Search found 102 matches
- Mon Mar 08, 2021 2:40 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: What is frequency factor
- Replies: 10
- Views: 801
Re: What is frequency factor
I believe it tells you the percent of collisions that occur with the correct orientation.
- Mon Mar 08, 2021 2:38 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Frequency Factor
- Replies: 3
- Views: 203
Re: Frequency Factor
If the collisions aren't in the correct orientation, then there won't be a reaction.
- Wed Mar 03, 2021 12:09 pm
- Forum: Student Social/Study Group
- Topic: Spring Break
- Replies: 53
- Views: 3177
Re: Spring Break
just relaxing and spending time with my family
- Sat Feb 27, 2021 4:06 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Sapling #17 Week 7/8
- Replies: 8
- Views: 431
Re: Sapling #17 Week 7/8
You use the Nernst equation to calculate E.
- Sat Feb 27, 2021 4:05 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Shorthand
- Replies: 5
- Views: 275
Re: Cell Shorthand
The single lines indicate an interface between phases that are in contact with each other. For example, in my question, Pb and PbCl2 were on one side while Ag and AgCl2 were on the other side. Here, Pb and PbCl2 would be separated by a single and Ag and AgCl2 would be separated by a single line.
- Sat Feb 27, 2021 4:03 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic vs electrolytic cells
- Replies: 1
- Views: 125
Re: Galvanic vs electrolytic cells
In galvanic cells, the (spontaneous) redox reaction is powering the electric current whereas in electrolytic cells, the electric current is powering a non spontaneous redox reaction.
- Sat Feb 27, 2021 1:40 pm
- Forum: Student Social/Study Group
- Topic: Chem Community Points
- Replies: 35
- Views: 1435
Re: Chem Community Points
You need to have 50 points by the end of the quarter and having more than 50 doesn't give you extra credit.
- Sat Feb 27, 2021 1:39 pm
- Forum: Student Social/Study Group
- Topic: Chem 14 BL
- Replies: 7
- Views: 497
Re: Chem 14 BL
The workload is very manageable and Dr. Casey is an amazing professor! But regardless of the professor, the class is fairly easy. Almost all of the concepts are things that we've covered in chem 14a or 14b, and the few concepts that we haven't covered are very easy to understand.
- Sat Feb 13, 2021 3:57 pm
- Forum: Student Social/Study Group
- Topic: Chem 14C Question
- Replies: 8
- Views: 528
Re: Chem 14C Question
On the class planner, it says that they will be online but not recorded, but I don't know if this is necessarily the case.
- Sat Feb 13, 2021 3:44 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: equilibrium
- Replies: 6
- Views: 311
Re: equilibrium
I think that this is because work is done in order to achieve equilibrium or at least move closer to equilibrium. And so if the reaction is already at equilibrium, it doesn't do any work.
- Sat Feb 13, 2021 3:32 pm
- Forum: Student Social/Study Group
- Topic: Classes for next quarter?
- Replies: 165
- Views: 13098
Re: Classes for next quarter?
I'm taking Chem 14C, Physics 5C, and a GE. I was going to take Chem 14CL too but it's filling up pretty fast.
- Tue Feb 02, 2021 9:36 pm
- Forum: Student Social/Study Group
- Topic: Test curve?
- Replies: 40
- Views: 2830
Re: Test curve?
Lavelle hasn't ever mentioned curving test grades, so I don't think that it's very likely.
- Tue Feb 02, 2021 9:35 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity units
- Replies: 3
- Views: 176
Re: Heat capacity units
This is because one degree unit on the Celsius scale is equivalent to one degree unit on the Kelvin scale. So, as long as all your temperatures are in Celsius or all your temperatures are in Kelvin, it doesn't matter which you use.
- Tue Feb 02, 2021 1:22 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Postive vs. negative work
- Replies: 18
- Views: 941
Re: Postive vs. negative work
When work is done by a system, the system is using energy, meaning that energy is being released from the system to the surroundings, which is why work is negative. When work is done to a system, the system is gaining energy from the surroundings, so work is positive.
- Tue Feb 02, 2021 12:55 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Week 3/4 Sapling #9
- Replies: 13
- Views: 670
Re: Week 3/4 Sapling #9
How should we determine the delta T when applying the q=mcdeltaT equation in this problem, since final temperature is not given because it is what we need to solve for? delta T would be T(final) minus T(initial), and since you know T(initial), when you use q = -q, you can solve for T(final). So, yo...
- Tue Feb 02, 2021 12:51 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Heat Change conceptual question
- Replies: 9
- Views: 551
Re: Heat Change conceptual question
Isn't delta H negative when the reaction is exothermic, meaning heat is released from the solution?
- Tue Feb 02, 2021 12:49 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Week 3/4 Sapling #12
- Replies: 2
- Views: 162
Re: Week 3/4 Sapling #12
For part A, you find q by multiplying the number of moles you have by the heat of combustion. Then you find the heat capacity of the calorimeter (C) by dividing q by the change in temperature. For part B, you use the equation q = C(delta T). And since it asks for the heat combustion, you divide q by...
- Sun Jan 31, 2021 11:28 pm
- Forum: Student Social/Study Group
- Topic: 14BL
- Replies: 1
- Views: 126
Re: 14BL
It's not too difficult. I'm not sure how hard the exams are since we haven't had our midterm yet, but the homework is very manageable. You usually have one group lab activity and an individual lab report every week.
- Sun Jan 31, 2021 3:08 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Labs
- Replies: 10
- Views: 489
Re: Labs
I'm not sure what most people do, but I'm taking 14BL right now and I'm planning on taking 14CL next quarter with chem 14C. Has it been hard to manage 14BL with 14B? Nervous about taking 14C and BL together next quarter but feel like I don't have much a choice. No it actually hasn't been too hard, ...
- Sun Jan 31, 2021 2:59 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: How to calculate change in temperature
- Replies: 3
- Views: 242
Re: How to calculate change in temperature
You use the equation q = mcΔT. The heat gained by the cold water is equal to the heat lost by the hot water, so q for the cold water is equal to negative q for the hot water.
- Sun Jan 31, 2021 2:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Labs
- Replies: 10
- Views: 489
Re: Labs
I'm not sure what most people do, but I'm taking 14BL right now and I'm planning on taking 14CL next quarter with chem 14C.
- Sat Jan 30, 2021 7:59 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: perfect system
- Replies: 20
- Views: 779
Re: perfect system
This means that the heat of the surroundings has to equal the heat of the system. For example, if 200 J of heat was released from the system (meaning it left the system), this means that 200 J of heat was added to the surroundings.
- Sat Jan 30, 2021 7:58 pm
- Forum: Student Social/Study Group
- Topic: Go treat yourself after MT1!
- Replies: 75
- Views: 4244
Re: Go treat yourself after MT1!
I watched netflix and then caught up on homework for my other classes :)
- Mon Jan 25, 2021 5:25 pm
- Forum: Significant Figures
- Topic: Can subtracting reduce the number of Significant Figures a number has?
- Replies: 4
- Views: 3702
Re: Can subtracting reduce the number of Significant Figures a number has?
Your rounded answer should have 4 sig figs which would be 4.044*10^-5 mol because when you divide, the number of significant figures in the answer should match the number of significant figures of the least precisely known number used in the calculation, meaning the number with the fewest sig figs. ...
- Mon Jan 25, 2021 5:22 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Perfect Systems
- Replies: 2
- Views: 183
Re: Perfect Systems
Since he didn't mention a non-perfect system, I would assume the system is always a perfect system, unless stated otherwise.
- Mon Jan 25, 2021 5:21 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Monday 1/25 Lecture Clarification - Exothermic Neutralization
- Replies: 3
- Views: 164
Re: Monday 1/25 Lecture Clarification - Exothermic Neutralization
Yes, I think generally all neutralization reactions are exothermic because every neutralization reaction involves the formation of water which releases heat, making it exothermic.
- Mon Jan 25, 2021 5:19 pm
- Forum: Student Social/Study Group
- Topic: Questions about Friday/Midterm
- Replies: 7
- Views: 211
Re: Questions about Friday/Midterm
Yes, that's what it means.
- Mon Jan 25, 2021 1:30 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Change in Kelvin/Celsius
- Replies: 4
- Views: 229
Re: Change in Kelvin/Celsius
The units of Kelvin and Celsius are essentially the same in that a temperature in Kelvin is just the temperature in Celsius + 273.15. So, for example, an increase of one Kelvin is the same as an increase of one degree Celsius.
- Mon Jan 25, 2021 1:28 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: constant p calorimeter vs. constant v calorimeter
- Replies: 3
- Views: 111
Re: constant p calorimeter vs. constant v calorimeter
If you're working with gases then for the constant pressure calorimeter, you use the molar heat capacity of a gas at constant pressure (Cp) and for the constant volume calorimeter, you use the molar heat capacity of a gas at constant volume (Cv).
- Mon Jan 25, 2021 1:25 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Enthalpy of Formation
- Replies: 10
- Views: 419
Re: Standard Enthalpy of Formation
I think that's something we need to look up or we'll be given it.
- Mon Jan 25, 2021 1:14 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Ice melting
- Replies: 5
- Views: 300
Re: Ice melting
I think this would be considered exothermic because the reaction itself is releasing heat which then causes the temperature of the surroundings to increase. Because the reaction is releasing heat, it is considered exothermic.
- Mon Jan 25, 2021 12:16 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Specific vs. Molar Heat Capacity
- Replies: 3
- Views: 132
Re: Specific vs. Molar Heat Capacity
Kelvin is always interchangeable with Celsius because raising the temperature of a substance by one degree Celsius is the same as raising the temperature by one Kelvin.
- Mon Jan 25, 2021 11:24 am
- Forum: Student Social/Study Group
- Topic: Favorite Music
- Replies: 113
- Views: 9820
Re: Favorite Music
I listen to mostly alt rock and indie :) Some of my favorites are Arctic Monkeys, Cage the Elephant, Wallows, Clairo, and Surf Curse.
- Wed Jan 13, 2021 12:58 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Weak & Strong Acids/Bases
- Replies: 6
- Views: 292
Re: Weak & Strong Acids/Bases
You more or less just have to memorize all the strong acids and bases and anything that isn't a strong base or acid is considered weak.
- Tue Jan 12, 2021 2:07 pm
- Forum: Student Social/Study Group
- Topic: New Year Resolutions?
- Replies: 54
- Views: 2548
Re: New Year Resolutions?
procrastinate less and meditate and do yoga more often
- Mon Jan 11, 2021 8:30 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Getting two positive x values when using quadratic
- Replies: 43
- Views: 4596
Re: Getting two positive x values when using quadratic
Hi, so from lecture, Dr. Lavelle talks about how we use the quadratic formula to solve for the x change value in ICE tables, and then proceeds to show how we omit the negative x value and use the positive one. What happens when we get two positive x values? Would we test both x values into the ICE ...
- Mon Jan 11, 2021 8:27 pm
- Forum: Student Social/Study Group
- Topic: Comfort Movies
- Replies: 168
- Views: 22337
Re: Comfort Movies
I love watching all the Harry Potter movies :) and also Coraline is one of my favorites too.
- Mon Jan 11, 2021 8:24 pm
- Forum: Ideal Gases
- Topic: Lecture 3 Problem
- Replies: 7
- Views: 214
Re: Lecture 3 Problem
He does this to find the concentration. In the example there's 1.5 moles of PCL5 in a 0.5 L reaction vessel. So to find the concentration, you divide the moles by the volume which would be 1.5/0.5.
- Mon Jan 11, 2021 8:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When to use Kw
- Replies: 4
- Views: 446
Re: When to use Kw
Kw is the autoprotolysis constant of water at 25 degrees Celsius, so it's only used for the reaction where water is forming hydroxide (OH-) and/or hydronium (H3O+) ions. You'd typically use it to find the concentration of H30+ or OH-.
- Sun Jan 10, 2021 3:33 pm
- Forum: Student Social/Study Group
- Topic: Chemistry Community
- Replies: 29
- Views: 1117
Re: Chemistry Community
I don't think there's really a strict deadline, as long as you have 50 posts by the end of the quarter.
- Thu Jan 07, 2021 11:03 pm
- Forum: Student Social/Study Group
- Topic: Study Habits
- Replies: 96
- Views: 5414
Re: Study Habits
I've found that doing the textbook problems has helped me a lot. I'd also suggest spreading out your studying and not just cram right before the midterms and final. Going to step up sessions and peer learning sessions can also be very helpful if there's something in particular that you're struggling...
- Thu Jan 07, 2021 9:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: R value
- Replies: 5
- Views: 344
Re: R value
It depends on the units that you're given, but I think we'll typically be using either one of those values.
- Thu Jan 07, 2021 8:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Audio-Visual Topics
- Replies: 13
- Views: 523
Re: Audio-Visual Topics
I don't think there'll be any other audio-visual topics. The main forms of practice would be the Sapling homework problems and the textbook problems.
- Thu Jan 07, 2021 7:54 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc
- Replies: 11
- Views: 301
Re: Kc
I think typically the answer is yes because when we're using ICE tables, the goal is usually to find the concentrations in order to calculate Kc and so you'd want to use molarity for the table.
- Thu Jan 07, 2021 6:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling Problem: Used non-UCLA email address for previous quarter
- Replies: 5
- Views: 280
Re: Sapling Problem: Used non-UCLA email address for previous quarter
I've heard that trying it through a different browser might help.
- Thu Jan 07, 2021 6:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling Assignments
- Replies: 30
- Views: 1677
Re: Sapling Assignments
Hi, I was wondering if anyone knew if the Sapling questions were due this coming Sunday as in three days from now, or if it is due next Sunday as in a week and three days from now. I know Sapling says that the first assignment is due Sunday of week 2, but I did not want miss anything, so if someone...
- Thu Jan 07, 2021 12:13 pm
- Forum: Ideal Gases
- Topic: What makes an ideal gas an ideal gas?
- Replies: 9
- Views: 309
Re: What makes an ideal gas an ideal gas?
Just a small correction to what was said above, an ideal gas won't turn into a liquid when the temperature is lowered (not raised).
- Wed Jan 06, 2021 11:08 pm
- Forum: Student Social/Study Group
- Topic: Groupme for 14B
- Replies: 5
- Views: 197
Re: Groupme for 14B
This is the groupme for Chem 14b with Lavelle: https://groupme.com/join_group/62288203/dSSkobMS
- Wed Jan 06, 2021 2:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: solvent in equilibrium constants
- Replies: 8
- Views: 350
Re: solvent in equilibrium constants
A solvent is typically a liquid (l), such as water, and it is not included when calculating the equilibrium constant.
- Tue Jan 05, 2021 7:43 pm
- Forum: Student Social/Study Group
- Topic: Group Me
- Replies: 2
- Views: 298
- Tue Jan 05, 2021 1:14 pm
- Forum: Student Social/Study Group
- Topic: Chem 14B
- Replies: 1
- Views: 206
- Sat Dec 12, 2020 5:00 pm
- Forum: Amphoteric Compounds
- Topic: Textbook Question 6A.17
- Replies: 3
- Views: 257
Re: Textbook Question 6A.17
Metalloid oxides are generally amphoteric but this doesn't mean that all amphoteric compounds are metalloid oxides. Bi2O3 is an amphoteric compound because it has both basic and acidic characters.
- Sat Dec 12, 2020 4:54 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals and Their Nodal Planes
- Replies: 7
- Views: 593
Re: Orbitals and Their Nodal Planes
P-orbitals have one nodal plane, and d-orbitals have two nodal planes.
- Thu Dec 03, 2020 5:33 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Denticity
- Replies: 2
- Views: 79
Re: Denticity
Denticity refers to the number of donor groups in a single ligand that bind to a central atom in a coordination complex. For example, if a ligand binds at one site, meaning it donates 1 electron pair, it is said to be monodentate. Denticity basically just refers to how many site a ligand binds to, o...
- Wed Dec 02, 2020 11:46 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acids and Bases
- Replies: 7
- Views: 205
Re: Bronsted Acids and Bases
I think that it's just another way of defining acids and bases. A Bronsted acid means that it is a proton donor and a Bronsted base means that it is a proton acceptor. Similar to how a Lewis acid means that that species accepts an electron pair and a Lewis base means that that species donates an ele...
- Wed Dec 02, 2020 5:35 pm
- Forum: Biological Examples
- Topic: Co - VitB12
- Replies: 7
- Views: 442
Re: Co - VitB12
Cobalt is in the vitamin.
- Wed Dec 02, 2020 4:32 pm
- Forum: Student Social/Study Group
- Topic: Thoughts on Switching Majors?
- Replies: 35
- Views: 2192
Re: Thoughts on Switching Majors?
I'm a biology major and honestly the main reason I chose it is because the requirements for my major line up with the requirements for medical school and I don't really have a strong passion for any other subject. But I think you should major in whatever interests you or whatever you're passionate a...
- Wed Dec 02, 2020 2:53 pm
- Forum: Naming
- Topic: Iron naming
- Replies: 1
- Views: 75
Re: Iron naming
I think in that case it would just be called iron.
- Sun Nov 29, 2020 11:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles
- Replies: 5
- Views: 403
Re: Bond angles
Yes, the equatorial bond angles are 120° and the axial bond angles are 90° and 180°.
- Sun Nov 29, 2020 5:59 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Weekly Discussion grades
- Replies: 9
- Views: 313
Re: Weekly Discussion grades
oh got it! So do I have to have all 5 posts every week or I disperse the number of posts whenever, but make sure I have 40 by the end of this week? You need to have 50 posts in total by the end of the quarter (by the end of week 10). And you can post whenever, it doesn't have to be strictly 5 per w...
- Sat Nov 28, 2020 11:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: sigma vs pi bonds
- Replies: 33
- Views: 1989
Re: sigma vs pi bonds
All single bonds are sigma bonds. A double bond has one sigma bond and one pi bond. And a triple bond has one sigma bond and two pi bonds.
- Mon Nov 23, 2020 3:41 pm
- Forum: Student Social/Study Group
- Topic: Exercising Our Minds and Bodies
- Replies: 120
- Views: 15240
Re: Exercising Our Minds and Bodies
I go on walks with my dogs and my family and sometimes I do yoga.
- Fri Nov 20, 2020 2:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chem 14BL
- Replies: 5
- Views: 238
Re: Chem 14BL
Yes, you can take Chem 14BL after you take Chem 14b, they don't have to be taken at the same time.
- Fri Nov 20, 2020 2:11 pm
- Forum: Dipole Moments
- Topic: Dipole Moments Cancelling out
- Replies: 10
- Views: 1028
Re: Dipole Moments Cancelling out
For the dipoles to cancel out, they must point in opposite directions. In cis-dichloroethene, the dipoles are pointing in different directions but they are not completely opposite. In other words, the directions of the dipoles must be 180 degrees apart for them to cancel out.
- Wed Nov 18, 2020 6:37 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: Magnitude of Hydrogen and Dispersion Forces
- Replies: 4
- Views: 274
Re: Magnitude of Hydrogen and Dispersion Forces
Yes that's what they're referring to.
- Mon Nov 16, 2020 4:59 pm
- Forum: Lewis Structures
- Topic: electron configuration
- Replies: 4
- Views: 230
Re: electron configuration
Having ten electrons in the d sub shell is more favorable than filling the s sub shell, so in this case, the electrons would fill up the d sub shell before the s.
- Tue Nov 10, 2020 11:01 pm
- Forum: Dipole Moments
- Topic: Dipole-dipole and london-dispersion IMF
- Replies: 7
- Views: 288
Re: Dipole-dipole and london-dispersion IMF
London dispersion forces occur between all atoms and molecules whereas dipole-dipole interactions can only occur between molecules that have dipoles.
- Tue Nov 10, 2020 6:46 pm
- Forum: General Science Questions
- Topic: Midterm 1 Review
- Replies: 3
- Views: 348
Re: Midterm 1 Review
I think if you go to your TA's office hours (or any TA's office hours) you can review Midterm 1 with them.
- Tue Nov 10, 2020 6:44 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 1E.13
- Replies: 1
- Views: 52
Re: 1E.13
Ag has 11 more electrons than Kr, so you would start with the electron configuration for Kr which is represented by [Kr] and then fill the following shells with the remaining 11 electrons. [Kr] = 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶ so the orbitals that come after this are 4d and 5s. Typically, you'd fill the ...
- Tue Nov 10, 2020 11:51 am
- Forum: Administrative Questions and Class Announcements
- Topic: missing discussion
- Replies: 4
- Views: 191
Re: missing discussion
Discussion sections don't affect your grade, they're really just for extra practice.
- Sun Nov 08, 2020 12:22 pm
- Forum: Student Social/Study Group
- Topic: Participation
- Replies: 56
- Views: 2720
Re: Participation
The points through week 4 are posted on CCLE under Grades. If you've been posting 5 times a week, then you should have a total of 20 points. By the end of the quarter you need 50 points, which means you need a total of 50 posts.
- Thu Nov 05, 2020 1:45 pm
- Forum: Student Social/Study Group
- Topic: Studying Tips
- Replies: 23
- Views: 840
Re: Studying Tips
For me, doing the textbook questions was very helpful, as well as reviewing my notes on the lectures.
- Wed Nov 04, 2020 1:32 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: l numbers bigger than 3
- Replies: 5
- Views: 316
Re: l numbers bigger than 3
l can be any integer between 0 and n-1. So if n=6, then l can be anywhere between 0 and 5.
- Tue Nov 03, 2020 7:32 pm
- Forum: Lewis Structures
- Topic: Only 4 Pairs
- Replies: 3
- Views: 171
Re: Only 4 Pairs
Lewis structures show the number of valence electrons each atom has, and each atom can typically only have eight valence electrons at most (with some exceptions), hence the maximum of 4 lone pairs. This goes for all elements, transition metals included.
- Tue Nov 03, 2020 3:17 pm
- Forum: Lewis Structures
- Topic: Monday Lecture
- Replies: 3
- Views: 246
Re: Monday Lecture
I think that was a mistake. Oxygen does have a lower ionization energy than nitrogen.
- Mon Nov 02, 2020 10:04 pm
- Forum: Trends in The Periodic Table
- Topic: # of electrons
- Replies: 23
- Views: 616
Re: # of electrons
The number of electrons an element has is equal to its atomic number.
- Mon Nov 02, 2020 10:03 pm
- Forum: Lewis Structures
- Topic: sides
- Replies: 12
- Views: 549
Re: sides
I think you can put them on any side, I don't think it matters.
- Mon Nov 02, 2020 10:03 pm
- Forum: Lewis Structures
- Topic: charge by square bracket
- Replies: 8
- Views: 1650
Re: charge by square bracket
It's just the charge of the molecule. So when writing the Lewis structure for the molecule NO3-, you would put brackets around the structure and a minus in the top right corner. It just depends on the charge of the molecule. For example, if the molecule's charge was +1, you'd put a + in the corner o...
- Mon Nov 02, 2020 8:11 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 4s before 3d Orbital
- Replies: 11
- Views: 488
Re: 4s before 3d Orbital
It means the 4s orbital is filled before the 3d orbital. When you write out the electron configuration, though, the 3d is still written before the 4s (ex. scandium would be written as [Ar]3d^1 4s^2) even though the 4s gets filled first.
- Mon Nov 02, 2020 1:50 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Z electrons
- Replies: 3
- Views: 135
Re: Z electrons
Z means the atomic number of an element. So for example, the atomic number of hydrogen is 1, so you would add 1 electron to the electron configuration.
- Mon Oct 26, 2020 6:32 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 17505
Re: How are you studying?
Javier Perez M 2J wrote:Will we be provided with conversion units for the exam? (such as how many nanometers are in a meter and ml in a liter)
Or are we expected to memorize this?
Some conversions are on the constants and equations sheet, like kg to g, angstroms to meters, nanometers to meters, and picometers to meters.
- Mon Oct 26, 2020 6:29 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 17505
Re: How are you studying?
I've been taking notes on all the lectures and doing all of the practice textbook questions assigned in the syllabus.
- Mon Oct 26, 2020 6:28 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra wave-like or particle-like properties
- Replies: 3
- Views: 94
Re: Atomic Spectra wave-like or particle-like properties
I'm not entirely sure, but I think light behaves like a particle, since the atomic spectra experiment has to do with photons of energy which would behave as particles, not waves.
- Mon Oct 26, 2020 6:26 pm
- Forum: General Science Questions
- Topic: assuming limiting reactant
- Replies: 4
- Views: 380
Re: assuming limiting reactant
Since there's no way to know how much H2O you began with, I think it's safe to assume that PCl3 is the limiting reagent.
- Mon Oct 26, 2020 5:56 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Potassium & Calcium Electron Configurations
- Replies: 1
- Views: 97
Re: Potassium & Calcium Electron Configurations
He was talking about how the 4s orbital is occupied before the 3d orbital, but this doesn't change the way we write the electron configuration. You'd still write 3d before 4s, for example scandium would be: [Ar] 3d^1 4s^2. But for potassium and calcium, the 3d orbital isn't occupied, so it'd be writ...
- Sat Oct 24, 2020 9:41 pm
- Forum: DeBroglie Equation
- Topic: How to convert from joules to volts
- Replies: 5
- Views: 154
Re: How to convert from joules to volts
1 Electron volt (eV) = 1.602176565 x 10-19 joules (J)
- Sat Oct 24, 2020 9:40 pm
- Forum: DeBroglie Equation
- Topic: How to convert from joules to volts
- Replies: 5
- Views: 154
Re: How to convert from joules to volts
1 volt (eV) = 1.602176565 x 10^-19 joules (J)
- Tue Oct 20, 2020 6:18 pm
- Forum: Properties of Light
- Topic: Midterm
- Replies: 42
- Views: 1390
Re: Midterm
Since it's multiple choice, there isn't going to be any partial credit. But, according to my TA, there won't be a lot of questions that depend on your answers to previous questions.
- Tue Oct 20, 2020 5:50 pm
- Forum: Photoelectric Effect
- Topic: Sapling Hw #5
- Replies: 4
- Views: 1271
Re: Sapling Hw #5
3.24x10^-20 J is the energy for a single photon. To find the number of photons, you need to divide the heat absorbed by the energy per photon. So you would divide 26.19 J by 3.24x10^-20 J/photon.
- Tue Oct 20, 2020 3:53 pm
- Forum: DeBroglie Equation
- Topic: 1.B21
- Replies: 3
- Views: 170
Re: 1.B21
What I did was convert the 5.15 ounces to kilograms and the 92 mph to meters/second. Then I used the De Broglie equation: wavelength = h/(mass*velocity).
- Tue Oct 20, 2020 3:51 pm
- Forum: DeBroglie Equation
- Topic: 1.B21
- Replies: 3
- Views: 170
Re: 1.B21
I got 1.10 * 10^-34
- Tue Oct 20, 2020 3:22 pm
- Forum: Photoelectric Effect
- Topic: spectral lines
- Replies: 4
- Views: 260
Re: spectral lines
how would we go about calculating the wavelength range?
- Thu Oct 15, 2020 1:39 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Question during Lecture on 10/14
- Replies: 4
- Views: 174
Re: Question during Lecture on 10/14
n is the energy level that the electron is at. the lower the n value, the closer the electron is to the nucleus of the atom and the lower its energy is. When the electron is at n=1, it must absorb energy to move to a higher energy level such as n=2 or n=3. And when the electron is at an energy level...
- Thu Oct 15, 2020 1:34 pm
- Forum: Properties of Light
- Topic: Light Intensity
- Replies: 8
- Views: 179
Re: Light Intensity
I don't think that high frequency necessarily causes a shorter wavelength. But if the frequency is high then this means that the wavelength will be short, and if the frequency is low, that means the wavelength will be long. And different metals do require different energies to eject electrons, so ye...
- Thu Oct 15, 2020 1:31 pm
- Forum: Properties of Light
- Topic: Light Intensity
- Replies: 8
- Views: 179
Re: Light Intensity
And because you need to have a certain wavelength/frequency to eject electrons, increasing the light intensity alone would not cause electrons to be ejected if none were ejected in the first place because increasing the light intensity only increases the number of photons, not the wavelength or freq...
- Thu Oct 15, 2020 1:28 pm
- Forum: Properties of Light
- Topic: Light Intensity
- Replies: 8
- Views: 179
Re: Light Intensity
I think that increasing the light intensity just means that you're increasing the number of photons.
- Thu Oct 15, 2020 1:14 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Difference regarding atomic spectroscopy and molecular spectroscopy
- Replies: 3
- Views: 272
Re: Difference regarding atomic spectroscopy and molecular spectroscopy
Atomic spectra are the transitions of electrons between electronic energy levels in isolated atoms. They are affected by interactions of the transitioning electrons with the nuclei spins and with the other electrons in the atom. Molecular spectra involve transitions in molecules with two or more ato...
- Wed Oct 07, 2020 11:21 am
- Forum: Limiting Reactant Calculations
- Topic: Discussion worksheet question
- Replies: 3
- Views: 166
Re: Discussion worksheet question
Also, the first thing you would need to do for this problem is balance the reaction. For more help, I'd suggest watching today's lecture on how to solve a stoichiometry problem.
- Wed Oct 07, 2020 11:19 am
- Forum: Limiting Reactant Calculations
- Topic: Discussion worksheet question
- Replies: 3
- Views: 166
Re: Discussion worksheet question
The percent yield is the actual yield divided by the theoretical yield multiplied by 100%. So, if the percent yield is 100%, then that means the actual yield divided by the theoretical yield is equal to one. This means the actual yield is equal to the theoretical yield. So, you'd find the theoretica...
- Wed Oct 07, 2020 11:14 am
- Forum: Significant Figures
- Topic: How man Sig Figs to use in the Textbook Problems
- Replies: 7
- Views: 182
Re: How man Sig Figs to use in the Textbook Problems
When you multiply or divide several numbers, or when you take roots, the number of significant figures in the answer should match the number of significant figures of the least precisely known number used in the calculation. For example, in 3.73×5.7=21, 3.73 has three significant figures and 5.7 has...