Search found 66 matches
- Sun Mar 10, 2019 7:34 pm
- Forum: General Rate Laws
- Topic: rate of reaction formula
- Replies: 1
- Views: 201
rate of reaction formula
the solution manual shows that the equation for rate of reaction is: - (deltaConcentration) / (deltaTime). Why is there a negative in the equation/formula?? This is the problem im referring to: 15.3 6th ed. In 20. s, the concentration of nitrogen dioxide, NO2, decreases from 450 mmol/L to 320 mmol/L...
- Mon Feb 25, 2019 3:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: 11.83 6th ed // delta G equation [ENDORSED]
- Replies: 1
- Views: 233
11.83 6th ed // delta G equation [ENDORSED]
for 11.83 we need the delta G value, the solution manual uses deltaG=deltaH - T* deltaS using values from appendix 2A, but can’t we just use the deltaG values from appendix 2A and use the deltaG= sum(deltaG products) - sum(deltaG reactants) ??? is there a reason they’re using the deltaH and deltaS t...
- Mon Feb 25, 2019 3:10 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: standard vs reaction gibbs free energy [ENDORSED]
- Replies: 3
- Views: 339
Re: standard vs reaction gibbs free energy [ENDORSED]
more specifically i’m referring to questions 11.15 and 11.21 6th ed, they’re the same reaction occurring at the same temp, but one asks for the standard gibbs (and gives the k value only) while the other asks for the reaction gibbs (giving both k and the partial pressures). so what i’m understand is...
- Mon Feb 25, 2019 1:45 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: gibbs and temperature, 9.67 6th ed
- Replies: 5
- Views: 577
- Mon Feb 25, 2019 1:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: standard vs reaction gibbs free energy [ENDORSED]
- Replies: 3
- Views: 339
standard vs reaction gibbs free energy [ENDORSED]
What’s the difference between standard gibbs free energy and reaction gibbs free energy?
- Sun Feb 24, 2019 5:13 pm
- Forum: Student Social/Study Group
- Topic: How are you guys going to study for Test 2?
- Replies: 10
- Views: 915
Re: How are you guys going to study for Test 2?
review the hw problems!!
- Sun Feb 24, 2019 5:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2
- Replies: 7
- Views: 810
Re: Test 2
Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:10 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Test 2 Help
- Replies: 7
- Views: 702
Re: Test 2 Help
test 2 is Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Quiz 3
- Replies: 3
- Views: 331
Re: Quiz 3
Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:09 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy at 0 K
- Replies: 4
- Views: 724
Re: Entropy at 0 K
are we assuming temperature is never below 0K?
- Sun Feb 24, 2019 5:08 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: test 3
- Replies: 10
- Views: 931
Re: test 3
do you mean test 2? Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:07 pm
- Forum: Balancing Redox Reactions
- Topic: Week 7 worksheet (2E, I, K)
- Replies: 4
- Views: 738
Re: Week 7 worksheet (2E, I, K)
thank you so much!!
- Sun Feb 24, 2019 5:07 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test 3
- Replies: 14
- Views: 2243
Re: Test 3
do you mean test 2? Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:06 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Material
- Replies: 11
- Views: 862
Re: Test 2 Material
Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:06 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: gibbs free energy
- Replies: 5
- Views: 571
Re: gibbs free energy
In thermodynamics, the Gibbs free energy is a thermodynamic potential that can be used to calculate the maximum of reversible work that may be performed by a thermodynamic system at a constant temperature and pressure.
- Sun Feb 24, 2019 5:05 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test 2
- Replies: 9
- Views: 1033
Re: Test 2
it covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7)
- Sun Feb 24, 2019 5:04 pm
- Forum: Administrative Questions and Class Announcements
- Topic: What topics are going to be on Test 2?
- Replies: 4
- Views: 431
Re: What topics are going to be on Test 2?
Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7).
- Sun Feb 24, 2019 5:04 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Test 2
- Replies: 4
- Views: 474
Re: Test 2
it covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation
- Sun Feb 24, 2019 5:04 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Material
- Replies: 13
- Views: 1245
Re: Test 2 Material
Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7).
- Sun Feb 24, 2019 5:02 pm
- Forum: Balancing Redox Reactions
- Topic: TEST
- Replies: 7
- Views: 812
Re: TEST
Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7).
- Sun Feb 24, 2019 5:02 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Regrades
- Replies: 2
- Views: 344
Re: Midterm Regrades
talk to your TA, depending on the problem usually either they can help you with it
- Sun Feb 24, 2019 5:00 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: gibbs and temperature, 9.67 6th ed
- Replies: 5
- Views: 577
gibbs and temperature, 9.67 6th ed
I'm a little confused, for number 9.67 in the 6th edition it says: Assume that deltaH and deltaS are independent of temp and use data from appendix 2a to calculate deltaG for each of the following reactions at 80C. Over what temperature range will each of the reactions be spontaneous under standard ...
- Thu Jan 31, 2019 2:44 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: understanding calculating reaction enthalpy
- Replies: 2
- Views: 354
Re: understanding calculating reaction enthalpy
The standard enthalpy of formation is defined as the change in enthalpy when one mole of a substance in the standard state (1 atm of pressure and 298.15 K) is formed from its pure elements under the same conditions.
- Thu Jan 31, 2019 2:43 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Enthalpy
- Replies: 4
- Views: 566
Re: Standard Enthalpy
All elements in their standard states (oxygen gas, solid carbon in the form of graphite, etc.) have a standard enthalpy of formation of zero, as there is no change involved in their formation.
- Thu Jan 31, 2019 2:42 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Isolated systems
- Replies: 10
- Views: 710
Re: Isolated systems
An isolated system is a thermodynamic system that cannot exchange either energy or matter outside the boundaries of the system. An isolated system differs from a closed system by the transfer of energy. Closed systems are only closed to matter, energy can be exchanged across the system's boundaries.
- Thu Jan 31, 2019 2:41 pm
- Forum: Ideal Gases
- Topic: breaking bond - heat released and gained
- Replies: 5
- Views: 847
Re: breaking bond - heat released and gained
Breaking Bonds Requires Energy. You have to put energy into a molecule to break its chemical bonds. The amount needed is called the bond energy.
- Thu Jan 31, 2019 2:40 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Homework
- Replies: 9
- Views: 854
Re: Homework
a lot of the questions tend to jump around if you're following what we learn in class, but by the end of the chapter we usually have covered all the topics
- Thu Jan 31, 2019 2:39 pm
- Forum: Ideal Gases
- Topic: atm vs. bar?
- Replies: 25
- Views: 2714
Re: atm vs. bar?
they are both units of measurement for pressure and depending on your TA, both should be fine to use
- Wed Jan 16, 2019 10:22 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic vs. Endothermic Reaction
- Replies: 9
- Views: 3111
Re: Exothermic vs. Endothermic Reaction
A quick difference between endothermic and exothermic involves reactions in the environment. An endothermic reaction takes place when energy is absorbed from surroundings in the form of heat, and exothermic is when energy is released from the system into the surroundings.
- Wed Jan 16, 2019 10:20 am
- Forum: Ideal Gases
- Topic: Homework for week 2 [ENDORSED]
- Replies: 10
- Views: 2927
Re: Homework for week 2 [ENDORSED]
week two can be either outline 1 or 2
- Wed Jan 09, 2019 1:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What does it mean when a reaction is at equilibrium?
- Replies: 4
- Views: 423
Re: What does it mean when a reaction is at equilibrium?
the rates of product changing to reactants and reactants changing to products are the same
- Wed Jan 09, 2019 1:06 pm
- Forum: Ideal Gases
- Topic: Q and K [ENDORSED]
- Replies: 35
- Views: 2931
Re: Q and K [ENDORSED]
the formulas are the same, K is at equillibrium
- Wed Jan 09, 2019 10:15 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760350
Re: Post All Chemistry Jokes Here
You must be full of copper and tellurium because you're CuTe!
- Fri Dec 07, 2018 3:00 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760350
Re: Post All Chemistry Jokes Here
The best thing about learning equilibrium is that nothing changes.
- Fri Dec 07, 2018 3:00 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760350
Re: Post All Chemistry Jokes Here
Don't tell jokes to noble gases you'll get no reaction.
- Thu Nov 08, 2018 11:53 am
- Forum: Lewis Structures
- Topic: Octet rule question
- Replies: 6
- Views: 751
Re: Octet rule question
elements in the 3rd period and onwards are able to take advantage of their empty d orbital and expand their octet past the 8 electrons that come with the p and s orbitals.
- Thu Nov 08, 2018 11:43 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760350
Re: Post All Chemistry Jokes Here
all the good chemistry jokes Argon, i think we should take the bad ones and Barium.
- Thu Nov 08, 2018 11:41 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760350
- Thu Nov 08, 2018 11:40 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2760350
Re: Post All Chemistry Jokes Here
what is the chemical formula for a banana?
BaNa2
BaNa2
- Thu Nov 08, 2018 11:37 am
- Forum: Bond Lengths & Energies
- Topic: bond lengths and strengths
- Replies: 9
- Views: 885
Re: bond lengths and strengths
the longer the bong the weaker it is, this is because if the bond length is longer it is easier to break
- Thu Nov 08, 2018 11:36 am
- Forum: Lewis Structures
- Topic: Formal charge question
- Replies: 9
- Views: 861
Re: Formal charge question
if you have accounted for all the electrons and checked for everything else (like stated above,) yes, formal charge is a great way double check that your structure is in the most stable form.
- Thu Nov 08, 2018 11:34 am
- Forum: Properties of Light
- Topic: Exam 2 Question 4A
- Replies: 6
- Views: 816
Re: Exam 2 Question 4A
e=hv, like stated above should have been used, but it was also necessary to convert the units from kJ to J which could result in error as well.
- Thu Nov 08, 2018 11:31 am
- Forum: Octet Exceptions
- Topic: Copper
- Replies: 10
- Views: 899
Re: Copper
^^ the rule applies for copper and chromium and all elements under them in the 9th and 6th groups (however lavelle said in class we won't be going past the 4th period so we don't need to worry about any elements other than copper and chromium)
- Thu Nov 08, 2018 11:29 am
- Forum: Bond Lengths & Energies
- Topic: MIDTERM Bond Length Question
- Replies: 15
- Views: 1493
Re: MIDTERM Bond Length Question
since there was only the two bonds, the length would be the average of their individual lengths, so the average of 140 and 120, resulting in 130
- Thu Nov 08, 2018 11:28 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 11
- Views: 1196
Re: Formal Charge
formal charge is very relative and dependent on the amount of valance electrons an element has in the periodic table and how many it is given in the lewis structure
- Thu Nov 08, 2018 11:26 am
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 3
- Views: 351
Re: Resonance Structures
the location of a bond in a structure can be interchanged, there is a resonance structure.
in this example, the double bond can be written on either side and therefore there is resonance
in this example, the double bond can be written on either side and therefore there is resonance
- Thu Nov 08, 2018 11:22 am
- Forum: Lewis Structures
- Topic: Formal charges
- Replies: 15
- Views: 1176
Re: Formal charges
formal charges can be used to help determine the most stable lewis structure, however you dont need to explicitly state them unless the questions says so
- Thu Nov 08, 2018 11:18 am
- Forum: Bond Lengths & Energies
- Topic: Bond Length and Bond Strength
- Replies: 5
- Views: 769
Re: Bond Length and Bond Strength
thats correct! and the shorter the bond the stronger it is
- Thu Nov 08, 2018 11:18 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge & Stable lewis structures
- Replies: 6
- Views: 778
Re: Formal Charge & Stable lewis structures
the goal is to make the formal charge for each element 0 or as close to 0 as possible. if after calculating the formal charges of each element in the compound there are no elements with 0 formal charges, there is likely a better structure that can be shown.
- Thu Nov 08, 2018 11:15 am
- Forum: Lewis Structures
- Topic: Expanded octet
- Replies: 4
- Views: 389
Re: Expanded octet
electrons in the 3rd period and on can take advantage of their empty d orbital and use it to hold electrons and make themselves more stable by reducing their formal charge (resulting in going over the 8 that gets held by the p+s orbitals)
- Sun Oct 28, 2018 5:56 pm
- Forum: Ionic & Covalent Bonds
- Topic: Trend of Ionic Radii
- Replies: 5
- Views: 494
Re: Trend of Ionic Radii
ionic radius, atomic radius, and covalent radius all follow the same trends, increases down a group and decreases across a period, being greatest in the bottom right corner of the periodic table
- Sun Oct 28, 2018 5:52 pm
- Forum: Ionic & Covalent Bonds
- Topic: the Octet rule
- Replies: 21
- Views: 3904
Re: the Octet rule
all elements follow the octet rule except hydrogen, helium, lithium, and beryllium which have a max of 2 valance electrons
- Sun Oct 28, 2018 5:49 pm
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 8
- Views: 650
Re: Lewis Structures
the number of electrons is equivalent to the amount of valance electrons the element has
- Mon Oct 22, 2018 3:18 pm
- Forum: *Particle in a Box
- Topic: Test 2
- Replies: 9
- Views: 1283
Re: Test 2
reviewing whats on the quantum world outline on his website should help!
- Mon Oct 22, 2018 3:16 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 37511
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
thank you these are so helpful!
- Mon Oct 22, 2018 3:12 pm
- Forum: Properties of Light
- Topic: kg or g [ENDORSED]
- Replies: 11
- Views: 1548
Re: kg or g [ENDORSED]
everything uses kg, molar mass is given in g per mole however for simplicity purposes and to make it easier to write out.
- Mon Oct 22, 2018 3:11 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: What is the equation used for?
- Replies: 9
- Views: 832
Re: What is the equation used for?
the equation is used to calculate the range in momentum or position of the electron as both cannot be calculated accurately at the same time. due to the way we carry out the experiment to calculate for position and momentum, we can not be certain of the values of one.
- Sat Oct 13, 2018 2:50 pm
- Forum: DeBroglie Equation
- Topic: De Broglie Equation Dividing J*s by kg*m/s
- Replies: 2
- Views: 995
Re: De Broglie Equation Dividing J*s by kg*m/s
1 J= 1 kg.m^2.s^(-2) the units in the de broglie equation are: (J.s)/(kg.m/s) this becomes: [(1 kg.m^2.s^(-2))(s)]/(kg.m/s) the kgs on both sides cancel out there is a s^(-2) and s on top, and a s on the bottom, these cancel out as well the m^2 on top cancels out with one m on the bottom to end with...
- Sat Oct 13, 2018 2:46 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Wavelike properties
- Replies: 7
- Views: 381
Re: Wavelike properties
wavelengths under 10^-15 or 10^-18 are so small that their wavelengths cannot be detected and therefore are said to have no wavelike properties
- Sat Oct 13, 2018 2:45 pm
- Forum: DeBroglie Equation
- Topic: Wavelike Properties
- Replies: 2
- Views: 137
Re: Wavelike Properties
everyday objects and objects that can be seen with the human eye won't have detectable wavelike properties
- Sun Oct 07, 2018 8:38 pm
- Forum: Properties of Light
- Topic: Chapter 1 Homework
- Replies: 6
- Views: 556
Re: Chapter 1 Homework
7 problems relevant to the material are due every week in your discussion section
- Sun Oct 07, 2018 8:37 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Procedure
- Replies: 7
- Views: 722
Re: Balancing Procedure
adding an O atom would change the composition of the molecule and therefore change the substance
- Sun Oct 07, 2018 8:36 pm
- Forum: Limiting Reactant Calculations
- Topic: Theoretical Yield
- Replies: 7
- Views: 891
Re: Theoretical Yield
due to side reactions and impurities the actual yield will often be less than the theoretical yield
- Thu Oct 04, 2018 12:54 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical Formula
- Replies: 6
- Views: 555
Re: Empirical Formula
technically you can use any mass you choose however 100g is almost always used as it reduces the amount of calculations needed and makes it simpler
- Thu Oct 04, 2018 12:49 pm
- Forum: Empirical & Molecular Formulas
- Topic: Definition of Empirical Formula
- Replies: 8
- Views: 593
Re: Definition of Empirical Formula
the empirical formula simplifies the ratio of the atoms in a formula, the molecular formula shows the actual number. as a result, the empirical formula of multiple molecules could be the same while the molecular formulas cannot
- Thu Oct 04, 2018 12:44 pm
- Forum: Significant Figures
- Topic: Sig Fig's in Problem E.21.d
- Replies: 3
- Views: 412
Re: Sig Fig's in Problem E.21.d
I'm assuming they are using the molar mass of H as its shown in the front cover of the book, in which case it would be 1.0079 g.mol-1 which has 5 sigfigs