Search found 109 matches
- Fri Mar 13, 2020 10:07 am
- Forum: Administrative Questions and Class Announcements
- Topic: Final Topics
- Replies: 10
- Views: 819
Re: Final Topics
I am just going to put together a comprehensive study guide with a ton of example problems from outlines 1-6.
- Thu Mar 12, 2020 3:11 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Format because I posted in 14A by accident
- Replies: 8
- Views: 566
Re: Format because I posted in 14A by accident
My chem 14BL class made the final a gradescope exam so we have to print it out, complete it, and then turn it into gradescope within the open and close date of the test. I have heard a couple other chem profs are doing a similar type of thing but we will see.
- Thu Mar 12, 2020 2:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: W20, Week 10 Discussion 2F, 2I, 2L
- Replies: 10
- Views: 7418
Re: W20, Week 10 Discussion 2F, 2I, 2L
Thank you for posting this Dr. Lavelle!
- Thu Mar 12, 2020 2:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: "Open Book" Final?
- Replies: 30
- Views: 1952
Re: "Open Book" Final?
I am assuming this means any resources we have access to we can use for this final. I am not sure how this would work yet as we don't know the window we can turn in the test but we will see when Lavelle lets us know :)
- Tue Mar 10, 2020 9:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework 10
- Replies: 11
- Views: 646
Re: Homework 10
My TA sent us an email and told us to send him a picture of our HW. He also told us to make sure to put our name and section as it will be easier to grade.
- Tue Mar 10, 2020 9:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Grades
- Replies: 22
- Views: 1150
Re: Test 2 Grades
Grades are avaliable for viewing on MyUCLA. Also my TA said he would come up with a plan so we would be able to get them back before the final.
- Tue Mar 10, 2020 9:21 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Email Announcement
- Replies: 8
- Views: 673
Re: Email Announcement
Possibly take home or online final or maybe smaller rooms for the final exam to be given? My other classes have been changed to online exams or to turnitin.com assignments.
- Tue Mar 10, 2020 9:19 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class Cancellation
- Replies: 3
- Views: 394
Re: Class Cancellation
Yes, just shoot your TA an email with a picture of the homework to be safe. Mine emailed a couple hours ago telling us to do that.
- Tue Mar 10, 2020 9:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: final exam 2020
- Replies: 2
- Views: 341
final exam 2020
Hi! I was wondering if anyone has heard anything about what the Chem department might do about finals from friends taking other chem related exams. Also, if the format of the test will be different due to it possibly being take home, will the final exam review sessions (if we are able to have any) c...
- Tue Mar 10, 2020 9:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chemistry 14B Final
- Replies: 9
- Views: 691
Re: Chemistry 14B Final
well because all classes including discussion sections are not allowed possibly review sessions will be bruincast? And about the final, no idea, I hope we can still get partial credit for work though somehow haha.
- Sun Mar 08, 2020 11:36 pm
- Forum: Balancing Redox Reactions
- Topic: Cathode and Anode
- Replies: 24
- Views: 1539
Re: Cathode and Anode
This is because the Evalue at the cathode basically determines if the Ecell will be positive or negative. When the value is positive the system can do work, when the value is negative work must be done on the system. The equation is Ecell=Ecath-Eannode, so if Ecath>Eanode, the equation will have a n...
- Sun Mar 08, 2020 11:31 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Combustion of gas
- Replies: 6
- Views: 515
Re: Combustion of gas
I think most combustion reactions are spontaneous because they are exothermic, releasing heat, and usually cause an increase in gaseous substances, which have a higher value for entropy. It really depends on other determining factors, however.
- Sun Mar 08, 2020 11:29 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: non ideal gases
- Replies: 6
- Views: 615
Re: non ideal gases
yes, n is referring to the number of electrons transferred in the redox reactions involved at the anode and cathode.
- Sun Mar 08, 2020 11:29 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell Diagram
- Replies: 21
- Views: 1115
Re: Cell Diagram
Yes, if the potentials are not given you can assume the cathode is on the right and the anode is on the left.
- Sun Mar 08, 2020 11:27 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Figuring out n
- Replies: 15
- Views: 927
Re: Figuring out n
You balance the redox reactions, and the least common denominator of electrons transfered on the product and reactant side is equivilant to n.
- Fri Mar 06, 2020 2:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Excellence in Chemistry Award!
- Replies: 27
- Views: 9824
Re: Excellence in Chemistry Award!
awesome congrats :)
- Sun Mar 01, 2020 10:33 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: N value
- Replies: 7
- Views: 444
Re: N value
yes, you must balance both half-reactions to see if the electrons exchanged is the same, and if not multiply by a coefficient so they cancel out when they are added together to create the full balanced reaction. This value that cancels is your n.
- Sun Mar 01, 2020 10:30 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Test 2
- Replies: 4
- Views: 286
Re: Test 2
yes, we will most likely be given either a sheet with the cell potentials or they will be given on the problem if need be.
- Sun Mar 01, 2020 10:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 12
- Views: 636
Re: Salt Bridge
without the salt bridge, the charges would build up disabling the flow of electrons due to uneven charges between the two half cells of the voltaic cell. The salt bridge monitors the charges on each side, allowing electrons to continue to flow from the anode to the cathode without a buildup of posit...
- Sun Mar 01, 2020 10:16 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: test 2 topics
- Replies: 11
- Views: 711
Re: test 2 topics
The entirety of outline 5, which is electrochem, and the second page of outline 4. Do the HW probs on the outlines I think that is the best form of preparation :)
- Sun Mar 01, 2020 9:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L.3d homework question
- Replies: 3
- Views: 231
6L.3d homework question
Write the half reactions and balanced equation for the cell reaction.
I am not sure how to do this for part (d) which gives
Pt|O2|H+||OH-|O2|Pt
I don't understand how to get the half-reactions for either side.
I am not sure how to do this for part (d) which gives
Pt|O2|H+||OH-|O2|Pt
I don't understand how to get the half-reactions for either side.
- Sun Feb 23, 2020 10:04 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
If you're not part of the solution, you're part of the precipitate.
- Sun Feb 23, 2020 10:02 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
I keep laughing at the jokes on here cuz they are all sodium funny !!!
- Sun Feb 23, 2020 9:59 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 9
- Views: 506
Re: Test 2
It was moved to week 9. So during your discussion section, the test will be given.
- Sun Feb 23, 2020 9:56 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n
- Replies: 13
- Views: 713
Re: n
Based on your given values, then you can determine which value to use. 8.314 J·K-1·mol-1 or 0.0821 L·atm·K-1·mol-1 can be used to cancel out units and obtain a value.
- Sun Feb 23, 2020 9:51 pm
- Forum: Balancing Redox Reactions
- Topic: Hydroxide and H+
- Replies: 6
- Views: 377
Re: Hydroxide and H+
I think for neutral solutions mainly one should use h2o to make up the difference in redox reactions.
- Sun Feb 16, 2020 9:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2
- Replies: 11
- Views: 698
Re: Test 2
Test 2 will be based on material after the midterm. Since much of the midterm was acid-base and equilibria, however, I would also study some thermochemistry and thermodynamics just in case.
- Sun Feb 16, 2020 9:49 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm Curve
- Replies: 45
- Views: 2135
Re: Midterm Curve
I think he will curve the class to the median which is a B.
- Sun Feb 16, 2020 9:47 pm
- Forum: Ideal Gases
- Topic: STP
- Replies: 12
- Views: 1484
Re: STP
STP is just 273.15K and 1 atm. These values are mainly just for theoretical calculations because 0K is not feasible in everyday life.
- Sun Feb 16, 2020 9:40 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Delta S
- Replies: 8
- Views: 1365
Re: Delta S
DeltaS total= DeltaS system + DeltaS surroundings
And temperature does help determine if a reaction is spontaneous. Using the formula deltaG=deltaH - TdeltaH you can see if a reaction will be spontaneous or not depending on T.
And temperature does help determine if a reaction is spontaneous. Using the formula deltaG=deltaH - TdeltaH you can see if a reaction will be spontaneous or not depending on T.
- Sun Feb 16, 2020 9:33 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: endo/exo and temp
- Replies: 12
- Views: 1085
Re: endo/exo and temp
Treat heat as another product or reactant. When I know a reaction is exothermic I write heat on the product side, as exothermic releases heat. If I know a reaction is endothermic I write heat on the reactant side. Then treat heat as you would a product or reactant. ex. if a reaction has an increase ...
- Sun Feb 16, 2020 9:16 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Delta S
- Replies: 6
- Views: 332
Re: Delta S
entropy is equal to S. DeltaS is the change in entropy. If the reaction is reversible, the total deltaS, which is equal to the deltaS of the system + the deltaS of the surroundings, is equal to 0.
- Sun Feb 09, 2020 10:54 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A11
- Replies: 3
- Views: 234
Re: 4A11
haha omg I just wrote down 25 instead of 22.5 ok that makes sense now
- Sun Feb 09, 2020 10:51 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A11
- Replies: 3
- Views: 234
4A11
"A calorimeter was calibrated with an electric heater, which supplied 22.5 kJ of energy as heat to the calorimeter and increased the temperature of the calorimeter and its water bath from 22.45°C to 23.97°C. What is the heat capacity of the calorimeter?" I set up this problem doing qcal=Cc...
- Sun Feb 09, 2020 10:30 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A.9 Help
- Replies: 3
- Views: 178
Re: 4A.9 Help
I was having trouble with this one too. I think the Cu final should be the same as the Water final.
The setup should be:
20*0.39*(T-100) = 50.7*4.18*(T-22)
instead of 20*0.39*(100-T) = 50.7*4.18*(T-22)
The setup should be:
20*0.39*(T-100) = 50.7*4.18*(T-22)
instead of 20*0.39*(100-T) = 50.7*4.18*(T-22)
- Sun Feb 09, 2020 9:57 pm
- Forum: Phase Changes & Related Calculations
- Topic: closed vs isolated
- Replies: 10
- Views: 512
Re: closed vs isolated
a closed system can transfer energy to the surroundings but not matter. an isolated system can not transfer energy or matter to the surroundings. an example of a closed system would be an ice pack. an example of an isolated system would be a thermos.
- Sun Feb 09, 2020 9:43 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.9
- Replies: 2
- Views: 174
4A.9
"A piece of copper of mass 20.0 g at 100.0 C is placed in a vessel of negligible heat capacity but containing 50.7 g of water at 22.0 C. Calculate the final temperature of the water. Assume that no energy is lost to the surroundings." I am unsure how to calculate the final temp of the wa...
- Sun Feb 09, 2020 8:49 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.3
- Replies: 4
- Views: 168
4A.3
Can someone explain how they calculated w for part a given "the inner diameter of the pump is 3.0 cm and the pump is depressed to 20.0cm with a pressure of 2.00atm" ?
- Sun Jan 26, 2020 11:44 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pKa and pKb
- Replies: 17
- Views: 840
Re: pKa and pKb
pKa is basically the hydronium concentration while pKb is the hydroxide concentration of a solution. pKa and pKb when added together always equals 14. You can calculate pKa or pKb from having Ka(equilibrium constant for acids) or Kb (equilibrium constant for bases) and taking the negative log.
- Sun Jan 26, 2020 11:35 pm
- Forum: Ideal Gases
- Topic: R Constant
- Replies: 26
- Views: 1112
Re: R Constant
To determine which R to use view the givens you have and then you can determine which R unit would cancel out the appropriate units to get what value you desire. For most calculations, like in the VP=nRT equation, it will be 0.08206.
- Sun Jan 26, 2020 11:32 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H2O as a Gas
- Replies: 69
- Views: 6150
Re: H2O as a Gas
if h2o is a gas, you include it in the ICE table. You only don't include substances that have a set amount of space they take up like a solid or a liquid.
- Sun Jan 26, 2020 11:27 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Shifts Left or Right
- Replies: 15
- Views: 527
Re: Reaction Shifts Left or Right
Because this is an exothermic reaction, an increase in heat will shift to the left because you can basically treat heat as you would treat an increase in a product on the product side. Having an excess of a product on one side will cause the reaction to go towards the reactants side in order to main...
- Sun Jan 26, 2020 11:25 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure vs. Volume
- Replies: 6
- Views: 242
Re: Pressure vs. Volume
One trick I like to use is to look at the relationship between the variables of the PV=nRT equation. because P and V are on the same side of the equation that means they have an inverse relationship. This means an increase in one leads to a decrease in the other and vice versa.
- Sun Jan 19, 2020 11:51 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
If Avogadro calls.... tell him to leave his number ;)
- Sun Jan 19, 2020 11:48 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's principle
- Replies: 7
- Views: 384
Re: Le Chatelier's principle
Le Chatelier's principle basically is a principle that is used to help one determine what will happen in a reaction when different scenarios happen that would affect its equilibrium. By following Le Chatelier's principle one can determine the course the reaction will take to re-reach equilibrium.
- Sun Jan 19, 2020 11:44 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: temperature
- Replies: 10
- Views: 410
Re: temperature
When solving these kinds of problems, the temperature will most likely be a constant because changing the temperature during a reaction will change the equilibrium constant.
- Sun Jan 19, 2020 11:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Table
- Replies: 4
- Views: 233
Re: ICE Table
depending on whether the reaction is forward or reverse, then you can tell whether to add or subtract the change value.
- Sun Jan 19, 2020 11:34 pm
- Forum: Ideal Gases
- Topic: PV=nRT
- Replies: 13
- Views: 610
Re: PV=nRT
you can use this equation to gain information such as converting from concentration to pressure and vice versa.
- Sun Jan 12, 2020 10:35 pm
- Forum: Ideal Gases
- Topic: PV = nRT
- Replies: 16
- Views: 1820
Re: PV = nRT
P is pressure
V is volume
n is moles
R is the ideal gas constant (8.314 J / mol·K)
T is temperature in Kelvin
V is volume
n is moles
R is the ideal gas constant (8.314 J / mol·K)
T is temperature in Kelvin
- Sun Jan 12, 2020 10:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentration
- Replies: 6
- Views: 216
Re: Concentration
Are you talking about Kc? Because Kc itself doesn't have units because it is a constant. But in order to get a correct value for Kc there are units in the equation ([products]/[reactants]) that are represented by brackets, [ ]. These brackets represent molarity or mol/L.
- Sun Jan 12, 2020 10:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q
- Replies: 10
- Views: 342
Re: Q
Q helps to determine or predict the path a reaction will take after a specific time. It can be compared to K to make assumptions about the reaction at hand.
- Sun Jan 12, 2020 10:25 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kp and Kc
- Replies: 4
- Views: 234
Re: Kp and Kc
Yes, a reaction may occur with both aqueous and gaseous solutions. Depending on the question and data given that could help decide whether to use Kp or Kc.
- Sun Jan 12, 2020 10:05 pm
- Forum: Ideal Gases
- Topic: Topics on Test 1
- Replies: 37
- Views: 1252
Re: Topics on Test 1
Test 1 will most likely cover the objectives from outline 1, which deals with chemical equilibrium. To study I would look over the problem sets along with the videos posted on the class websites. I would also make sure to do all the problems listed by the outlines to make sure that you have a firm g...
- Sun Jan 12, 2020 10:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units for K
- Replies: 21
- Views: 589
Re: Units for K
K is a constant, meaning there are no units used. But, it is a good way to check your work if you end up with units because there should not be any because they should all cancel out.
- Sun Dec 08, 2019 1:15 am
- Forum: Lewis Acids & Bases
- Topic: Lewis vs Bronsted
- Replies: 7
- Views: 605
Re: Lewis vs Bronsted
Lewis acids are lone pair acceptors. Lewis bases are lone pair donors. Bronsted acids are H+ donors. Bronsted bases are H+ acceptors. Bronsted acids are most always the same as Lewis bases because they always accept a proton by donating a lone pair. Bronsted acids are a special kind of Lewis acid be...
- Sun Dec 08, 2019 1:12 am
- Forum: Lewis Acids & Bases
- Topic: how to identify lewis acids
- Replies: 3
- Views: 331
Re: how to identify lewis acids
A lewis acid is anything that is able to take in a lone electron pair. Usually it has a positive charge or can be a expanded octet.
- Sun Dec 08, 2019 1:08 am
- Forum: Air Pollution & Acid Rain
- Topic: Options to reduce acid rain
- Replies: 8
- Views: 550
Re: Options to reduce acid rain
To reduce acid rain sanctions can be put in place on fossil fuel usage and power plants.
- Sun Dec 08, 2019 1:03 am
- Forum: Industrial Examples
- Topic: Coordination compounds as Chemotherapy drugs
- Replies: 9
- Views: 1770
Re: Coordination compounds as Chemotherapy drugs
The main drug discussed in class was cisplatin. Which is square planar and has 2 amine groups on one side and 2 chloride groups on the other side.
- Fri Dec 06, 2019 9:01 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Topics
- Replies: 2
- Views: 165
Final Topics
What topics would you suggest to focus on for the final? Did anyone's TA give them a specific list of what type of problems or topics to study/ focus on?
- Sun Dec 01, 2019 11:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent Shape
- Replies: 31
- Views: 2834
Re: Bent Shape
Bent can have either one lone pair: which makes an electron geometry of trigonal planar because three things around the central atom and therefore a molecular geometry of bent. it can also have two lone pairs: which makes an electron geometry of tetrahedral because 4 things around the central atom a...
- Sun Dec 01, 2019 11:28 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma vs. Pi
- Replies: 20
- Views: 1176
Re: Sigma vs. Pi
Sigma bonds would be stronger because of the overlapping orbitals while pi bonds don't have this overlap.
- Sun Dec 01, 2019 11:25 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Advice for studying
- Replies: 92
- Views: 6502
Re: Advice for studying
I usually read the textbook and any concepts I have issues with I look for videos on Khan Academy!
- Sun Dec 01, 2019 11:24 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions to Electroaffinity
- Replies: 3
- Views: 351
Re: Exceptions to Electroaffinity
I think as long as you know the general trends of electronegativity that should suffice. If there are weird patterns that might not seem obvious my TA said the test would include numbers of electronegativity to help.
- Sun Dec 01, 2019 11:17 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Content of the final
- Replies: 11
- Views: 970
Re: Content of the final
I don't recall covering this so far, but I guess we will see on Wednesday!
- Sun Nov 24, 2019 11:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs linear
- Replies: 56
- Views: 4048
Re: Bent vs linear
Look to see the electron geometries and molecular shapes to help you decide! For example if there are 2 atoms bonded and 1 electron then it is bent, if there are 2 atoms and 2 electrons it is also bent, if there are 2 atoms and 3 electrons it is linear because the lone pairs balance eachother out.
- Sun Nov 24, 2019 11:49 pm
- Forum: Hybridization
- Topic: sigma or pi?
- Replies: 20
- Views: 1100
Re: sigma or pi?
A sigma bond is any single bond in a molecule, including 1 out of the 2 bonds in a double bond and 1 out of the 3 bonds in triple bonds. A pi bond is any 2nd or 3rd bond in a double or triple bond.
- Sun Nov 24, 2019 11:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: AXE Format
- Replies: 34
- Views: 1086
Re: AXE Format
You don't have to write subscribts for X or E if it is 1. Only for 2 and above!
- Sun Nov 24, 2019 11:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Hydrogen Bonding
- Replies: 13
- Views: 652
Re: Hydrogen Bonding
Yes, because in the ranking of powers of IMF's hydrogen bonding is a specialized kind of dipole-dipole bonding which is actually stronger, so if a molesule has H bonding it will be polar.
- Sun Nov 24, 2019 11:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-shape
- Replies: 21
- Views: 1601
Re: T-shape
T shaped is when the electron geometry is trigonal bipyrimidal because there are 5 regions of electron density around the CE and the Molecular shape is t-shaped because 3/5 of the regions of electron density are atoms and 2/5 are lone pairs.
- Sun Nov 17, 2019 10:23 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
How often do I tell chemistry jokes on here?
~periodically~
~periodically~
- Sun Nov 17, 2019 10:22 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
What kind of dogs do chemists have?
~laboratory retreivers~
~laboratory retreivers~
- Sun Nov 17, 2019 10:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 8 HW
- Replies: 4
- Views: 275
Re: Week 8 HW
Ya it looks like the HW problems from outline 4 because it will be tested this week in discussion!
- Sun Nov 17, 2019 10:07 pm
- Forum: Electronegativity
- Topic: Formula for Difference
- Replies: 7
- Views: 481
Re: Formula for Difference
I think the majority of what we will have to know are the basic trends. They also might give us numbers though if there are certain elements that don't stick to the status quo.
- Sun Nov 17, 2019 10:01 pm
- Forum: General Science Questions
- Topic: Chemistry Community Questions
- Replies: 5
- Views: 401
Re: Chemistry Community Questions
I'm pretty sure it's graded on a weekly scale, but I'm not sure. I'll ask my TA and get back to you.
- Sun Nov 17, 2019 9:56 pm
- Forum: General Science Questions
- Topic: Test 2 Review
- Replies: 8
- Views: 596
Re: Test 2 Review
My TA said
IMF, H bonding, molecular shape, VSPER, polarity from VSPER structure, bond angles, polar/non polar, intro sigma and pi bonds
IMF, H bonding, molecular shape, VSPER, polarity from VSPER structure, bond angles, polar/non polar, intro sigma and pi bonds
- Sun Nov 10, 2019 11:00 pm
- Forum: Octet Exceptions
- Topic: Octet Rule exceptions
- Replies: 14
- Views: 825
Re: Octet Rule exceptions
Yes some examples are H, He, Li, Be, B, and Al.
- Sun Nov 10, 2019 10:54 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing This Equation
- Replies: 11
- Views: 1052
Re: Balancing This Equation
combustion equations always have O2 on the reactant side and CO2 and H2O on the other, sometimes N2 depending on the organic molecule. 2C10H14N2 +27O2 ------> 20CO2+ 14H2O + 7N2
- Sun Nov 10, 2019 10:45 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge and Resonance
- Replies: 5
- Views: 382
Re: Formal Charge and Resonance
Formal charges help you find the most probable structure and from there you can see if there could be resonance structures of that structure.
- Sun Nov 10, 2019 10:42 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Writing e- Configurations
- Replies: 15
- Views: 621
Re: Writing e- Configurations
I think they would tell you to write out the whole e- config or the short-hand one. They would definitely specify which to use.
- Sun Nov 10, 2019 10:39 pm
- Forum: Ionic & Covalent Bonds
- Topic: London Dispersion
- Replies: 13
- Views: 641
Re: London Dispersion
London dispersion forces happen because electrons moving can induce dipole forces due to attraction.
- Sun Nov 03, 2019 8:15 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
This is kind of a joke but my class and I made a periodic table with pictures of literal moles, like the animal, and gave it to my teacher for April fools in high school. Kinda funny she was dying laughing.
- Sun Nov 03, 2019 8:12 pm
- Forum: Electronegativity
- Topic: Electron affinity vs electronegativity
- Replies: 4
- Views: 244
Re: Electron affinity vs electronegativity
Electronegativity is the strength of an atom to attract an electron in a compound ex. in H2O oxygen has a electronegativity giving the oxygen a partial negative charge and the hydrogens a partial positive charge. Electron affinity is the energy released when an electron is added to an atom ex. Flour...
- Sun Nov 03, 2019 8:06 pm
- Forum: Dipole Moments
- Topic: Dipole moment
- Replies: 3
- Views: 185
Re: Dipole moment
yes. Non-polar molecules experience forces called Van Der Walls forces, which create a small dipole moment for a tiny amount of time when there is a difference in charge between two molecules. More polar molecules experience stronger dipole moments because of their innate polarity, meaning these for...
- Sun Nov 03, 2019 8:01 pm
- Forum: Electronegativity
- Topic: definitions
- Replies: 8
- Views: 465
Re: definitions
electron affinity is the atoms affinity or how much an atom wants an electron and the energy it gives off when it obtains an electron. Ionization energy is the energy it takes to take away an electron from an atom. Usually, these trends follow a similar pathway on the periodic table as atoms who hav...
- Sun Nov 03, 2019 7:56 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic character in covalent bonds
- Replies: 3
- Views: 278
Re: Ionic character in covalent bonds
The stronger the bond in covalent molecules, the more ionic character it possesses. So look for molecules with a difference in electronegativity to tell the strength of the bond. If they are similar it will not be as ionic, if they are different it will act more ionic.
- Sun Oct 27, 2019 8:45 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: p-orbitals
- Replies: 11
- Views: 390
Re: p-orbitals
I don't think it is a requirement to use x, y, z. You should only have to write it as whatever quantum number it is and then "p".
- Sun Oct 27, 2019 8:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: How to find my posts
- Replies: 163
- Views: 161113
Re: How to find my posts
You can also post a comment and then scroll down to the comment you made and click on the number of posts you made and then it will tell you the date and time you posted.
- Sun Oct 27, 2019 2:12 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 9
- Views: 379
Re: Ionization Energy
It is positive because ionization energy is the amount of energy required to remove an electron, which requires an input of energy. And it depends on the number of electrons and the number of subshells filled generally when dealing with ionization energies.
- Sun Oct 27, 2019 2:06 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: What's the difference between subshell vs orbitals?
- Replies: 8
- Views: 624
Re: What's the difference between subshell vs orbitals?
Subshells are either s,p,d, or f on the periodic table.
Orbitals are inside subshells.
for example: s has 1 orbital, p has 3 orbitals, d has 5 orbitals, and f has 7 orbitals that each hold 2 electrons.
Orbitals are inside subshells.
for example: s has 1 orbital, p has 3 orbitals, d has 5 orbitals, and f has 7 orbitals that each hold 2 electrons.
- Sun Oct 27, 2019 2:00 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: oribital numbers
- Replies: 7
- Views: 228
Re: oribital numbers
What helps me is looking at the periodic table and counting how many atoms are in each subshell and pretending they are electrons, for example: for s subshells there are 2 atoms on the periodic table (2 electrons), in the p subshells there are 6 atoms on the periodic table (6 electrons), in the d su...
- Sun Oct 20, 2019 2:14 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic radii
- Replies: 9
- Views: 503
Re: Atomic radii
This has to do with the number of valence electrons along with the increasing number of protons in the nucleus as you go from left to right across the periodic table. This trend causes the protons to have a greater pull over the electrons, thus leading to a smaller atomic radius.
- Sun Oct 20, 2019 2:11 pm
- Forum: Einstein Equation
- Topic: why do we use these equations?
- Replies: 5
- Views: 266
Re: why do we use these equations?
Based on the question and the given information, it's kind of like a puzzle where you can use certain equations or combine them to get the information you are looking for!
- Sun Oct 20, 2019 2:07 pm
- Forum: Einstein Equation
- Topic: E=hv [ENDORSED]
- Replies: 52
- Views: 18069
Re: E=hv [ENDORSED]
E represents the energy of the photon, as it is the constant times the wavelength.
- Sun Oct 20, 2019 2:01 pm
- Forum: Photoelectric Effect
- Topic: if KE is 0 how can the electron be ejected?
- Replies: 4
- Views: 228
if KE is 0 how can the electron be ejected?
How is the electron ejected if the energy of the photon is equal to that of the work function, meaning it has no KE? Because wouldn't it not be able to move if it has 0 KE?
- Sun Oct 20, 2019 1:56 pm
- Forum: *Black Body Radiation
- Topic: Will this concept be tested
- Replies: 8
- Views: 1173
Re: Will this concept be tested
I'm pretty sure they are talking about black bodies. And I am not 100% sure if it will be tested ill ask my TA and get back to you! I don't think it will though because there is no module for black bodies on the class website and I think those are like the main concepts we need to know.
- Sun Oct 20, 2019 1:52 pm
- Forum: Properties of Light
- Topic: Unit for Wavelength
- Replies: 34
- Views: 2300
Re: Unit for Wavelength
Hi! It seems mostly the wavelength, distance from peak to peak, is measured in nm, nanometers, on most of the diagrams in the book for the EM spectrum. But I'm sure maybe the tests will have us convert units to use in other equations.
- Sun Oct 13, 2019 3:21 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 416530
Re: Rusty on High School Chem [ENDORSED]
I literally love this youtube channel for chemistry, I used it all throughout AP and regular chem in high school. His name is Tyler Dewitt. He is so succinct and I like his videos way better than crash course or any other teaching resource. Sometimes he can be a little slow so I usually watch on 1.5...
- Sun Oct 13, 2019 3:11 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3007162
Re: Post All Chemistry Jokes Here
Here is one i found that sent me: Old chemists never die. They just stop reacting!
- Sun Oct 13, 2019 3:07 pm
- Forum: Trends in The Periodic Table
- Topic: Chemistry Community
- Replies: 8
- Views: 460
Re: Chemistry Community
Ya I think as long as you can see the number of posts and the dates they were posted on it should be fine so even if there is a grading error there is still proof that you posted in the correct time frame.
- Sun Oct 13, 2019 3:03 pm
- Forum: Properties of Light
- Topic: Photon Model
- Replies: 3
- Views: 169
Re: Photon Model
I like to think of photons like beads on a necklace or string, and each bead is a photon.