Search found 53 matches
- Fri Dec 11, 2020 4:50 pm
- Forum: Naming
- Topic: "ate" and "ic"
- Replies: 4
- Views: 583
Re: "ate" and "ic"
Lavelle mentioned in his lecture that you use "-ate" with the metal name when the complex has a negative charge. So for example: [Ni(CN)4)] 2- : the name would be tetra cyano nickelATE (II)
- Fri Dec 11, 2020 4:47 pm
- Forum: Student Social/Study Group
- Topic: Final
- Replies: 18
- Views: 786
Re: Final
Dr. Lavelle has mentioned that he would use textbook problems but with different numbers, so I suggest practicing those.
- Fri Dec 11, 2020 4:23 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating Ligands
- Replies: 2
- Views: 204
Re: Chelating Ligands
I don't think so-- they won't be able to bind the same atom because the atoms are on opposite sides.
- Fri Dec 11, 2020 4:09 pm
- Forum: Air Pollution & Acid Rain
- Topic: pH of hard water
- Replies: 4
- Views: 300
Re: pH of hard water
I think hard water is usually alkaline-- do you remember where did Dr. Lavelle mentioned it was acidic? I forgot.
- Fri Dec 11, 2020 4:07 pm
- Forum: Hybridization
- Topic: When is Hybridization used?
- Replies: 2
- Views: 247
Re: When is Hybridization used?
Hi! if you need any more confirmation, I found this website pretty helpful: https://socratic.org/questions/how-to-t ... -hybridize
- Fri Dec 11, 2020 4:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grading scale
- Replies: 29
- Views: 2737
Re: Grading scale
I think Dr. Lavelle hasn't determined the grading scale yet? Only that like a 250/500 is like a C- or C+ for now, but I'm not entirely sure.
- Fri Dec 11, 2020 4:04 pm
- Forum: Industrial Examples
- Topic: Chemotherapy
- Replies: 22
- Views: 1494
Re: Chemotherapy
I only remember Dr. Lavelle going over Cisplatin-- do we have to know others?
- Fri Dec 11, 2020 2:35 pm
- Forum: Electronegativity
- Topic: help with a periodic trend problem?
- Replies: 4
- Views: 463
Re: help with a periodic trend problem?
Does this question have to do with the highly polarizable e-? Like, highly polarizable e- makes the molecule have a more covalent character? (Or am I getting this wrong)
- Fri Dec 11, 2020 2:20 pm
- Forum: Student Social/Study Group
- Topic: Anxiety
- Replies: 109
- Views: 6695
Re: Anxiety
Study for a bit, then take a short break (repeat)! I have bad habits with last minute cramming, but it honestly just gives me more anxiety. I've been trying to go exercise more, since it takes my mind off studying for a bit.
- Fri Dec 11, 2020 2:18 pm
- Forum: Naming
- Topic: Adding 'ion' to the name
- Replies: 2
- Views: 168
Re: Adding 'ion' to the name
If it has a charge, I think it's a pretty good chance that it's an ion, so we add it the name.
- Sun Nov 29, 2020 7:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: H20 Shape
- Replies: 17
- Views: 946
Re: H20 Shape
Simply put, H2O has a lone pair of electrons are on the same side of the molecule, resulting in repulsion. This repulsion of the lone pairs of electrons on the oxygen atom causes the bond of the hydrogen to the oxygen to be pushed “downwards.”
- Sun Nov 29, 2020 7:09 pm
- Forum: Student Social/Study Group
- Topic: Tips for Staying Focused
- Replies: 64
- Views: 3489
Re: Tips for Staying Focused
I’m so bad with distractions, so I started turning off all my notifications/turning my phone on DND. Also, studying for an hour then taking a ten minute break also helps really well instead of completely cramming.
- Sun Nov 29, 2020 7:07 pm
- Forum: Student Social/Study Group
- Topic: Studying for Final Exam
- Replies: 57
- Views: 2366
Re: Studying for Final Exam
Redoing book problems! Also maybe doing some of the UA worksheets, since everyone also really likes those problems as well.
- Sun Nov 29, 2020 7:04 pm
- Forum: Electronegativity
- Topic: Sapling Week 8 Polarity
- Replies: 5
- Views: 359
Re: Sapling Week 8 Polarity
I kind of had the same thought, but I suppose having polar bonds is correlated with the overall molecule also being polar? Does this mean molecules with polar bonds will always (or more often) be considered as polar overall?
- Tue Nov 24, 2020 11:55 pm
- Forum: Empirical & Molecular Formulas
- Topic: Molecular Formula and Empirical Formula Mass
- Replies: 6
- Views: 503
Re: Molecular Formula and Empirical Formula Mass
I think the empirical formula is the lowest whole ratio of atoms possible! A molecular formula shouldn't be smaller than the empirical formula, and I don't think non-whole numbers are preferred either (:
- Tue Nov 24, 2020 10:33 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 9
- Views: 502
Re: Resonance
Resonance occurs when a molecules cannot be expressed by a single lewis structure. You will know if a molecule has resonance structures if it has a lone pair or a double bond on the atom next to a double bond.
- Tue Nov 24, 2020 10:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: More Covalent
- Replies: 8
- Views: 433
Re: More Covalent
The strength of a covalent bond increases as the number of bonds increase (i.e: in order of decreasing to increasing strength: single bond < double bond < triple bond). If the molecules you're comparing both have the same amount of bonds, you'd refer to the size of the molecule, so the larger the at...
- Tue Nov 24, 2020 10:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: More Covalent
- Replies: 8
- Views: 433
Re: More Covalent
The strength of a covalent bond increases as the number of bonds increase (i.e: in order of decreasing to increasing strength: single bond < double bond < triple bond). If the molecules you're comparing both have the same amount of bonds, you'd refer to the size of the molecule, so the larger the at...
- Tue Nov 24, 2020 10:25 pm
- Forum: Octet Exceptions
- Topic: Octet Exceptions
- Replies: 11
- Views: 993
Re: Octet Exceptions
In Lavelle's lectures, he talked about radicals (compounds w/ unpaired e-) and lewis acids/bases that were exceptions to the octet guideline (lecture 15). with Lewis/base reactions, a coordinate covalent bond will form when another atom provides both e- to the lewis acid molecule.
- Tue Nov 24, 2020 10:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Differentiating Between Ionic and Covalent
- Replies: 3
- Views: 211
Re: Differentiating Between Ionic and Covalent
In general, nonmetals will form covalent bonds with nonmetals, and metals will form ionic bonds with nonmetals.
- Wed Nov 18, 2020 9:35 pm
- Forum: Lewis Structures
- Topic: line structures of organic compounds
- Replies: 1
- Views: 104
Re: line structures of organic compounds
I just saw this as well-- and I don't think we have to know it? I'm not completely sure though-- I don't remember it being in lectures either.
- Wed Nov 18, 2020 9:31 pm
- Forum: Bond Lengths & Energies
- Topic: Comparing Strengths of Interactions Between Ions
- Replies: 2
- Views: 209
Re: Comparing Strengths of Interactions Between Ions
Hi, When solving this problem, I would first look at the size/charge of the cation and anion respectively. A smaller sized cation with a greater positive charge will lead to stronger ionic character, thus making the answer to this question CAO rather than KCL. This was actually super helpful-- than...
- Wed Nov 18, 2020 9:13 pm
- Forum: Dipole Moments
- Topic: Dipole Dipole Interactions
- Replies: 7
- Views: 410
Re: Dipole Dipole Interactions
I thought of the nonpolar molecules as the ones consisting of non-metal atoms (which therefore, yes, Br2, H2, F2 would be nonpolar). I never really thought about the small electronegativity differences and if that factored in as well. Hopefully someone answers this :')
- Wed Nov 18, 2020 9:08 pm
- Forum: Dipole Moments
- Topic: Dipole vs Polar molecule
- Replies: 2
- Views: 135
Re: Dipole vs Polar molecule
I think they're interchangeable-- a dipole is a result of a polar molecule with polar bonds I believe? I may be wrong.
- Fri Nov 13, 2020 11:24 pm
- Forum: Bond Lengths & Energies
- Topic: Covalent Bond Length
- Replies: 13
- Views: 1309
Re: Covalent Bond Length
I'm not sure about others, but I believe bond length is determined by the # of bonded electrons? So the higher the bond order, the stronger the pull and the shorter the bond length. So bond length increases from triple bond < double bond < single bond
- Fri Nov 13, 2020 11:19 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: is it polar
- Replies: 6
- Views: 476
Re: is it polar
Hi! We can tell if a molecule is polar if one atom is more electronegative than the other. A simple example is H2O, where Oxygen has a partial negative charge and the Hydrogens have partial positive charges. This website helps a lot with explaining assigning charges for dipole moments as well (: htt...
- Fri Nov 13, 2020 11:16 pm
- Forum: Dipole Moments
- Topic: Interaction potential energy
- Replies: 2
- Views: 110
Re: Interaction potential energy
I think it's because energy always needs to be put into a system in order for like charges to be brought closer together.
- Fri Nov 13, 2020 11:07 pm
- Forum: Resonance Structures
- Topic: Resonance hybrid of molecules
- Replies: 2
- Views: 114
Re: Resonance hybrid of molecules
A resonance hybrid is a combination of all possible resonance structures (and resonance structures exist when a single Lewis structure cannot full describe a molecules binding). A molecule can have resonance when it has a lone pair or a double bond on the atom next to a double bond, and the overall ...
- Sun Nov 08, 2020 11:53 pm
- Forum: Octet Exceptions
- Topic: specific exceptions
- Replies: 3
- Views: 124
Re: specific exceptions
I think we'll be able to tell if we do the configurations and doing configurations might be a good way to double check! I'm not sure if there's any we need to know off the top of our heads
- Sun Nov 08, 2020 11:49 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Importance of anions and cations
- Replies: 15
- Views: 1029
Re: Importance of anions and cations
An easy way to remember is ca(+)ion is positive and anion is the opposite (:
- Sun Nov 08, 2020 11:47 pm
- Forum: Lewis Structures
- Topic: Sapling Homework 7
- Replies: 3
- Views: 67
Re: Sapling Homework 7
A Lewis base is any species that can donate a pair of electrons, and a Lewis acid is any species that can accept a pair of electrons. So atoms, ions, or molecules with a lone-pair of electrons can be a Lewis base I believe. Please correct me if I'm wrong!
- Sun Nov 08, 2020 11:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: Oxidation number
- Replies: 7
- Views: 178
Re: Oxidation number
This website provides some practice problems too after some explanations (: hopefully this helps!
http://chemed.chem.purdue.edu/genchem/t ... xnumb.html
http://chemed.chem.purdue.edu/genchem/t ... xnumb.html
- Sun Nov 01, 2020 1:13 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Unusual Electron Configuration
- Replies: 3
- Views: 677
Re: Unusual Electron Configuration
There was a similar question posted about this, and someone explained that (in, for example Ag) the 5s orbital will get filled prior to the 4d orbital, but in some cases the 4d orbital is more stable w/ 10 e- instead of 9, so it may take an electron from the 5s orbital. Hopefully this makes sense, a...
- Sun Nov 01, 2020 1:10 am
- Forum: Properties of Light
- Topic: Is c always the speed of light?
- Replies: 92
- Views: 4740
Re: Is c always the speed of light?
All we need to know for this class is that c=speed of light= 3.0x10^8
- Sun Nov 01, 2020 1:01 am
- Forum: Properties of Light
- Topic: Midterm
- Replies: 6
- Views: 295
Re: Midterm
I think one of the UA's mentioned that Lavelle doesn't really curve his exams, but I'm not sure about this one. He mentioned partial credit, but it's also unsure about how they're going to be given (if they will be) because of the exam being MC.
- Sun Nov 01, 2020 12:59 am
- Forum: Trends in The Periodic Table
- Topic: Sapling HW #30
- Replies: 6
- Views: 273
Re: Sapling HW #30
Simply put, I like to think of it as Rb- gaining an e- so it's negative, and if it gains an e- then the radius will be larger. Rb+ lost an electron and is positive, so the radius will be smaller.
- Sun Nov 01, 2020 12:58 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals and Electrons
- Replies: 9
- Views: 260
Re: Orbitals and Electrons
The Pauli Exclusion Principle-- there are only two possible spins, so only 2 electrons can be in an orbital
- Sun Oct 25, 2020 10:55 am
- Forum: Properties of Electrons
- Topic: Number of Questions of Midterm 1
- Replies: 8
- Views: 261
Re: Number of Questions of Midterm 1
I think someone said they weren't too sure because it's up to Lavelle, but there shouldn't be too many questions because of the time limit and some questions will be longer than others.
- Sun Oct 25, 2020 10:46 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: P-, d-, f- Orbitals
- Replies: 5
- Views: 285
Re: P-, d-, f- Orbitals
The wave function Ψ^2 represents the probability of finding electron density. So in p-, d-, and f- orbitals, there's places in the orbital where there's 0 probability of having electron density. If you watch his lecture again and look at the diagrams he showed, you can see areas on the orbitals wher...
- Sun Oct 25, 2020 10:32 am
- Forum: Photoelectric Effect
- Topic: unit conversion hw Q 1.3
- Replies: 7
- Views: 812
Re: unit conversion hw Q 1.3
Convert the units before computing the equation. You'll know when to convert if the constant units you're using in the equation are set, and the given numbers in the problem are different. ie: speed: m.s-1, wavelength given in problem: nm
- Sun Oct 25, 2020 10:22 am
- Forum: Properties of Electrons
- Topic: intensity vs energy
- Replies: 29
- Views: 3108
Re: intensity vs energy
An increase in intensity is an increase in particles, while an increase in energy is an increase in frequency. Think of it as more intense = throwing more balls at a target.
- Sat Oct 17, 2020 9:26 am
- Forum: Electronegativity
- Topic: periodic table
- Replies: 16
- Views: 685
Re: periodic table
electronegativity: increases from left to right across a period of elements. decreases from top to bottom down a group. ionization energy: increases from left to right. electron affinity: increases from left to right. generally decreases down a group of elements atomic radius: increases down a group...
- Sat Oct 17, 2020 9:13 am
- Forum: Significant Figures
- Topic: Sig Figs and Constants on Exams
- Replies: 9
- Views: 477
Re: Sig Figs and Constants on Exams
You should probably use the full length of the constants listed, but use the correct sigfigs depending on the rest of the problem, just to make sure that your answer is closer to what Dr. Lavelle has as the answer.
- Fri Oct 16, 2020 1:00 pm
- Forum: Properties of Electrons
- Topic: Electrons Excited or Ejected
- Replies: 19
- Views: 782
Re: Electrons Excited or Ejected
Electrons are excited by the photoelectric effect--the energy supplied exceeds the work function then the electron is ejected with KE = hf - phi. Otherwise, it goes to a higher orbital and then falls to a lower orbital, which releases energy. Ejection only occurs when the work function is exceeded I...
- Fri Oct 16, 2020 12:43 pm
- Forum: Properties of Light
- Topic: bohr frequency condition
- Replies: 4
- Views: 230
Re: bohr frequency condition
Bohr's frequency condition is ΔE=hv, meaning the difference in energy (when a high energy e- drops to a lower energy e- level) is equal to Planck's constant x frequency. (lmk if this is wrong! I'm not completely sure myself)
- Fri Oct 16, 2020 12:29 pm
- Forum: Properties of Electrons
- Topic: Bound vs. Free Electrons
- Replies: 6
- Views: 340
Re: Bound vs. Free Electrons
I think free electrons are at a higher energy state than bound electrons are? free electrons aren't bounded to atoms, whereas bounded electrons are bounded to the nucleus I believe (please correct me if I'm wrong!)
- Wed Oct 07, 2020 1:20 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Sapling Week 1 HW_problem #7
- Replies: 5
- Views: 160
Re: Sapling Week 1 HW_problem #7
Yes, this is how I did the problem as well!
- Wed Oct 07, 2020 1:15 pm
- Forum: Limiting Reactant Calculations
- Topic: Sapling Question #10
- Replies: 9
- Views: 322
Re: Sapling Question #10
I ended up with the same answer but never got 72.1 g/mol for 2 butanone and am not sure where everyone is getting that calculation? Is that just from getting the molecular formula and then determining the molar mass? I actually just googled the molar mass of butanone :') I'm not sure if we were sup...
- Tue Oct 06, 2020 11:55 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: #25 on Molarity and Dilution of a Solution Post Assessment
- Replies: 6
- Views: 274
Re: #25 on Molarity and Dilution of a Solution Post Assessment
I did this post assessment module a few days ago but if I remember correctly I got it right using these steps: Convert the 5.00 g KMnO4 to mols using its molar mass (158.04g/mol) and you'll get 0.0316 mol. Then using the volume you're given, find the molarity of the solution. Make sure to change th...
- Tue Oct 06, 2020 11:46 pm
- Forum: Limiting Reactant Calculations
- Topic: Sapling Question #10
- Replies: 9
- Views: 322
Re: Sapling Question #10
I ended up with the same answer but never got 72.1 g/mol for 2 butanone and am not sure where everyone is getting that calculation? Is that just from getting the molecular formula and then determining the molar mass? I actually just googled the molar mass of butanone :') I'm not sure if we were sup...
- Tue Oct 06, 2020 11:41 pm
- Forum: Empirical & Molecular Formulas
- Topic: M19: oxygen
- Replies: 4
- Views: 121
Re: M19: oxygen
Is it perhaps because in the way you calculated the moles "2(0.0155) + 2(0.0097) = 0.0504 mol O?," the 2(0.0097) is just supposed to be (0.0097)? I think I understand that you multiplied the (0.0155) by 2 because there are 2 Oxygen atoms to one Carbon atom in CO2, but in H2O, there's 1 Oxy...
- Tue Oct 06, 2020 11:28 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: #25 on Molarity and Dilution of a Solution Post Assessment
- Replies: 6
- Views: 274
Re: #25 on Molarity and Dilution of a Solution Post Assessment
Step 1. Covert 5.00g KMnO4 to moles: 5.00g *(1mol/158.04g) = 0.0316 mol KMnO4 Step 2. Covert 150.00 mL to L: 0.150 L Step 3. Using the M1V1=M2V2 formula, the 20.00 ml (0.02L) will be your V1, the 250.00 ml (0.250 L) is V2 Step 4. M1 will be calculated from step 1 and 2: (0.0316 mol/0.150L) = 0.211M ...
- Mon Oct 05, 2020 4:01 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity Question
- Replies: 7
- Views: 396
Re: Molarity Question
Step 1. Covert 5.00g KMnO4 to moles: 5.00g *(1mol/158.04g) = 0.0316 mol KMnO4 Step 2. Covert 150.00 mL to L: 0.150 L Step 3. Using the M1V1=M2V2 formula, the 20.00 ml (0.02L) will be your V1, the 250.00 ml (0.250 L) is V2 Step 4. M1 will be calculated from step 1 and 2: (0.0316 mol/0.150L) = 0.211M ...