## Search found 50 matches

Fri Mar 16, 2018 10:23 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Functional Groups
Replies: 1
Views: 145

### 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: 225

### 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: 455

### 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: 372

### 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: 117

### 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: 252

### 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: 615

### 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: 394

### 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: 131

### 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: 302

### 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: 191

### 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: 95

### 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: 211

### 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: 156

### 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: 153

### 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: 524

### 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: 212

### 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: 150

### 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: 127

### 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: 187

### 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: 2142

### 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: 132

### 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: 101

### 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: 122

### 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: 212

### 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: 116

### 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: 207

### 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: 207

### 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: 301

### 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: 202

### 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: 192

### 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: 163

### 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: 638

### 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: 246

### 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: 477

### 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: 348

### 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: 1602

### 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: 175

### 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: 380

### 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: 332

### 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: 208

### 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: 415

### 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: 141

### 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: 352

### 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: 403

### 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: 409

### 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: 882

### 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: 281

### 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: 1145

### 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: 295

### 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...