 8.7
- Replies: 2
- Views: 282
Exercise 8.7
Why is it that the answer is written as +4.90 x 10^2 J instead of kept as 490 J?
- Sat Jan 13, 2018 8:29 pm
- Forum: Phase Changes & Related Calculations
- Topic: Constant temp
- Replies: 3
- Views: 304
Re: Constant temp
The temperature remains constant because the heat being supplied is used up to initiate the phase transition, aka to melt/boil.
- Sat Jan 13, 2018 8:16 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sig Figs for Question 8.45 (a)
- Replies: 5
- Views: 524
Re: Sig Figs for Question 8.45 (a)
Dr. Lavelle has mentioned in class before that his method is to round to the nearest even number if it ends in a 5, so I would assume that is the way he would prefer it to be on exams/tests. I doubt you would get docked off points for rounding it to 449 though.
- Sat Jan 13, 2018 8:10 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: enthalpy vs heat
- Replies: 2
- Views: 435
Re: enthalpy vs heat
I think the most simple way to think of it is that enthalpy is determined by the amount of heat released or absorbed, rather than by the substance heat itself.
- Sat Dec 09, 2017 12:14 am
- Forum: Hybridization
- Topic: Hybridization
- Replies: 2
- Views: 241
Hybridization
Can someone please summarize for me how to determine what kind of hybridization an element in a compound goes through? I’m just lost and need a step-by-step break down
- Fri Dec 08, 2017 7:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity
- Replies: 1
- Views: 234
Polarity
How can I determine if a compound is polar or nonpolar from its molecular shape?
- Thu Nov 30, 2017 2:05 am
- Forum: Ideal Gases
- Topic: Temperature in PV=nRT
- Replies: 9
- Views: 1136
Temperature in PV=nRT
What is the unit we should be using for temperature in PV=nRT?
- Wed Nov 29, 2017 9:45 pm
- Forum: Naming
- Topic: Oxidation State [ENDORSED]
- Replies: 2
- Views: 451
Oxidation State [ENDORSED]
How do I determine the oxidation state of a coordination compound?
- Sun Nov 26, 2017 1:16 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs vs. Bonding Pairs
- Replies: 6
- Views: 922
Re: Lone Pairs vs. Bonding Pairs
A possible reason why is that because a bonding pair is held in place by two atoms, its electron cloud can not spread over as large of a volume as a lone pair can. (Textbook pg.21)
- Sun Nov 26, 2017 1:14 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Equitorial vs. Axial Lone Pair
- Replies: 2
- Views: 600
Re: Equitorial vs. Axial Lone Pair
Just to add on to the previous response, you want there to be the least amount of repulsion and energy where the lone pair is placed. I’m an equatorial position, it is only close to two atoms, versus three atoms in an axial position, so the former is the ideal arrangement.
- Sun Nov 26, 2017 1:10 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Formula
- Replies: 3
- Views: 3106
VSEPR Formula
Why is it that molecules with the same general VSEPR formula can still differ in angle degrees?
- Thu Nov 16, 2017 2:47 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Exercise 4.7 and 4.9
- Replies: 2
- Views: 252
Exercise 4.7 and 4.9
I am confused as to why 4.7 is a trigonal pyramidal but 4.9 is not? I have a feeling it has something to do with electron repulsion, but I don't quite understand it fully.
- Thu Nov 09, 2017 2:02 pm
- Forum: Resonance Structures
- Topic: Resonance Structures for the Midterm
- Replies: 3
- Views: 611
Re: Resonance Structures for the Midterm
The questions will be very specific, either asking you to draw the most stable structure or just one resonance structure, etc.
- Thu Nov 09, 2017 1:55 pm
- Forum: DeBroglie Equation
- Topic: Photons? [ENDORSED]
- Replies: 4
- Views: 566
Re: Photons? [ENDORSED]
Yes, so if you are trying to find the wavelength of an ejected electron, you must use the De Brogile equation an its momentum. You cannot use E = hv and other extensions of it.
- Wed Nov 01, 2017 4:16 pm
- Forum: Properties of Electrons
- Topic: Schrodinger's Equation [ENDORSED]
- Replies: 1
- Views: 372
Schrodinger's Equation [ENDORSED]
Can someone please summarize the key points of section 2.1? I am confused about the relationship of Schrodinger's equation to wave functions and orbitals. Also, on the outline, what does it mean by the interpretation of atomic orbitals in terms of probability? Sorry that's quite a few questions, but...
- Wed Nov 01, 2017 1:43 am
- Forum: Properties of Electrons
- Topic: Ground State
- Replies: 5
- Views: 672
Ground State
How do we know when the electrons in an atom are in its ground state judging from the spins and orbitals?
- Thu Oct 26, 2017 12:36 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Unpaired Electrons [ENDORSED]
- Replies: 1
- Views: 199
Unpaired Electrons [ENDORSED]
How do I know how many unpaired electrons an element atom has based on its electron configuration?
- Wed Oct 25, 2017 7:18 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Exercise 1.45
- Replies: 4
- Views: 630
Exercise 1.45
For exercise 45 of chapter 1 regarding the Heisenberg Indeterminacy, the problem tells us that the bowling ball is rolled at 5.00 +/- 5.0 m.s^-1. What does the +/- part tell us and what do we do with that in our work? I noticed that the solutions manual only uses 5.0 m/s^-1, so I am not sure where t...
- Sat Oct 21, 2017 12:34 am
- Forum: Properties of Electrons
- Topic: Electron Configuration [ENDORSED]
- Replies: 3
- Views: 614
Electron Configuration [ENDORSED]
Just to be sure, on the test, will we get marked down points if we only indicate the P state on its own instead of specifically notating Px, Py, and Pz?
- Sat Oct 21, 2017 12:29 am
- Forum: Properties of Electrons
- Topic: Ending Frequency [ENDORSED]
- Replies: 3
- Views: 609
Re: Ending Frequency [ENDORSED]
I am not sure if I understood your question correctly, so feel free to give feedback and elaborate. Which light are you trying to calculate the frequency for? If it's the incoming light that hits the electron, then you use the given total energy of that incoming light or the energy that you calculat...
- Fri Oct 13, 2017 4:25 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: why is Bohr Frequency equation negative
- Replies: 4
- Views: 1865
Re: why is Bohr Frequency equation negative
To sum it up, I believe that the negative sign represents the idea that the energy being used to remove the electron (a positive value) must match and thus cancel out the negative value of the required energy to move the electron. As the electron moves from a higher to lower energy level, the energy...
- Fri Oct 13, 2017 4:07 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Bohr Frequency Equation
- Replies: 1
- Views: 520
Bohr Frequency Equation
Can someone please explain to me what the Bohr frequency equation tells us? In the lecture, I heard something about two things needing to match up with each other, but I did not quite understand it. Thanks in advance!
- Fri Oct 06, 2017 1:10 am
- Forum: SI Units, Unit Conversions
- Topic: Significant Figures [ENDORSED]
- Replies: 9
- Views: 2113
Significant Figures [ENDORSED]
Based on a problem, how do we know how many sig figs we should round to?
- Thu Oct 05, 2017 7:21 pm
- Forum: SI Units, Unit Conversions
- Topic: Exercise E35
- Replies: 2
- Views: 381
Exercise E35
I believe that the formula for calculating percent change is the original subtracted from the result, divided by the original value. The original value in this problem should be the mass of hydroxyapatite, 502.31 g/mol, but the solutions manual divides the difference by the latter value of flourapat...