Search found 69 matches
- Sat Mar 16, 2019 8:18 pm
- Forum: Phase Changes & Related Calculations
- Topic: heat capacity of an object
- Replies: 3
- Views: 596
Re: heat capacity of an object
yah specific heat capacity is joules kelvin, there doesnt exist a grams in it since it depends on how much of the thing is
- Sat Mar 16, 2019 8:14 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: concentration cell vs galvanic cell
- Replies: 3
- Views: 1527
Re: concentration cell vs galvanic cell
Does a concentration cell always have to have a porous disk?
- Sat Mar 16, 2019 8:12 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: standard cell potentials
- Replies: 5
- Views: 400
Re: standard cell potentials
I believe when a galvanic cell is negative then it will favor the reactants rather than the products
- Sat Mar 16, 2019 8:01 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Collision model
- Replies: 3
- Views: 320
Re: Collision model
The collision model basically states that molecules must collide with a great enough energy to break bonds. The activated complex is an intermediate states when reactants convert into products
- Sat Mar 16, 2019 7:58 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell potential and Gibbs Free energy
- Replies: 2
- Views: 496
Re: Cell potential and Gibbs Free energy
n is the number of electrons used within the redox reaction
- Sat Mar 16, 2019 7:58 pm
- Forum: First Order Reactions
- Topic: Half-Life and Rate Constant
- Replies: 1
- Views: 623
Re: Half-Life and Rate Constant
The first order half life equation is .693 over k so the greater k value means smaller or shorter half life time
- Sat Mar 16, 2019 7:56 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Catalyst in rate law?
- Replies: 6
- Views: 8012
Re: Catalyst in rate law?
Catalyst can be present within the rate law
- Sat Mar 16, 2019 10:48 am
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7390
Re: LYNDON'S PORK RAMEN REVIEW
Thank you so much for everything you have done for us lyndon!
- Fri Mar 15, 2019 8:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Review Worksheet (Sunday 3-4)
- Replies: 2
- Views: 438
Re: Review Worksheet (Sunday 3-4)
Should problem 1a be to the negative 6th power instead of negative 5th power?
- Thu Mar 14, 2019 1:32 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalysts
- Replies: 6
- Views: 561
Re: Catalysts
In lecture, Lavell mentioned that catalyst are present at the beginning of the equation as they are needed for the reaction to take place. Whereas an intermediate is produced as a product but then used up as an reactant.
- Thu Mar 14, 2019 11:31 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Reducing power
- Replies: 4
- Views: 443
Re: Reducing power
So in a galvanic cell, whichever one is more positive, that means its more likely to be reduced and thus gains electrons (having e on the reactant side), and the more negative one is likely to be oxidized, and thus lose electrons (having e on the product side)?
- Thu Mar 14, 2019 10:58 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Week 9 Worksheet (2E,I,K)
- Replies: 13
- Views: 5259
Re: Week 9 Worksheet (2E,I,K)
Thank you so much!
- Wed Feb 27, 2019 9:45 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Value of n
- Replies: 7
- Views: 923
Re: Value of n
Sometimes there are cases where you simplify the balanced redox reaction, would n be the number of moles before simplification or would it be the number of moles after simplification?
- Wed Feb 27, 2019 9:35 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: determining n
- Replies: 4
- Views: 494
Re: determining n
would there be no units for n since its just the # of moles then?
- Wed Feb 20, 2019 7:46 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Potential Difference
- Replies: 2
- Views: 276
Re: Potential Difference
Potential is basically the cell potential in which how much voltage exists between the cathode and the anode. Thats why when there is "very little current flow" as said in the lecture (meaning before most of the reaction has taken place), the potential is the greatest.
- Wed Feb 20, 2019 7:41 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing agents and oxidizing agents
- Replies: 6
- Views: 683
Re: Reducing agents and oxidizing agents
A simple acronym that helps to remember which is OIL RIG
OIL= Oxidation Is Loss (of electrons)
RIG= Reduction Is Gain (of electrons)
OIL= Oxidation Is Loss (of electrons)
RIG= Reduction Is Gain (of electrons)
- Wed Feb 20, 2019 7:39 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells
- Replies: 7
- Views: 632
Re: Galvanic Cells
It's basically just the drawing on the board that Lavelle had where a spontaneous redox reaction (the cathode and the anode) converts chemical energy into electrical energy through the transfers of electrons
- Sun Feb 10, 2019 10:33 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Midterm [ENDORSED]
- Replies: 49
- Views: 4720
Re: Midterm [ENDORSED]
The notes area also extremely important. If you can, try to memorize even the small details that might seem arbitrary. I remember in 14a Lavelle put some questions on the test that were briefly mentioned in class.
- Sun Feb 10, 2019 10:30 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
- Replies: 49
- Views: 11478
Re: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
Yah for number six, im confused as well. Internal energy is dependent on temperature and the work function for a reversible reaction has temperature for one of the unknown variables. Is there a way around this?
- Sun Feb 10, 2019 10:24 pm
- Forum: Calculating Work of Expansion
- Topic: Week 5 Discussion Notes&worksheet (2E,I,K)
- Replies: 3
- Views: 687
Re: Week 5 Discussion Notes&worksheet (2E,I,K)
Thank you so much!
- Sun Feb 03, 2019 7:18 pm
- Forum: Phase Changes & Related Calculations
- Topic: Work
- Replies: 2
- Views: 288
Re: Work
There are also other work equations such as work=-P*delta V where work is done by the system causing energy to decrease
- Sun Feb 03, 2019 5:50 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Predicting Spontaneity
- Replies: 4
- Views: 1415
Re: Predicting Spontaneity
There are charts that you can search up in which it gives you if T is a high number when delta H is positive and so is delta s then it will be spontaneous and so on. It can somewhat help you conceptually. However, essentially if you just plug in big or small values for the equation you can get a gag...
- Sun Feb 03, 2019 5:34 pm
- Forum: Calculating Work of Expansion
- Topic: R constant
- Replies: 3
- Views: 290
Re: R constant
The R constant can be determined with which equation you have to use. For example in the pV=nrt function it will be 8.314*10^7 while the rydberg formula for finding energy states would be 1.097*10^7.
- Sun Feb 03, 2019 5:27 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: constant pressure/volume vs specific/molar heat capacities
- Replies: 4
- Views: 385
Re: constant pressure/volume vs specific/molar heat capacities
the information given is always the biggest clue, what units are and what fits into the equation will help you solve for what you need to find.
- Tue Jan 29, 2019 10:42 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat Capacity
- Replies: 5
- Views: 462
Re: Heat Capacity
When they ask you the question the information should be enough for you to determine whether or not to calculate specific, molar, or just plain heat capacity
- Tue Jan 29, 2019 10:31 am
- Forum: Phase Changes & Related Calculations
- Topic: Different enthalpy calculation methods
- Replies: 4
- Views: 396
Re: Different enthalpy calculation methods
The information present in the question given will allow you to determine which method to use
- Mon Jan 28, 2019 10:24 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 3
- Views: 328
Re: Hess's Law
you will be given the enthalpy with the initial rxns but just keep in mind you will also need to use that to find the final reaction enthalpy.
- Mon Jan 28, 2019 10:23 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam
- Replies: 11
- Views: 955
Re: Steam
steam does cool down but it's still immediately displacing the energy that was necessary to change water into steam in the heating curve.
- Mon Jan 28, 2019 10:20 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: 483
Re: Hess's Law (Method 1)
they're almost similar to math equations. Whatever you do to one you have to do to another, so if the rxn in the second equation is multiplied by two or divided by two you much also do the same to the enthalpy. It will be more convenient to keep track of if you add them together
- Wed Jan 23, 2019 2:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Does [H3O+][OH-] always equal 10^-14?
- Replies: 9
- Views: 1164
Re: Does [H3O+][OH-] always equal 10^-14?
even if kw is not equal to 1*10^-14, [H3O+][OH-] is still equal to kw and to find concentration, you just sqaureroot the kw
- Sat Jan 19, 2019 9:35 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ignoring solids
- Replies: 6
- Views: 733
Re: ignoring solids
The change in liquids such as water is so small in even in equilibrium there is large excess of it so it would cancel out in K and thus is not included. Solids also don’t affect the constant and is left out as well
- Sat Jan 19, 2019 9:24 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure
- Replies: 4
- Views: 530
Re: Pressure
There is no change since the number of moles balance on both sides. Equilibrium would not shift either way
- Sun Jan 13, 2019 2:50 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic Reactions
- Replies: 9
- Views: 791
Re: Exothermic Reactions
in the modules he also mentioned you can tell if a reaction is exo or endo by looking at the lewis structure depending on whether or not they form or break bonds
- Sun Jan 13, 2019 2:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant Eq.
- Replies: 4
- Views: 362
Re: Equilibrium Constant Eq.
the concentrations and ratio do not change since youre using the concentration of product over reactant to find the ratio which is the equilibrium constant
- Sun Jan 13, 2019 2:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: HW 2 Due Date
- Replies: 4
- Views: 416
Re: HW 2 Due Date
yes. only homework one is due during class the rest of the homeworks are all due during your discussion section
- Thu Dec 06, 2018 10:15 pm
- Forum: Naming
- Topic: Common Names
- Replies: 1
- Views: 167
Common Names
For the final exam, would we need to know the common names of metals? Such as ferrate or ferrous for iron and cuprous for copper?
- Thu Dec 06, 2018 9:55 pm
- Forum: Naming
- Topic: Final Exam
- Replies: 9
- Views: 834
Final Exam
For the final exam, would we need to know the chemical formula for ethylenediamine or do we just need to write en?
- Thu Dec 06, 2018 2:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 20861
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Thank you so much to my favorite UA. I greatly appreciate your practice problems!
- Sun Dec 02, 2018 10:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: repulsion
- Replies: 3
- Views: 374
Re: repulsion
In bonding and vsepr models, the central atom dictates shape since its the atom that pairs with all other valence electrons. The other lone pairs are not significant enough in repulsion to affect the shape since they are essentially on the outskirts of the atom. The lone pairs on the central atom ho...
- Sun Dec 02, 2018 10:11 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: ionization of weak bases
- Replies: 1
- Views: 169
Re: ionization of weak bases
The backwards reaction causes the equation to produce reactants that are on the left side of the equation as well as products. They are not strong enough to completely dissociate
- Sun Dec 02, 2018 10:09 pm
- Forum: Bronsted Acids & Bases
- Topic: Fundamentals J.1 Bronsted Acids and Bases
- Replies: 2
- Views: 404
Re: Fundamentals J.1 Bronsted Acids and Bases
The lewis structures could also help you visualize which atoms give or receive an electron. Depending on the lone pairs and the electronegativity of the atom you can get an idea of which ones will be more likely to donate.
- Sun Dec 02, 2018 10:04 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 513955
Re: Saying Thank You to Dr. Lavelle
Dear Dr. Lavelle,
Thank you for your explanations in chem that make the material more understandable. I never thought it would be a subject that I would understand and your jokes are pretty funny! I look forward to next quarter with you in chem 14b :) Happy holidays
Thank you for your explanations in chem that make the material more understandable. I never thought it would be a subject that I would understand and your jokes are pretty funny! I look forward to next quarter with you in chem 14b :) Happy holidays
- Mon Nov 26, 2018 7:47 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: HW 6th edition 4.25a
- Replies: 1
- Views: 249
Re: HW 6th edition 4.25a
will test three specify whether molecular structures will be cis or trans?
- Mon Nov 26, 2018 7:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR shape
- Replies: 4
- Views: 454
Re: VSEPR shape
The lone pairs also play a part in determining molecular shape due to their repulsion. For trigonal pyramidal there is only one lone pair while t shaped has two
- Mon Nov 26, 2018 7:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Bond Angles
- Replies: 6
- Views: 16045
Re: Seesaw Bond Angles
would we also need to include the 180 degree angle when they ask for the bond angles?
- Mon Nov 19, 2018 5:41 pm
- Forum: Hybridization
- Topic: Ethene Hybridization
- Replies: 4
- Views: 398
Re: Ethene Hybridization
im confused too, if its occupying three orbitals then wouldnt that make it sp3 instead of sp2 and have another electron in an unhybridized orbital?
- Mon Nov 19, 2018 5:26 pm
- Forum: Sigma & Pi Bonds
- Topic: Double Bonds and Triple Bonds
- Replies: 2
- Views: 428
Re: Double Bonds and Triple Bonds
the sigma bond is the first bond between the two elements and thus any bond created after that can only pair side by side, creating the different pi bonds. The triple bond has the same concept where the electrons pair side by side.
- Mon Nov 19, 2018 4:55 pm
- Forum: Hybridization
- Topic: Sigma and Pi Bonds [ENDORSED]
- Replies: 12
- Views: 1037
Re: Sigma and Pi Bonds [ENDORSED]
pi bonds are bonded side by side different than sigma bonds, because of the physical structure, rotating the molecule along the sigma bond would cause the pi bond to snap.
- Mon Nov 19, 2018 4:47 pm
- Forum: Hybridization
- Topic: Labeling Compounds
- Replies: 4
- Views: 324
Re: Labeling Compounds
you can think of it as kind of the "_" that are drawn for the electron orbitals. There are only three p orbitals and thats why it does not go higher than sp3
- Mon Nov 19, 2018 3:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs and bonding
- Replies: 4
- Views: 404
Re: Lone pairs and bonding
Because lone pairs are unbound electrons, they have a much larger electron cloud and repulsion energy, thus push down the other electron densities such as the bond angles. In class lavelle showed us that by replacing a molecule (taking it off the stick), the area becomes much more occupied and resul...
- Mon Nov 19, 2018 3:43 pm
- Forum: Sigma & Pi Bonds
- Topic: Rotating Pi bonds
- Replies: 3
- Views: 360
Re: Rotating Pi bonds
Pi bonds break if they are rotated. This is due to their rigidness and the way that they are bonded side by side, different than sigma bonds.
- Sun Nov 11, 2018 11:05 pm
- Forum: Properties of Light
- Topic: Test 3
- Replies: 24
- Views: 2112
Re: Test 3
Dr. Lavelle should tell us in class soon but so far it's going to be everything after the midterm like the lewis structures, bond energy, types of bonds and such
- Sun Nov 11, 2018 10:54 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge on central atom
- Replies: 5
- Views: 1060
Re: Formal charge on central atom
additionally, the central atom is alway the least electronegative so the surrounding atoms bonded would much rather have the more negative charge
- Sun Nov 11, 2018 10:51 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3009232
Re: Post All Chemistry Jokes Here
Chemistry is Fluorine, Uranium, Nitrogen
- Sun Nov 04, 2018 2:34 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal planes
- Replies: 6
- Views: 1285
Re: Nodal planes
would we need to know the difference between angular and radial planes on the midterm?
- Sat Nov 03, 2018 9:39 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 17220
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
hello! does anyone know how soon the solutions sheet will be up?
- Sun Oct 28, 2018 11:46 pm
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 13
- Views: 991
Re: Lewis Structures
Dr. Lavelle also mentioned Li and Be in addition to H and He as never fulfilling the octet rule
- Sun Oct 28, 2018 11:45 pm
- Forum: Lewis Structures
- Topic: Lewis Structures with Polyatomic Species
- Replies: 2
- Views: 517
Re: Lewis Structures with Polyatomic Species
The four H atoms are on the outside of N and since N has five valence electrons, there will be a bond connecting the two NH4 structures with the SO4
- Sun Oct 28, 2018 11:39 pm
- Forum: Ionic & Covalent Bonds
- Topic: Octet Rule
- Replies: 7
- Views: 649
Re: Octet Rule
The exceptions are H, He, Li, and Be since they will always be the elements giving their electrons instead of receiving them
- Sun Oct 28, 2018 11:37 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3009232
Re: Post All Chemistry Jokes Here
If avagrado calls, tell him to leave his number ;)
- Sun Oct 21, 2018 9:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 3
- Views: 379
Re: Nodal Planes
Since the nodal plane is a plane, don't the electrons cross over it at one point to the orbital on the other side? I understand that there's zero possibility but in cases of the p orbital where there's two orbital won't the electron have to circulate both?
- Sun Oct 21, 2018 9:49 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3009232
Re: Post All Chemistry Jokes Here
Chemistry? More like Chemystery
- Sun Oct 21, 2018 9:44 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 383030
Re: Advice from a Medical Student [ENDORSED]
Thank you so much for all your advice! This will definitely help us all out years from now :)
- Sun Oct 14, 2018 5:59 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3009232
Re: Post All Chemistry Jokes Here
Take all your lame chemistry jokes, and Barium.
- Sun Oct 14, 2018 5:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test #2
- Replies: 3
- Views: 345
Re: Test #2
Test 2 will begin Tuesday Oct 23rd in our discussion, similar to how Test 1 was. So it would be the 10/22-10/26, depending on what day your discussion is. @danny
- Sun Oct 14, 2018 5:52 pm
- Forum: Properties of Electrons
- Topic: Photoelectric Experiment
- Replies: 9
- Views: 512
Re: Photoelectric Experiment
I understand the difference between intensity and frequency but in an actual experiment, how would you physically raise the frequency of the of the light source?
- Sun Oct 07, 2018 3:53 pm
- Forum: Significant Figures
- Topic: Sig Figs & Molar Mass
- Replies: 4
- Views: 577
Re: Sig Figs & Molar Mass
I'm pretty sure you're suppose to use the least amount of sig figs found in the problem to avoid any "false accuracy". If there isn't any numbers given in the problem then a good amount would be three sig figs.
- Sun Oct 07, 2018 3:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Registering/Creating Your Chemistry Community Account
- Replies: 40
- Views: 100364
Re: Registering/Creating Your Chemistry Community Account
Is there a system where they can automatically track if we had posted or not?
- Sun Oct 07, 2018 3:42 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3009232
Re: Post All Chemistry Jokes Here
I tried to tell a chemistry joke but it got no reaction