Search found 55 matches
- Sat Dec 07, 2019 2:58 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: polydentate
- Replies: 3
- Views: 294
Re: polydentate
it all depends on the structure of each molecule. like some have multiple potential bonding sites, but the sites aren’t far enough apart that 2 could bind, and some have 2 bonding sites that are far enough apart that it could bind to 2 molecules at the same time.
- Sat Dec 07, 2019 2:26 pm
- Forum: SI Units, Unit Conversions
- Topic: Test 2 Constants/Equations ERRORS
- Replies: 2
- Views: 307
Re: Test 2 Constants/Equations ERRORS
I know, hopefully!!
Another error: Ek = mv^2 intead of (1/2) mv^2
Another error: Ek = mv^2 intead of (1/2) mv^2
- Sat Dec 07, 2019 1:54 pm
- Forum: SI Units, Unit Conversions
- Topic: Test 2 Constants/Equations ERRORS
- Replies: 2
- Views: 307
Test 2 Constants/Equations ERRORS
Did anyone else notice that the constants sheet we were given for Test 2 was missing equations and had some inaccuracies? Like it says that ΔpΔx≥π instead of (h/4π), and didn't even have the second half of the equations for λ= , En = -, and En = . Was this intentional/did this happen with anyone els...
- Wed Dec 04, 2019 9:37 pm
- Forum: Amphoteric Compounds
- Topic: Selecting Which Acid/Base to React Test Oxide With
- Replies: 1
- Views: 280
Selecting Which Acid/Base to React Test Oxide With
What strategies can you use to figure out which acids/bases are good for reacting with the tested oxide? I understand that you should try to use the oxide in a reaction as both an acid and a base, but how do you figure out which substances to react the oxide with in the first place?
- Wed Dec 04, 2019 9:26 pm
- Forum: Amphoteric Compounds
- Topic: 6A.17
- Replies: 5
- Views: 473
Re: 6A.17
saigorijavolu33J wrote:Amphoteric compounds are compounds that can react as an acid and base. If you react them with water, there would be 2 reactions. If you write this out then you can tell. Also it is general pattern. There is chart in the textbook which can help.
Where is this chart in the textbook???
- Wed Dec 04, 2019 7:51 pm
- Forum: Balancing Chemical Reactions
- Topic: Delta Over Reaction Arrow
- Replies: 2
- Views: 1153
Delta Over Reaction Arrow
What does it mean when there's a delta symbol over the arrow in a chemical equation? As seen in problem 6A.7 b)
- Tue Dec 03, 2019 9:52 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: J.23
- Replies: 2
- Views: 189
J.23
The answers to parts a) and b) are H2CO3 (carbonic acid) and H2SO4 (sulfuric acid), respectively. Are we just supposed to know beforehand that carbonic acids and sulfuric acids are common/good ones to know? Are we supposed to memorize acids like these? Or are there strategies you could use to figure...
- Tue Dec 03, 2019 9:41 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: J.17
- Replies: 4
- Views: 397
J.17
What strategies can you use to figure out which part of the given salt is the anion/cation you're dealing with? How are you supposed to know that without looking it up?
- Sat Nov 30, 2019 1:50 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Ka constant
- Replies: 5
- Views: 437
Re: Ka constant
Ka is the equilibrium constant for a weak acid
- Sat Nov 30, 2019 1:37 pm
- Forum: Naming
- Topic: Common Names
- Replies: 2
- Views: 244
Re: Common Names
I would say don't stress yourself out about exceptions unless they are exceptions he specifically named in class.
- Sat Nov 30, 2019 1:36 pm
- Forum: Naming
- Topic: ethelynediaminetetraaceto
- Replies: 2
- Views: 264
Re: ethelynediaminetetraaceto
I agree, Google is very helpful! That exact coordination compound is also an example in the resource linked below. You could simply count the atoms (although the image given here doesn't seem to include the carbons or hydrogens). https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/Nami...
- Sat Nov 30, 2019 1:28 pm
- Forum: Naming
- Topic: Ligand Order
- Replies: 5
- Views: 383
Re: Ligand Order
In lecture Lavelle said that the order is: "(Greek prefix)" + "ligand names in alphabetical order" + "transition metal cation name" + "Roman numeral"
If there are anions, it goes: "anion name" + "(Greek prefix)" + "hydrate"
If there are anions, it goes: "anion name" + "(Greek prefix)" + "hydrate"
- Sat Nov 30, 2019 1:24 pm
- Forum: Naming
- Topic: Meaning of Cis and Trans
- Replies: 11
- Views: 960
Re: Meaning of Cis and Trans
This is a generalization, but many examples we are given include more than one atom of the same type. Adding onto everyone's answers above, oftentimes the same atom (which therefore has the same electronegativity) can be a good distinguisher of cis- vs. trans-. If the same atom types are on the same...
- Sun Nov 24, 2019 10:49 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle of bent
- Replies: 17
- Views: 1414
Re: Bond Angle of bent
Always start by thinking of the entire electron configuration first! Much easier than memorizing different VSEPR combinations.
- Sun Nov 24, 2019 10:45 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs linear
- Replies: 56
- Views: 4487
Re: Bent vs linear
It's helpful to think about how many electron pairs are occupying spots where there may/may not be atoms. Add the Xs and Es together to get the electron configuration, and then subtract as many atoms as there are lone pairs. This way you'll see which molecules should be "bent" down or not.
- Sun Nov 24, 2019 10:43 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Why is CH2Cl2 polar?
- Replies: 12
- Views: 813
Re: Why is CH2Cl2 polar?
I always find it's easier to think about it visually! I would recommend drawing the Lewis structures, and more importantly the molecular structures, and drawing arrows toward the molecules with more negative charge. Think about the trajectories of the arrows you're drawing!
- Fri Nov 22, 2019 10:50 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Removing Non-Axis Atoms First
- Replies: 4
- Views: 413
Removing Non-Axis Atoms First
Can someone remind me why we remove the atoms that are NOT on the axis first in order to determine molecular shape?
- Tue Nov 19, 2019 2:22 pm
- Forum: Hybridization
- Topic: Sigma and Pi Bond Practice Problems
- Replies: 1
- Views: 277
Sigma and Pi Bond Practice Problems
Does anyone know off-hand which problems from 2F are good for practicing just sigma and pi problems for Test 2?
- Sun Nov 17, 2019 8:04 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 3
- Views: 304
Re: Hybridization
I think hybridization notation is used to describe how many orbitals of each orbital level/type are occupied by electrons when they're not full?
- Sun Nov 17, 2019 8:01 pm
- Forum: Hybridization
- Topic: Test 2 Topics
- Replies: 11
- Views: 764
Re: Test 2 Topics
@DHavo_3H I think it has something to do with it being the most stable organization that requires the least amount of energy.
- Sun Nov 17, 2019 7:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Purpose of electron geometry
- Replies: 2
- Views: 273
Re: Purpose of electron geometry
Also electron geometry gives you a hint as to whether certain angles are larger/smaller than expected. If there are more lone pairs, they will have more "push" so the angles will likely be smaller than expected.
- Sun Nov 17, 2019 7:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR
- Replies: 5
- Views: 317
Re: VSEPR
Use the VSEPR formula to determine the number of atoms and lone pairs in a molecule. Add up the Xs and the Es to determine the structure of the electrons (e.g. tetrahedral, octahedral, etc.), then remove as many atoms as there are Es to find the actual molecular shape. For example, tetrahedral molec...
- Sun Nov 17, 2019 7:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Linear molecule with lone pairs
- Replies: 3
- Views: 279
Re: Linear molecule with lone pairs
As Lavelle stated in lecture, although only atom positions are used to name molecular shapes (e.g. linear), lone pairs still influence the molecular shape. Two examples of lone pairs in linear molecules are the trigonal bipyramidal structure with 3 lone pairs, and the octohedral structure with 4 lon...
- Sun Nov 10, 2019 1:47 pm
- Forum: Bond Lengths & Energies
- Topic: how to determine the energy of a bond
- Replies: 6
- Views: 603
Re: how to determine the energy of a bond
The formal energy is the difference between the number of valence electrons an atom normally has, and how many it has in a particular molecule. You can just count each dot individually, and then count only one electron for each bond (line).
- Fri Nov 08, 2019 11:57 pm
- Forum: Resonance Structures
- Topic: resonance hybrid
- Replies: 6
- Views: 386
Re: resonance hybrid
I think we have to know how to draw and name the different orbitals in the same layout as the "building up" method.
- Fri Nov 08, 2019 11:56 pm
- Forum: Resonance Structures
- Topic: resonance importance?
- Replies: 7
- Views: 472
Re: resonance importance?
It's also important to know that electrons don't "jump" from one resonance structure to the other, but rather the different resonance structures show the different placements of electrons as they constantly move about.
- Mon Nov 04, 2019 9:28 pm
- Forum: SI Units, Unit Conversions
- Topic: Unit Conversion
- Replies: 2
- Views: 272
Unit Conversion
Does anyone know if we have to include the nano/giga/mega/etc. prefixes in our answers? Or can we just use the basic unit and multiply it by 10^n in our final answer?
- Sun Nov 03, 2019 7:53 pm
- Forum: Ionic & Covalent Bonds
- Topic: Carbon Bonding
- Replies: 5
- Views: 151
Carbon Bonding
Does carbon prefer to gain or lose 4 electrons in order to form a full shell? Or is it equally as favorable?
- Sun Nov 03, 2019 7:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: In what order do electrons get removed?
- Replies: 7
- Views: 35870
Re: In what order do electrons get removed?
How about when it comes to f-orbitals? Problem 2A.5 b) is making me think that having both a half-full/full d-subshell and a full s-subshell is more important than a full f-subshell.
So then is the order of removal for the electrons in the lower periods: p<f<s<d ??
So then is the order of removal for the electrons in the lower periods: p<f<s<d ??
- Thu Oct 31, 2019 12:45 am
- Forum: Ionic & Covalent Bonds
- Topic: Valence Electrons?
- Replies: 15
- Views: 1081
Re: Valence Electrons?
Count from the last full period on the periodic table, representing a full electron shell, and that's how many valence electrons there are!
- Thu Oct 31, 2019 12:41 am
- Forum: Ionic & Covalent Bonds
- Topic: Polarity
- Replies: 6
- Views: 295
Re: Polarity
Depends on the specific molecule and how much "pull" each element has in it.
- Thu Oct 31, 2019 12:38 am
- Forum: Ionic & Covalent Bonds
- Topic: Midterm
- Replies: 10
- Views: 591
Re: Midterm
And bring a pen and a basic calculator! Professor Lavelle said that anything "over $10" is probably not allowed.
- Thu Oct 31, 2019 12:29 am
- Forum: Ionic & Covalent Bonds
- Topic: Homework for Week 5
- Replies: 8
- Views: 362
Re: Homework for Week 5
It might be useful to do the most up-to-date problems if you're all caught up on the lectures, but I always just do whatever sections I need to focus more on! Just make sure to pace yourself and actually cover every topic :)
- Thu Oct 31, 2019 12:24 am
- Forum: Ionic & Covalent Bonds
- Topic: Ionic and Covalent Bonds
- Replies: 6
- Views: 246
Re: Ionic and Covalent Bonds
A coordinate covalent bond is a covalent bond in which one atom provides both electrons in a pair to another atom.
- Wed Oct 23, 2019 10:02 pm
- Forum: Trends in The Periodic Table
- Topic: Location of elements
- Replies: 12
- Views: 756
Re: Location of elements
It would be helpful! In general, metals are the majority of the table on the left side, nonmetals are the upper-right corner, and metalloids sort of form a staircase in between metals and nonmetals.
- Wed Oct 23, 2019 10:00 pm
- Forum: Trends in The Periodic Table
- Topic: Shielding
- Replies: 8
- Views: 603
Re: Shielding
Everyone above explained the concept that electrons closer to the nucleus have a stronger pull towards it than the further valence electrons nicely. The important thing to take away is that electrons in further shells are more easy to form bonds with other atoms because there's less pull!
- Wed Oct 23, 2019 9:58 pm
- Forum: Trends in The Periodic Table
- Topic: bond length
- Replies: 9
- Views: 476
Re: bond length
I'm not sure I think he said that that's assessed in a formal lab setting? I think talking about the specifics of bond length was more to emphasize that electrons are not bouncing between elements, forming only a few specific double bonds. Electrons are always moving! Can someone elaborate on this? ...
- Wed Oct 23, 2019 9:56 pm
- Forum: Trends in The Periodic Table
- Topic: Electron affinity
- Replies: 5
- Views: 286
Re: Electron affinity
Elements on both sides of the periodic table are essentially trying to get "closer to" a noble gas in terms of stability in its electrons. Because elements on the left side want to lose electrons in order to be more stable, they would have less of an affinity, or attraction to, other elect...
- Wed Oct 23, 2019 9:54 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions
- Replies: 3
- Views: 254
Re: Exceptions
It's also interesting to note that elements with low ionization energies typically form cations, which are typically metals. Because metals are grouped on the left side of the periodic table, you can use this as a memory clue to remind you that the ionization energy increases as you move across a pe...
- Sun Oct 20, 2019 5:55 pm
- Forum: Properties of Electrons
- Topic: 1B. 15C [ENDORSED]
- Replies: 4
- Views: 285
Re: 1B. 15C [ENDORSED]
To respond to DHavo^^, I thought that you could use the two equations in similar ways because you can isolate and substitute v in both?
- Sun Oct 20, 2019 5:50 pm
- Forum: Properties of Electrons
- Topic: Energy increasing
- Replies: 7
- Views: 521
Re: Energy increasing
I thought that the energy levels decreased as you moved further away from the nucleus because there was less electrostatic attraction?
- Sun Oct 20, 2019 5:46 pm
- Forum: Properties of Electrons
- Topic: Electron structures
- Replies: 4
- Views: 359
Re: Electron structures
Each orbital can hold a maximum of 2 electrons, and the two electrons in the same orbital have opposite spins.
- Sun Oct 20, 2019 5:44 pm
- Forum: Properties of Electrons
- Topic: d vs s orbitals
- Replies: 6
- Views: 247
Re: d vs s orbitals
The reasoning behind the order is that you're supposed to write it in order of lowest energy to highest energy. Because shells that are further away from the nucleus have less electrostatic attraction, further shells have less energy (double-check me on this?).
- Sun Oct 20, 2019 5:41 pm
- Forum: Properties of Electrons
- Topic: Quantum numbers
- Replies: 4
- Views: 238
Re: Quantum numbers
To add onto Cassidy's comment above, it's important to know that although each orbital can hold a maximum of 2 electrons, each energy shell can have more than 2 (aside from s) because there are multiple orbitals in each shell.
- Sun Oct 13, 2019 3:12 pm
- Forum: Properties of Electrons
- Topic: Electron Energy Levels
- Replies: 8
- Views: 357
Re: Electron Energy Levels
Does the number of energy levels not depend on the number of electrons the atom has? Or was that a simpler way of thinking about it in high school?
- Fri Oct 11, 2019 1:51 pm
- Forum: Student Social/Study Group
- Topic: Final Jitters
- Replies: 457
- Views: 473859
Re: Final Jitters
Definitely get a lot of sleep! If you are staying up late studying, you are losing sleep and are most likely not really taking in all the information in the later hours anyways. Also remember to sit back and take a deep breath any time you're feeling overwhelmed. Also, most importantly, put it all i...
- Fri Oct 11, 2019 1:46 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Photoelectric Effect
- Replies: 4
- Views: 232
Re: Photoelectric Effect
In response to Brooke above, I think he clarified that it's more about the frequency than the amplitude, as you have to think of each atom separately (like the water flowing example).
- Fri Oct 11, 2019 1:45 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9836
Re: Rydberg equation [ENDORSED]
Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else?
- Fri Oct 11, 2019 1:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 491711
Re: Advice from a Medical Student [ENDORSED]
Thank you for the advice Ashley! How much do you think you specifically reference this information from this class in your work today, and as a medical student?
- Fri Oct 11, 2019 1:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 2 Homework Problems [ENDORSED]
- Replies: 67
- Views: 9055
Re: Week 2 Homework Problems [ENDORSED]
You can do problems from the Review sections, as that is the majority of the content for this week's Test.
- Thu Oct 03, 2019 12:04 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Empirical and Molecular Formulas
- Replies: 13
- Views: 668
Re: Empirical and Molecular Formulas
In the simplest terms, the empirical formula is the relative number of atoms, while the molecular formula is the actual number of atoms.
- Thu Oct 03, 2019 12:01 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Units in Answer
- Replies: 18
- Views: 881
Re: Units in Answer
Like what many people said above, it depends what the problem is asking for. If the problem was asking you to solve for the mass, the answer would be in grams. I believe in lecture today he said that the SI fundamental units were:
- mass = kilograms
- length = meters
- time = seconds
- mass = kilograms
- length = meters
- time = seconds
- Wed Oct 02, 2019 11:58 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Balancing Equations [ENDORSED]
- Replies: 25
- Views: 2133
Re: Balancing Equations [ENDORSED]
That was definitely a technique he used for that specific problem! Working with stoichiometry problems will never have the same set of moves for each problem. In this case, we had a coefficient with a denominator of 2, so we had to multiply the entire problem by 2 in order to get rid of the fraction...
- Wed Oct 02, 2019 11:55 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: E1
- Replies: 13
- Views: 3153
Re: E1
Responding to Brenna: The question is essentially telling us that we're lining up Ag atoms in a single-file line. You don't have to "convert" the problem to atoms because it is telling you that the unit we're working with is atoms right from the start.
- Wed Oct 02, 2019 11:47 pm
- Forum: SI Units, Unit Conversions
- Topic: Can someone tell me where I can access the Solutions Manual?
- Replies: 6
- Views: 456
Re: Can someone tell me where I can access the Solutions Manual?
As someone mentioned above, the textbook offers solutions to both the self-tests in the readings and the odd-numbered exercise problems. According to the table of contents, both of them should be in the section at the end of the book with page numbers starting with "C."