When does Delta H=q?
Delta H=w?
If ever.
Search found 63 matches
- Fri Mar 15, 2019 11:44 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: rules for Delta H
- Replies: 1
- Views: 380
- Fri Mar 15, 2019 11:43 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Rules for delta U
- Replies: 2
- Views: 515
Rules for delta U
When is delta U=0?
delta U=q?
delta U=q?
- Fri Mar 15, 2019 11:42 am
- Forum: First Order Reactions
- Topic: Exponents for rate laws
- Replies: 1
- Views: 233
Exponents for rate laws
What determines the exponent for rate laws, the coefficient (like in equilibrium), or the order?
- Fri Mar 15, 2019 11:41 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Delta N
- Replies: 1
- Views: 334
Delta N
To solve for Delta n is it moles of the product minus moles of the reactant?
- Fri Mar 15, 2019 11:40 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy At Constant Volume?
- Replies: 2
- Views: 400
Enthalpy At Constant Volume?
Does Enthalpy exist at a constant volume?
- Sun Mar 03, 2019 8:51 pm
- Forum: First Order Reactions
- Topic: homework problems
- Replies: 2
- Views: 200
homework problems
Which homework problems are applicable to this chapter? Week 9?
- Wed Feb 27, 2019 7:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Phases used in a Galvanic Cell
- Replies: 3
- Views: 357
Phases used in a Galvanic Cell
Are solids, gases, and aqueous the only phases used on a cell diagram? Are liquids never listed?
- Wed Feb 27, 2019 11:39 am
- Forum: General Science Questions
- Topic: Test 2 7th edition book
- Replies: 1
- Views: 567
Test 2 7th edition book
what homework questions does test 2 cover from the seventh edition book?
- Sun Feb 24, 2019 5:13 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Determining what is constant
- Replies: 1
- Views: 224
Determining what is constant
How do you decide what is at a constant with out it being said. I have run into questions that don't talk about volume then the answer seems to imply that is is constant. How is this determined? Are there any rules informing you on how to decide? What happens if nothing is stated?
- Sun Feb 24, 2019 5:10 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Relation to Enthalpy and Entropy
- Replies: 4
- Views: 1541
Relation to Enthalpy and Entropy
How are Gibb's Free Energy, Work, Enthalpy and Entropy related?? is this significant?
- Sun Feb 24, 2019 5:09 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Spontaneous?
- Replies: 6
- Views: 714
Spontaneous?
How do you determine if Gibbs free energy is spontaneous or not?
- Fri Feb 22, 2019 2:43 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Porous Disc
- Replies: 2
- Views: 315
Porous Disc
I am confused on the porous disk that keeps being referred to in class. What is the difference between a porous disc and a salt bridge?
- Fri Feb 22, 2019 2:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cathode vs. Anode
- Replies: 9
- Views: 776
Cathode vs. Anode
What are the rules for determining which is a cathode and which is an anode?
- Fri Feb 22, 2019 2:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Homework Questions on Test 2
- Replies: 1
- Views: 238
Homework Questions on Test 2
What sections of homework should we be looking at for test 2?
- Thu Feb 14, 2019 10:53 am
- Forum: General Science Questions
- Topic: Midterm Formulas
- Replies: 6
- Views: 953
Re: Midterm Formulas
Most of the formulas that are not provided can be derived from the ones given.
- Tue Feb 12, 2019 4:23 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: When does delta U equal zero?
- Replies: 17
- Views: 8221
When does delta U equal zero?
What are the rules for delta U = 0? When does this happen? Under what circumstances?
- Tue Feb 12, 2019 4:22 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Homework Questions
- Replies: 2
- Views: 370
Midterm Homework Questions
For the 7th edition of the textbook what is the last section that will be covered on the midterm?
- Fri Feb 08, 2019 7:05 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: ideal gas volume
- Replies: 1
- Views: 228
Re: ideal gas volume
Is this just having to do with constant volume or would it also be constant temp or pressure?
- Fri Feb 08, 2019 7:03 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Study Guides
- Replies: 15
- Views: 1192
Re: Study Guides
Are there study guides posted for the thermo chem information?
- Fri Feb 08, 2019 7:01 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Ideal Gas Laws
- Replies: 4
- Views: 567
Ideal Gas Laws
What are the rules and equations that go with ideal gases? Are idea gases noble gases?
- Thu Jan 31, 2019 11:04 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Phase changes and enthaplies
- Replies: 3
- Views: 355
Phase changes and enthaplies
How are phase changes and enthalpies related? Does it have to do with exothermic and endothermic reactions?
- Thu Jan 31, 2019 11:02 am
- Forum: Phase Changes & Related Calculations
- Topic: What Does U and q stand for?
- Replies: 9
- Views: 2250
What Does U and q stand for?
In many of the problems in the homework there were equations with U and q. What do these variables stand for?
- Thu Jan 31, 2019 11:01 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: closed vs isolated
- Replies: 14
- Views: 1002
Re: closed vs isolated
I always think of an isolated system like a closed hydroflask compared to a closed water bottle. The hydroflask has layers of steel around it and truly isolates whats inside.
- Wed Jan 23, 2019 11:52 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Acids and Bases
- Replies: 6
- Views: 536
Re: Acids and Bases
Becky Belisle 1A wrote:It depends on which defintion you use. A Bronsted acid donates a proton, so it must at least have a proton in the formula.
Which definition should we be using to determine if something is an acid or a base?
- Wed Jan 23, 2019 11:50 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5% rule and % ionization
- Replies: 2
- Views: 343
5% rule and % ionization
What are the steps for solving for a percent ionized/deprotonized question and how does that relate to the 5% rule?
- Wed Jan 23, 2019 11:47 am
- Forum: Ideal Gases
- Topic: The Difference between Q and Kc [ENDORSED]
- Replies: 18
- Views: 8567
Re: The Difference between Q and Kc [ENDORSED]
Q is the same equation as K, but Q is calculated at anytime during the reaction and compared to K. If K and Q match then the system is at equilibrium. If Q<K it moves towards the products, if Q>K it moves towards the reactants.
- Wed Jan 16, 2019 8:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Test Topics for Week 3 [ENDORSED]
- Replies: 1
- Views: 270
Test Topics for Week 3 [ENDORSED]
What equations are going to be needed for this upcoming test?
- Wed Jan 16, 2019 8:54 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Tricks for ICE tables
- Replies: 5
- Views: 480
Tricks for ICE tables
Are there any tricks for knowing when to use an ICE table?
- Wed Jan 16, 2019 8:54 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Acid and Base Equilibria
- Replies: 7
- Views: 632
Re: Acid and Base Equilibria
If you are saying higher pH in terms of numbers closer to 7 than yes you would be correct. If you think about a strong acid that has completely dissociated, the humber of H+ ions in that solution will be greater than that of a weak acid.
- Thu Jan 10, 2019 11:12 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K=1
- Replies: 5
- Views: 358
Re: K=1
I think about like a proportion. So if there are 3 particles of reactant there has to be 3 particles of products. Dividing those numbers would equal 1.
- Thu Jan 10, 2019 11:08 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K
- Replies: 4
- Views: 399
Re: K
I believe each K (other than Keq) has units but when it is placed into the equation the units are no longer needed.
- Thu Jan 10, 2019 11:06 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Why Would Equilibrium cause death in humans?
- Replies: 3
- Views: 3122
Why Would Equilibrium cause death in humans?
I do not understand the concept that a human becoming at equilibrium means they are dead? Why would that be?
- Tue Dec 04, 2018 7:53 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Identifying the Different Types of Acidic and Bases
- Replies: 2
- Views: 145
Identifying the Different Types of Acidic and Bases
I know there are Lewis acids and bases and Bronsted bases and acids, are there anymore we should know? Also, what are the differences between them?
- Tue Dec 04, 2018 7:49 pm
- Forum: General Science Questions
- Topic: Chemistry Community [ENDORSED]
- Replies: 7
- Views: 815
Re: Chemistry Community [ENDORSED]
I believe thats how it will work, and I don't think we have to post the week.
- Tue Dec 04, 2018 7:34 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Rules for acidic & basic salts
- Replies: 1
- Views: 174
Rules for acidic & basic salts
Are there any specific rules that apply only to acidic and basic salts? Along with this are there specific calculations for acidic and basic salts?
- Fri Nov 30, 2018 10:23 pm
- Forum: Sigma & Pi Bonds
- Topic: Rotating Bond?
- Replies: 4
- Views: 675
Rotating Bond?
I remember Dr. Lavelle talking about either sigma or pi bonds being able to rotate, which one was it? Thank you!
- Thu Nov 29, 2018 10:45 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Determining Dipoles
- Replies: 2
- Views: 287
Determining Dipoles
How do you determine the dipole direction and sign on a molecule?
- Wed Nov 28, 2018 4:09 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Exam topic
- Replies: 1
- Views: 91
Exam topic
Is it necessary that we know VSEPR shape formulas for the exam?
- Wed Nov 28, 2018 4:05 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar covalent vs. polar ionic bonds
- Replies: 1
- Views: 282
Polar covalent vs. polar ionic bonds
What exactly is the difference between polar ionic bonds and polar covalent bonds?
- Wed Nov 28, 2018 4:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarizability
- Replies: 2
- Views: 323
Polarizability
I am still a bit confused on how to find the polarizability of and ion and what exactly polarizability is. If anyone could help that would be great! Thank you!
- Wed Nov 28, 2018 4:00 pm
- Forum: Hybridization
- Topic: Polar Power
- Replies: 5
- Views: 451
Polar Power Compared to Atomic Radius
Is the polar power only determined by the atomic radius? For this would it be the smaller the radius the larger the polar power?
- Tue Nov 13, 2018 4:39 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: Shape and Boiling Point
- Replies: 12
- Views: 3015
Re: Shape and Boiling Point
Does the distance between the bonds effect the boiling point? Would this cause the bond to be stronger or weaker?
- Tue Nov 13, 2018 4:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Homework for VSEPR
- Replies: 3
- Views: 353
Homework for VSEPR
In terms of homework problems for this week which questions would be the most applicable? Which section would be the best to help learn VSEPR structures?
- Tue Nov 13, 2018 4:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3
- Replies: 8
- Views: 1701
Re: Test 3
Is anyone aware is test 3 is next week? what happens if our discussion is over break?
- Wed Nov 07, 2018 10:16 pm
- Forum: Bond Lengths & Energies
- Topic: Special Bond Length Rules
- Replies: 3
- Views: 420
Special Bond Length Rules
Are there any special bond length rules? Let me know any information is appreciated!!
- Wed Nov 07, 2018 10:02 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionization Energies
- Replies: 13
- Views: 3571
Re: Ionization Energies
Remember that Ionization energy is how much energy it takes to create an ion from a stable molecule. This will be very high for noble gases, because they are so stable.
- Sun Nov 04, 2018 6:40 pm
- Forum: Properties of Electrons
- Topic: Frequency of an electron equation
- Replies: 2
- Views: 540
Frequency of an electron equation
I know that there are specific equations that you can only use for an electron or something with mass. Which equation would you use to find the frequency of an electron?
- Tue Oct 30, 2018 10:14 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Key Words
- Replies: 4
- Views: 478
Key Words
Hey!! I'm just wondering if anyone has any keywords and definitions that would help us study for the midterm??
- Tue Oct 30, 2018 10:09 pm
- Forum: *Black Body Radiation
- Topic: Midterm
- Replies: 4
- Views: 626
Re: Midterm
There are study questions posted on here too and they seem to cover most of the main topics so i would use that as a guideline.
- Tue Oct 30, 2018 10:06 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Electron Spin
- Replies: 3
- Views: 1095
Re: Electron Spin
In terms of this rule is the up arrow electron positive or negative 1/2?
- Tue Oct 23, 2018 10:27 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Is there ever a negative frequency
- Replies: 1
- Views: 256
Is there ever a negative frequency
For Rydberg's equation should the answer ever be negative? What if you go from n=4 to n=2 or n=3 to n=5?
- Tue Oct 23, 2018 10:25 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 7
- Views: 674
Re: Rydberg Equation
I was running into the same problem. I'm not sure but is the answer ever supposed to be negative?
- Tue Oct 23, 2018 10:23 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Relationship Between Equations
- Replies: 1
- Views: 284
Relationship Between Equations
What is the relationship between En= -hR/n2 and Rydberg's equation?
- Tue Oct 23, 2018 10:09 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 7
- Views: 674
Rydberg Equation
I have been looking around and I can't find a clear answer to tell me if in the Rydberg equation it is R((1/(the original value of n))-(1/(the final value of n)) or the opposite way for the final and initial values. Please let me know if you can! Thank you!
- Tue Oct 16, 2018 11:02 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Heisenberg's Indeterminacy Equation
- Replies: 3
- Views: 239
Heisenberg's Indeterminacy Equation
For Heisenberg's Indeterminacy Equation we have to find either delta p or delta v. What are the definitions of delta p and delta v so i know which variable a given value falls under? This value would then be placed in the equation and solved.
- Tue Oct 16, 2018 10:54 am
- Forum: Properties of Light
- Topic: Vocab
- Replies: 5
- Views: 452
Re: Vocab
When you say "discrete values" does that mean it can only have one value at a time or just a small range of values?
- Tue Oct 16, 2018 10:48 am
- Forum: Properties of Light
- Topic: Week 3 HW
- Replies: 5
- Views: 520
Re: Week 3 HW
I believe that it would be helpful to do both Ch 1 and Ch 2, since we have a test next week. The seven problems will be due in your discussion section, too.
- Tue Oct 09, 2018 10:20 am
- Forum: Significant Figures
- Topic: Sig Fig zero rules
- Replies: 7
- Views: 2322
Sig Fig zero rules
Hello! i am having some trouble remembering how sig figs work with zeros. For example how many sig figs are in 570, 500, 4.0, 40.0, .04, 0.04, .40, .0040? if anyone could help me out with this that would be greatly appreciated. Also if there are any other tricks for knowing how many sig figs there a...
- Tue Oct 09, 2018 10:09 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Finding the volume of stock solution to dilute
- Replies: 13
- Views: 1246
Re: Finding the volume of stock solution to dilute
Hello! I'm don't think it is completely necessary to convert your answers to mL from Liters, but I usually do since there are sometimes other steps to the problem where you are subtracting a volume from a greater volume and in this case they would both need to have matching units.
- Tue Oct 09, 2018 10:02 am
- Forum: Properties of Light
- Topic: Exam
- Replies: 7
- Views: 622
Re: Exam
The way I have been looking at it is first reviewing the problems that we did in our discussions. Those seem to have many important features. Next I am going to watch the audio videos and take notes. The pre and post assessments i am going to use to gauge my understanding of the concepts and then ad...
- Tue Oct 02, 2018 3:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Do we have to write out the question for homework?
- Replies: 4
- Views: 477
Re: Do we have to write out the question for homework?
I have been writing at least part of the question out on the homework. I find that if helps me review and remember what the question was asking without going all the way back into the book.
- Tue Oct 02, 2018 3:01 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity and Mass
- Replies: 2
- Views: 142
Re: Molarity and Mass
First you take molarity and multiply it by liters. Then you that the value in mols that you are left with and multiply that by grams/mole. Finally you are left with grams.
- Tue Oct 02, 2018 2:59 pm
- Forum: SI Units, Unit Conversions
- Topic: Textbook Homework Assignment
- Replies: 11
- Views: 1347
Re: Textbook Homework Assignment
The seventh edition starts with pages like F1. The question that we are supposed to answer are usually at the end of each letter sub section. Once the F pages end the pages are only labeled by numbers.