Search found 46 matches
- Sun Mar 17, 2019 10:11 am
- Forum: Second Order Reactions
- Topic: Plotting second order reactions
- Replies: 3
- Views: 655
Re: Plotting second order reactions
In order to get a straight line plot for a second order rxn you must use the integrated rate law and plot 1/[A] vs. time. The slope will be a positive K value
- Sun Mar 17, 2019 10:09 am
- Forum: Zero Order Reactions
- Topic: Zero order reaction
- Replies: 8
- Views: 1033
Re: Zero order reaction
The graph of a zero order reaction will be [A] vs. time and will have a slope of -K
- Sat Mar 16, 2019 6:04 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Intermediates in Rate Law
- Replies: 4
- Views: 464
Intermediates in Rate Law
Do you include intermediates in the rate laws for elementary steps in reaction mechanisms?
- Sat Mar 16, 2019 11:54 am
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7642
Re: LYNDON'S PORK RAMEN REVIEW
Will the answers be posted after your review session? Thank you for your help!
- Sat Mar 16, 2019 10:36 am
- Forum: General Rate Laws
- Topic: Phase of Reactants in Rate Law
- Replies: 3
- Views: 719
Phase of Reactants in Rate Law
Are there any phases of reactants that we exclude when writing rate laws? When we write K, for example, we exclude solids. Does this apply for rate laws as well?
- Fri Mar 15, 2019 9:57 pm
- Forum: Van't Hoff Equation
- Topic: Test #2
- Replies: 5
- Views: 756
Re: Test #2
for my K2 value I got 2.78*10^-14
On my test I took the negative log of this value but got the answer wrong, is that the wrong approach?
On my test I took the negative log of this value but got the answer wrong, is that the wrong approach?
- Fri Mar 15, 2019 9:53 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Equation sheet
- Replies: 4
- Views: 522
Equation sheet
Will the Nernst equation be on our equation sheet?
- Fri Mar 15, 2019 9:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Exam Practice Problem
- Replies: 3
- Views: 619
Re: Final Exam Practice Problem
Are these questions taken from past final exams?
- Tue Mar 12, 2019 11:29 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong Acid/Base Concentration vs. Weak Acid/Base Concentration
- Replies: 2
- Views: 324
Strong Acid/Base Concentration vs. Weak Acid/Base Concentration
Can someone explain the difference in calculating concentrations for a strong acid or base vs. calculating concentration for a weak acid or base?
- Mon Mar 11, 2019 9:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constants and Solubility
- Replies: 2
- Views: 341
Equilibrium Constants and Solubility
How do you determine solubility from the equilibrium constant?
- Mon Mar 11, 2019 7:23 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law as an Approximation
- Replies: 10
- Views: 1001
Ideal Gas Law as an Approximation
In the outline Dr. Lavelle posted, he says we need to be able to identify reactions where the ideal gas law can be used as an approximation.
What exactly does this mean?
What exactly does this mean?
- Wed Feb 27, 2019 6:25 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: #14.13 Part D (Sixth Edition)
- Replies: 1
- Views: 232
Re: #14.13 Part D (Sixth Edition)
I'm stuck on the same problem, I think it might have to do with adding the two half reactions together at the end and having the final equation be balanced, but I'm not sure. If someone could explain this that would be great!
- Wed Feb 27, 2019 5:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Pt (s) [ENDORSED]
- Replies: 8
- Views: 972
Re: Pt (s) [ENDORSED]
In the homework problem 6L5 part b in the 7th edition, one of the cell diagrams is Pt(s)|I^-(aq)|I2(s)||Ce^4+(aq), Ce^3+(aq)|Pt(s)
I don't really understand why the Pt is included here, can someone explain?
I don't really understand why the Pt is included here, can someone explain?
- Tue Feb 05, 2019 7:16 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Reversible Processes
- Replies: 2
- Views: 321
Reversible Processes
Can someone explain what a reversible process is?
- Tue Feb 05, 2019 7:10 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Ideal Gas
- Replies: 3
- Views: 418
Ideal Gas
What exactly is an ideal gas?
- Wed Jan 30, 2019 8:29 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 7th edition 4C.3
- Replies: 1
- Views: 257
7th edition 4C.3
This question, you have to use the formulas: qp=nCpDeltaT and qv=nCvDeltaT, but in the solution book they substitute Cp for (5/2R) and Cv for (3/2R). Can someone explain these substitutions?
- Tue Jan 29, 2019 7:28 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity vs. enthalpy
- Replies: 4
- Views: 671
Re: Heat capacity vs. enthalpy
If I understand correctly, I believe that heat capacity is sort of a sub-category of enthalpy. Enthalpy is the study of heat released or absorbed in chemical reactions and physical changes, where heat capacity is simply the amount of heat required to raise the temperature of an object by 1 degree C.
- Mon Jan 28, 2019 1:33 pm
- Forum: Phase Changes & Related Calculations
- Topic: SI Unit
- Replies: 2
- Views: 304
Re: SI Unit
kilojoules
- Mon Jan 28, 2019 1:31 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy and state property
- Replies: 2
- Views: 301
Re: Enthalpy and state property
Enthalpy is a state property because the value of enthalpy is determined by its current state, not on the pathway taken to obtain that value. To use Dr. Lavelle's example from class, if someone went on a hike, the distance they travelled would not be a state property, however, their altitude change ...
- Mon Jan 28, 2019 1:27 pm
- Forum: Phase Changes & Related Calculations
- Topic: Delta Hº versus delta H
- Replies: 7
- Views: 7562
Re: Delta Hº versus delta H
deltaH^0 refers to the standard reaction enthalpy (the rxn enthalpy when all R and P are in their standard state). DeltaH is the general symbol for the amount of heat absorbed or released. There is also deltaHf^0 which refers to the Standard Enthalpy of Formation (the standard rxn enthalpy for the f...
- Mon Jan 28, 2019 1:16 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law (Method 1)
- Replies: 4
- Views: 514
Hess's Law (Method 1)
In Method 1, why is it necessary to add the rxns to get the net rxn? Why would you not simply just add together the two deltaHs?
- Mon Jan 28, 2019 1:13 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Enthalpy Formation of an element
- Replies: 4
- Views: 466
Standard Enthalpy Formation of an element
Why is it that the standard enthalpy formation of an element in its most standard form is zero?
- Mon Jan 28, 2019 1:08 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Rxn Enthalpies for liquids and solids
- Replies: 2
- Views: 325
Standard Rxn Enthalpies for liquids and solids
In the notes, Dr. Lavelle wrote "for a pure liquid or solid it [the standard rxn enthalpy] is the pure L or S"
Can someone explain what this means?
Can someone explain what this means?
- Mon Jan 28, 2019 12:55 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy vs. Heat as a state property
- Replies: 1
- Views: 200
Enthalpy vs. Heat as a state property
If q=deltaH, then why is it that enthalpy is a state property but heat is pathway dependent?
- Mon Jan 28, 2019 12:52 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Energy vs. Enthalpy
- Replies: 2
- Views: 271
Energy vs. Enthalpy
Is there a difference between the enthalpy of a reaction and the energy required for the same reaction to take place?
- Wed Jan 16, 2019 10:31 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in Pressure, 5J.5
- Replies: 1
- Views: 194
Change in Pressure, 5J.5
Can anyone explain the reasoning behind the textbook problem 5J. 5 (7th edition)? I understand why in part d there would be no change, but for a,b,c, and e I'm confused as to how you would know reactants would be favored with an overall increase in pressure.
- Mon Dec 03, 2018 12:33 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: what is a ligand?
- Replies: 8
- Views: 886
Re: what is a ligand?
Just for clarification, a ligand must be able to donate electrons in order to form a coordinate covalent bond with the central atom, correct?
- Mon Dec 03, 2018 12:30 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligand names
- Replies: 7
- Views: 834
Re: Ligand names
Dr. Lavelle mentioned in class that knowing the ligand names is useful, and that we should go to the textbook for common ligand names--however, I'm not sure if this is a requirement for the final.
- Mon Dec 03, 2018 12:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelates
- Replies: 4
- Views: 483
Re: Chelates
How are you able to tell if a molecule is a chelating molecule?
- Mon Dec 03, 2018 12:24 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: cis and trans
- Replies: 1
- Views: 264
cis and trans
If we are only given the formula for a molecule, how are we supposed to distinguish whether it is a cis or trans molecule?
- Mon Dec 03, 2018 12:18 pm
- Forum: Naming
- Topic: Knowing oxidation states
- Replies: 11
- Views: 967
Re: Knowing oxidation states
Ruiting Jia 4D wrote:Becky Belisle 1F wrote:I think it's useful to memorize the oxidation states of the common ligands.
Which are the common ligands that we would need to memorize for?
Is there a certain place in the textbook that is good for studying this?
- Mon Nov 26, 2018 7:41 pm
- Forum: Resonance Structures
- Topic: Bond Lengths
- Replies: 3
- Views: 572
Bond Lengths
If you have, for example, SO2, SO3, and SO3^2-, each molecule has a lewis structure with single bonds and one double bond.
If all of them have resonance, how would you determine which bond lengths are longer/shorter in comparison to one another? Are they all the same length?
If all of them have resonance, how would you determine which bond lengths are longer/shorter in comparison to one another? Are they all the same length?
- Sun Nov 25, 2018 4:23 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Energy of Interactions
- Replies: 4
- Views: 412
Energy of Interactions
In Dr. Lavelle's lecture notes for interactions between ions and molecules, he wrote:
1. Ion-Ion : Na+Cl- -250 kJ/mol
What does the -250 kJ/mol represent? How do you find this number if it is not given/what use does it have?
1. Ion-Ion : Na+Cl- -250 kJ/mol
What does the -250 kJ/mol represent? How do you find this number if it is not given/what use does it have?
- Sat Nov 24, 2018 8:19 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3
- Replies: 10
- Views: 994
Re: Test 3
Does anyone remember what the website was that Dr. Lavelle mentioned in class that has learning modules similar to the ones we had for the first units? I could be wrong but I remember him making a comment about more learning modules.
- Mon Nov 05, 2018 12:39 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39493
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
On the midterm review worksheet, could someone explain how to draw the lewis structure for XeO2F2?
- Mon Nov 05, 2018 11:05 am
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 21527
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Could someone please explain the mathematics behind 13E to me?
- Mon Nov 05, 2018 10:46 am
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 21527
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Could someone explain why for 13D (I looked this up on the internet) the atoms have different electron configurations? I know that the electron configurations are: Neutral SC Atom: 1s2 2s2 2p6 3s2 3p6 3d1 4s2 SC2+ Ion: 1s2 2s2 2p6 3s2 3p6 3d1 Neutral K atom: 1s2 2s2 2p6 3s2 3p6 4s1 But could someon...
- Mon Nov 05, 2018 10:46 am
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 21527
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Could someone explain why for 13D (I looked this up on the internet) the atoms have different electron configurations? I know that the electron configurations are: Neutral SC Atom: 1s2 2s2 2p6 3s2 3p6 3d1 4s2 SC2+ Ion: 1s2 2s2 2p6 3s2 3p6 3d1 Neutral K atom: 1s2 2s2 2p6 3s2 3p6 4s1 But could someon...
- Mon Nov 05, 2018 9:47 am
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 21527
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Can someone please explain 10b to me? I don't understand why they wouldn't all be equal
- Sat Nov 03, 2018 6:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 21527
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
For #6, how are you supposed to convert the molar mass of GarBreadium to kg in order to use the de broglie equation?
- Sun Oct 14, 2018 12:32 pm
- Forum: Photoelectric Effect
- Topic: Threshold Energy and Energy Levels
- Replies: 1
- Views: 152
Threshold Energy and Energy Levels
Just a clarification question:
Each metal has their own unique threshold energy, correct?
Also, does this mean that each metal has their own unique energy levels that their electrons can move between?
Each metal has their own unique threshold energy, correct?
Also, does this mean that each metal has their own unique energy levels that their electrons can move between?
- Sun Oct 14, 2018 12:24 pm
- Forum: Properties of Light
- Topic: Photons of Light [ENDORSED]
- Replies: 1
- Views: 187
Photons of Light [ENDORSED]
I understand that a photon of light is like a "packet" of energy, but is there any sort of numeric value to a photon?
- Sun Oct 14, 2018 12:19 pm
- Forum: Photoelectric Effect
- Topic: Electrons Lost
- Replies: 3
- Views: 371
Electrons Lost
In the photoelectric effect, does the electron that is released come from the metal that the EM radiation is shining on?
- Sun Oct 07, 2018 4:14 pm
- Forum: Limiting Reactant Calculations
- Topic: Calculating Molar Mass in Limiting Reactant Problem
- Replies: 3
- Views: 446
Calculating Molar Mass in Limiting Reactant Problem
In Prof. Lavelle's lecture notes on how to find limiting reactants, he said in step 3 to calculate the molar mass of each reactant and product. However in the example he gave us he only calculated the molar mass for one of the products and not the other. Why is this?
- Sun Oct 07, 2018 3:49 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39493
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Would you say that these worksheet problems are somewhat similar to problems we will see on the test? Or do you think doing problems out of the textbook are more helpful in preparing for the test?
- Sun Oct 07, 2018 3:38 pm
- Forum: Empirical & Molecular Formulas
- Topic: When to double moles
- Replies: 13
- Views: 1073
Re: When to double moles
Yes I believe so because if you were to multiply 1.1 by 9 to get closer to a whole number you would still be .1 away from the nearest whole number.