## Search found 87 matches

Sun Jan 24, 2021 8:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 2 #7
Replies: 8
Views: 41

### Re: Sapling Week 2 #7

Hello! The ice table considers that NaClO in water dissociates into Na+ and ClO-. Since Na+ cannot form a new compound NaOh in water (bc NaOH strong base, therefore it is considered a "spectator ion"), next we see ClO- ions in water. (ClO- aq). Since these equations are all balanced with o...
Sun Jan 24, 2021 8:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: derive pKW = pH + pOH [ENDORSED]
Replies: 3
Views: 18

### Re: derive pKW = pH + pOH[ENDORSED]

I would say you hit the nail right on the head; understand how pKa and pKb are derived, how you can observe the autoprotolysis of water, know that pH + pOH = 14, know the conditions of a solution when comparing pH to pKa/pKb, and be able to apply these in context when looking at acid/base dissociati...
Sun Jan 24, 2021 8:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Making the Approximating for X: K or % Ionization?
Replies: 6
Views: 20

### Making the Approximating for X: K or % Ionization?

I was wondering which is a more reliable indicator for maknig the approximation? There's a question on the Sapling homework where the K is very small (<10 to the -3) but the % ionization is greater than 5%. In a case like this, which indicator is better?
Sun Jan 24, 2021 7:47 pm
Forum: Phase Changes & Related Calculations
Topic: Steam
Replies: 25
Views: 78

### Re: Steam

I wanted to further this question; looking at the phase change diagram, we see that heat is continuously supplied during the "liquid vaporization" stage while the temperature remains the same, meaning that when the steam contacts the skin and begins to condense, not only is it at 100 degre...
Sun Jan 24, 2021 2:29 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH vs pKa in Equilibrium
Replies: 1
Views: 19

### pH vs pKa in Equilibrium

kind of an old content question but how can we determine whether a reaction favors reactants or products based on how the pH compares to the pKa/pKb when lokoing at acid/base dissociation?
Thu Jan 21, 2021 2:20 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How the pH changes in water with a stong acid or base (but mainly acid)
Replies: 3
Views: 16

### How the pH changes in water with a stong acid or base (but mainly acid)

In one of last week's lectures Dr. Lavelle mentions that adding a weak acid and calculating the concentration of H30+, the pH of a solution in water does not actually change that much. I was wondering about a similar concept reagrding strong acids and abses. Why is the concentration of H+, for examp...
Wed Jan 20, 2021 12:00 am
Forum: Ideal Gases
Topic: 5I.3
Replies: 4
Views: 28

### 5I.3

Would you use pv=nRT to solve this? You're not given a volume, so would we assume 1 L?
Sun Jan 17, 2021 3:39 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Box method
Replies: 5
Views: 30

### Re: ICE Box method

Hello, I am having a bit of difficulty understanding how to use the ice box and was wondering if someone could explain how I would use it in these chemical equilibrium problems? So an ice box is used for weak acids or bases that do not completely dissociate. There are three sections to consider: th...
Sun Jan 17, 2021 3:38 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Box method
Replies: 5
Views: 30

### Re: ICE Box method

Hi Bronson, I will try my best to help out here. I learned it as RICE (adding an R for the line with the reaction) but it's essentially the same concept. Remember generally using an ICE table you'll be using concentrations, so be sure you have values in M (mol/L) On the first line, you'll want to wr...
Sun Jan 17, 2021 3:29 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature
Replies: 45
Views: 126

### Re: Temperature

Why does temperature change K and not Q values? or does temperature alter the conditions of the reaction enough that K is different?

If the second is true, why would Q remain constant?
Sat Jan 16, 2021 11:17 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's with Solids
Replies: 5
Views: 17

### Le Chatelier's with Solids

If you have a reaction where a solid and gas react to make a gas, would increasing the amount of solid cause the reaction to favor the products? Or would there be no change?
Tue Jan 12, 2021 12:08 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Affect of Changing Pressure on K
Replies: 5
Views: 46

### Affect of Changing Pressure on K

I understand that adding an inert gas to alter pressure of a rxn of gases would not change Kc and therefore by Le Chatelier's the reaction would not change/respond. What about Kp though?
Tue Jan 12, 2021 12:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Unchanged K, Changed Pressure
Replies: 2
Views: 22

### Unchanged K, Changed Pressure

I understand that changing pressure does not change the equilibrium constant, but I just wanted to think about this conceptually: decreasing the volume increases pressure, which increases the reaction rate. So when we look at chemical reactions (here we have conditions iddeal for an increased amount...
Sun Jan 10, 2021 6:28 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Increasing the Yield of the Product.
Replies: 5
Views: 24

### Re: Increasing the Yield of the Product.

This (also) follows Le Cathelier's Principle, but basically if you reduce the amout of product currently available, the equilibrium will tend to make more since there is less available. I had an old teacher that thought of this as a seesaw: when in equilibrium, products and reactants are in line. If...
Sun Jan 10, 2021 6:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Dynamic
Replies: 4
Views: 32

### Re: Equilibrium Dynamic

Le Chatelier's Principle describes what changes dynamic equilibrium. Beyond temperature, pressure and concentration also affect the state of equilibrium! Here's a helpful link that describes this: https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_M...
Sun Jan 10, 2021 6:20 pm
Forum: Ideal Gases
Topic: Difference between real and ideal gas
Replies: 10
Views: 76

### Re: Difference between real and ideal gas

Although the last few posts appropriately described the difference between ideal gases and real gases, I wanted to bring up a really simple and useful way to quantify how "ideal" a gas really is -- its compressibility. The compression factor (Z) of a gas can be found by comparing the mola...
Sun Jan 10, 2021 6:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kc
Replies: 9
Views: 30

### Re: K vs Kc

Can you recall which section it came from? If I recall correctly, Kc refers to K when the reaction has molarities (typically aqueous reactants and products) when K is just generally referred to as the equilibrium constant. The textbook says (in 5H.3) "You are free to choose either K or KcKc to ...
Sun Jan 10, 2021 4:23 pm
Forum: Ideal Gases
Topic: Advice on how to navigate Chem Community
Replies: 17
Views: 74

### Re: Advice on how to navigate Chem Community

I'll second Jason here and say that the search function is also extraordinarily helpful in addition to the quick links and board index. Not only is it good for finding sapling questions, but it's also great for looking up specific content within the subtopics. Hope that (and the various other respon...
Sun Jan 10, 2021 3:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook problem 5G.5
Replies: 5
Views: 28

### Re: Textbook problem 5G.5

Just wanted to clarify that at equilibrium the concentrations/pressures are "unchanged" only because the forward and backwards reactions are happening at the same rate, not because the reaction is no longer happening.
Sat Dec 12, 2020 8:24 pm
Forum: Identifying Acidic & Basic Salts
Topic: Spectator ions
Replies: 2
Views: 19

### Re: Spectator ions

You can think of the results of dissolving strong acids in bases. Since strong acids and bases dissociate entirely, their resulting ions in solution wouldn't influence the pH since they won't re-bind to the original OH or H. Other examples could be Br- (from HBr) or K+ (from KOH).
Sat Dec 12, 2020 8:22 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: London Dispersion Force
Replies: 4
Views: 38

### Re: London Dispersion Force

What Hannah said-- the larger the surface area between two molecules, the greater opportunities to induce dipoles and have LDF interactions. This makes more sense for linear molecules. If you put two pencils together, they would touch at a greater surface area that if you put two ping pong balls tog...
Fri Dec 11, 2020 1:30 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Textbook Question 2A19)
Replies: 2
Views: 26

### Textbook Question 2A19)

Why does the Ni 2+ion have two unpaired electrons?
Thu Dec 10, 2020 10:51 pm
Forum: Identifying Acidic & Basic Salts
Topic: Acidic, basic, or neutral?
Replies: 8
Views: 84

### Re: Acidic, basic, or neutral?

In the lecture from Wed, Dr. Lavelle uses HCl + NH3 --> NH4Cl and explains that the ammonium cation makes the solution acidic. Why is that? Is it based on conjugates or does NH4 donate a proton in solution?
Thu Dec 10, 2020 12:25 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Determining Acidic Character: Oxoacids and Polarization?
Replies: 2
Views: 19

### Re: Determining Acidic Character: Oxoacids and Polarization?

(slightly related but in addition why isn't HF a strong acid?)
Thu Dec 10, 2020 12:25 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Determining Acidic Character: Oxoacids and Polarization?
Replies: 2
Views: 19

### Determining Acidic Character: Oxoacids and Polarization?

So on sapling question 11 for this week, the feedback I got after getting it wrong (LOL yall pray for me on this final) was that "stronger oxoacids contain more polarized O-H bonds. The more electronegative the central atom, the more polarized the O-H bond will be." I'm confused on how thi...
Wed Dec 09, 2020 7:33 pm
Forum: Ionic & Covalent Bonds
Topic: Clarifying Correct Covalent and Ionic bond Models [ENDORSED]
Replies: 1
Views: 31

### Clarifying Correct Covalent and Ionic bond Models[ENDORSED]

I undesrtand that part of correcting the covalent bond understand is knowing about dipole moments and polar covalent bonds, and fully understanding the ionic model takes into account size and sharing of electrons. Is there more to it that is fundamental to understanding the characteristics of both t...
Tue Dec 08, 2020 1:56 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Question from Monday's Lecture?
Replies: 1
Views: 19

### Question from Monday's Lecture?

Dr. Lavelle in the lecture said a solution is acidic if pH<pKa. Why is that?

Additionally, it was also mentioned that the organic acid HA in the example, when in acidic solution pH of 6, that the acid is protonated (with the H+). Why does this make the organic acid neutral?
Sun Dec 06, 2020 7:37 pm
Forum: Student Social/Study Group
Topic: chelating compounds- i just thought this was funny
Replies: 1
Views: 41

### chelating compounds- i just thought this was funny

from https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Modules_and_Websites_(Inorganic_Chemistry)/Coordination_Chemistry/Complex_Ion_Equilibria/Chelation "The term chelate was first applied in 1920 by Sir Gilbert T. Morgan and H.D.K. Drew [J. Chem. Soc., 1920, 117, 1456], who stated: ...
Sun Dec 06, 2020 7:11 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strengths of Acids: Polarity
Replies: 6
Views: 63

### Re: Strengths of Acids: Polarity

It's probably safe to assume that stronger acids have weaker and more polar hydrogen-X atom bonds because strong acids are more likely to give off their protons. Wouldn't higher polarity make it a theoretically stronger-weak acid? For example, HI has a more polar bond that HBr but since HBr is bigg...
Sat Dec 05, 2020 4:28 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Ligands
Replies: 3
Views: 28

### Re: Polydentate Ligands

Since a ligand bonds in a chelating complex by donating a lone pair, look for several atoms with one pairs within the same molecule; two lone pairs on the same atom can't bond to the metal atom (lone pair e- repulsion) but otherwise two different Nitrogens with lone pairs, for example, in the same m...
Sat Dec 05, 2020 4:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook Exercise 9C.7
Replies: 3
Views: 26

### Re: Textbook Exercise 9C.7

To further Lea's response, you want to look for two sites on the ligand that can realistically bond to two sites in the coordination complex- Lea did a good job describing how it's more realistic for the two groups with N that are closer to bond to the same metal in a coordination complex, so consid...
Sat Dec 05, 2020 3:05 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating pH with H+ or H3O+
Replies: 3
Views: 44

### Calculating pH with H+ or H3O+

Is it possible for an acidic solution to have a different number of moles of H+ and H3O+? (like if there aren't enough H+ for H20?) Or is this not possible in acidic compounds in aqueous solution.

If so, which would you use to calculate the pH of the solution?
Sat Dec 05, 2020 11:50 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strengths of Acids: Polarity
Replies: 6
Views: 63

### Strengths of Acids: Polarity

When looking at a list of strong acids, I see polar covalent compounds, but I don't quite understand if strong acids or more or less polarizable than weak acids?
Sat Dec 05, 2020 11:49 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Oxoacids?
Replies: 4
Views: 42

### Oxoacids?

What are oxoacids and their application? Are they in organic or inorganic compounds? When are oxoacids considered in the scope of this unit?
Sat Dec 05, 2020 11:47 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Stability of Anions Considering Strengths of ACids
Replies: 4
Views: 30

### Stability of Anions Considering Strengths of ACids

When characterizing the strengths of acids, one aspect to consider is resonance. I think this has something to do wih the stability of an anion and delocalizing the negative charges. How do we determine the stability of an anion and how does that correspond with the strength of an acid? How does res...
Sun Nov 29, 2020 5:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #20
Replies: 5
Views: 64

### Sapling #20

How do we know that one of the bonds with the As and O atoms in the As)4(3-) molecule has to be a double bond? How can I recognize this trend in further mleculres? Is it just bc the As is the central atom?
Sun Nov 29, 2020 4:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Tips on remembering shapes based on atoms in structure?
Replies: 3
Views: 38

### Tips on remembering shapes based on atoms in structure?

I was thinking Quizlet haha but I want to have a better understanding than just going off of memorization; what's a tip to remember the structures and angles of molecules? I find myself referring to a table I printed that shows the atoms around the central atom and their shapes+angles, but I have so...
Sun Nov 29, 2020 4:44 pm
Forum: Sigma & Pi Bonds
Topic: Rotation on the Internuclear Axis
Replies: 2
Views: 24

### Re: Rotation on the Internuclear Axis

Hi! The internuclear axis is defined as the straight line connecting the center of the two atoms in a bond. For your first question, the sigma bond does have electron density on both sides of the axis, but the density directly overlaps the axis, as seen in the image below. However, a pi bond is als...
Sun Nov 29, 2020 4:42 pm
Forum: Dipole Moments
Topic: Tetrahedral Atoms and Dipole Moments
Replies: 7
Views: 46

### Tetrahedral Atoms and Dipole Moments

Will every tetrahedral molecule with different atoms around the central atom have a dipole moment? (ex: CH2Cl2)
Sun Nov 29, 2020 4:40 pm
Forum: Resonance Structures
Topic: Sapling 17 (Specifically Bond Angles)
Replies: 3
Views: 38

### Sapling 17 (Specifically Bond Angles)

How would you determine the possible bond angles in the various structures? I had difficulty building the different physical structures; how would the three possible structures look in 3D space and how would their angles differ (or really how do the structures of the two non-cylical structures look ...
Sun Nov 29, 2020 3:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Negative poles of molecules
Replies: 3
Views: 44

### Re: Negative poles of molecules

How would you determine a molecule's polarity based on the shape if the lewis structure appears to have an equal distribution of the charges? How would you determine the pole through the structure?
Sat Nov 28, 2020 11:23 pm
Forum: Sigma & Pi Bonds
Topic: Rotation on the Internuclear Axis
Replies: 2
Views: 24

### Rotation on the Internuclear Axis

I'm a bit confused about the diagram of the pi bond forming on the internuclear axis that shows electron density on both sides of the internuclear axis. Doesn't the sigma bond also show electron density on both sides of the internuclear axis? Also, how are pi bonds formed then if not end to end. Las...
Mon Nov 23, 2020 2:02 am
Forum: Hybridization
Topic: Sigma vs Pi Bonds
Replies: 10
Views: 66

### Re: Sigma vs Pi Bonds

I found this image on Chem Libre texts that might be helpful in visualizing the different bonds visually:

Mon Nov 23, 2020 1:15 am
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle tips
Replies: 10
Views: 64

### Re: bond angle tips

Theoretically if you know the geometry of a molecule, like how many bonds are in the same plane, you could divide that 360 degrees by that number; honestly, though, it is probably wiser to just use Quizlet to memorize or become familiar with the unique bond angles.
Mon Nov 23, 2020 1:12 am
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Viscosity/Surface Tension
Replies: 7
Views: 212

### Re: Viscosity/Surface Tension

Viscosity and Surface tension are directly related to one another; increase viscosity then the surface tension increases. This is due to the intermolecular forces between molecules. Take a look at water! Water has surface tension that stems from hydrogen bonding between H20 molecules, this means th...
Mon Nov 23, 2020 1:07 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Instantaneous Dipoles
Replies: 5
Views: 24

### Re: Instantaneous Dipoles

If its rod shaped then either end of the rod is likely partially charged and another charged rod can line up antiparallel making the dipole moment at either end of each particle very close to the dipole moments on the other particle. This means that both dipole moments on both molicules are interac...
Mon Nov 23, 2020 1:04 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Why are hydrogen bonds so strong relative to other dipole-dipole bonds?
Replies: 11
Views: 131

### Re: Why are hydrogen bonds so strong relative to other dipole-dipole bonds?

Hydrogen bonding is so strong among dipole-dipole interactions because it itself is a dipole-dipole interaction with one of the strongest possible electrostatic attractions. Remember that hydrogen bonding cannot occur unless hydrogen is covalently bonded to either oxygen, nitrogen, or fluorine. Thi...
Sun Nov 15, 2020 11:16 pm
Forum: Ionic & Covalent Bonds
Topic: Saplong 15
Replies: 6
Views: 35

### Saplong 15

On Sapling Question 15, why is HF the only compound listed (hydrogen halide) thta remains covalently bonded in water of HF, HBr, HCl, and HI?
Sun Nov 15, 2020 10:30 pm
Forum: Bond Lengths & Energies
Topic: Bonds and Accepting Electrons
Replies: 2
Views: 36

### Bonds and Accepting Electrons

Sapling Question #6 says 'Molecules with polar double bonds also accept electrons" making CO2 a Lewis Acid. Why is that?
Sun Nov 15, 2020 10:23 pm
Forum: Resonance Structures
Topic: Building Resonance Structures with Similar Formal Charges
Replies: 2
Views: 33

### Building Resonance Structures with Similar Formal Charges

In building resonance structures with similar distributions of formal charges, how do we determine which is more favorable? I've looked at a few problems with different double/single bonds, same distributions of formal charges, and remember reading somewhere that favorability is influenced by least ...
Sun Nov 15, 2020 10:12 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Consequences of polarizability
Replies: 4
Views: 141

### Re: Consequences of polarizability

Since polarizability increases for larger cations, does this mean larger compounds overall have stronger IMFs? Also, how does a dipole moment influence/is influenced by polarizability?
Sun Nov 15, 2020 9:37 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: dipole moments
Replies: 10
Views: 54

### Re: dipole moments

Would you only draw these for a dipole moment though? I guess I want to know when you would even draw the arrows; would it be in an ionic compound specifically, or the temporary dipole moment in covalent compounds? Also, I wanted to clarify you wouldn't have a dipole moment in a compound made of the...
Sun Nov 15, 2020 9:24 pm
Forum: Bond Lengths & Energies
Topic: Energies for interactions
Replies: 4
Views: 22

### Re: Energies for interactions

When reviewing interactoins between ion-ion and ion-dipole interactions, where do the energies come from? I understand that, in an ion-ion example, the two are attracted to each other, but I don't undersatnd how that contributes to the negative energy (being released)? It is better not to think of ...
Sun Nov 15, 2020 9:20 pm
Forum: Dipole Moments
Topic: London Dispersion forces
Replies: 14
Views: 75

### Re: London Dispersion forces

This might be a silly question but are LDF's, dipole induced dipole, and induced dipole-induced dipole the same? My mind is spinning at hte use of the word dipole over and over ahaha.
Sun Nov 15, 2020 7:44 pm
Forum: Bond Lengths & Energies
Topic: Energies for interactions
Replies: 4
Views: 22

### Energies for interactions

When reviewing interactoins between ion-ion and ion-dipole interactions, where do the energies come from? I understand that, in an ion-ion example, the two are attracted to each other, but I don't undersatnd how that contributes to the negative energy (being released)?
Sun Nov 15, 2020 2:56 pm
Forum: Ionic & Covalent Bonds
Topic: What do delta positive and delta negative refer to?
Replies: 3
Views: 28

### What do delta positive and delta negative refer to?

I know they have to do with the general charge as the electron is puleld between atoms, but I'm not sure specifically what they refer to and how they apply specifically to ionic and covalent bonding-- I did catch how electronegativity is at play there, but still not sure how the delta is involved. A...
Sun Nov 08, 2020 11:44 pm
Forum: Resonance Structures
Topic: Valence Electrons [ENDORSED]
Replies: 43
Views: 328

### Re: Valence Electrons[ENDORSED]

Is there a way to use the electron configurations to know the valence electrons in transition metals?
Sun Nov 08, 2020 11:42 pm
Forum: Resonance Structures
Topic: Oxidation Number
Replies: 9
Views: 56

### Re: Oxidation Number

Does an oxidation number pertain to both loss and gain? How does it relate to reduciton?
Sun Nov 08, 2020 11:40 pm
Forum: Octet Exceptions
Topic: Exceptions
Replies: 9
Views: 52

### Re: Exceptions

I would agree with what was said above, the way to tell that they are exceptions is that if there is no way for the middle atom to achieve a full octet. You do not need to memorize all of them, I would say its more favorable if you recognize them instead. Is this a way to tell for individual atoms ...
Sun Nov 08, 2020 11:39 pm
Forum: Octet Exceptions
Topic: Exceptions
Replies: 9
Views: 52

### Re: Exceptions

Is there a way to use either periodic table trends (or indications or orbitals) or just the character of an element to determine of it's an exception to the rule?
Sun Nov 08, 2020 11:35 pm
Forum: Lewis Structures
Topic: Lewis Dot Structure
Replies: 11
Views: 91

### Re: Lewis Dot Structure

Wouldn't you put one on each side first before you match the pairs of electrons? or am I just thinking of spin... Actually I think this applies since we have to think how the electron alone in an orbital and a pair represents two that are in the same one. Overall you'd probably have to be conscious ...
Sun Nov 08, 2020 11:04 pm
Forum: Lewis Structures
Topic: Bond Character
Replies: 6
Views: 82

### Re: Bond Character

I believe bond character could also be associated with ionic vs covalent nature which could be related overall to the bond lengths. It could be similar to ionic character, where ions contribute to another molecule or atom's resonance. Replying to follow this post though because I would like a furthe...
Sun Nov 08, 2020 11:01 pm
Forum: Ionic & Covalent Bonds
Topic: London dispersion forces
Replies: 12
Views: 55

### Re: London dispersion forces

I believe most replies above have the definition of London dispersion forces. Here is the order of bond strengths from strongest to weakest 1. Ionic bonds 2. Covalent bonds 3. Dipole Dipole bonds 4. Van der Waals (London dispersion) Are London Disperson/Van der Waals considered a form of bond? Or a...
Sun Nov 08, 2020 10:56 pm
Forum: Student Social/Study Group
Topic: Midterm 2 Study Group
Replies: 25
Views: 159

### Re: Midterm 2 Study Group

Thanks for posing this!
Sun Nov 08, 2020 10:55 pm
Forum: Trends in The Periodic Table
Topic: Ionization and electron affinity
Replies: 6
Views: 45

### Re: Ionization and electron affinity

Hi, I just wanted to pose a further quesiton; electron affinity involves energy released when an electron is added to an atom; even though it only applies to atoms in their gaseous form, does this essentially hold true with the trend of ionization energy and electronegativity always? Additionally, i...
Sun Nov 01, 2020 8:33 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 4s and 3d
Replies: 14
Views: 104

### Re: 4s and 3d

Quick question: why do electrons in the s orbital have a lower energy than p electrons ? It is just due to theshape of the orbital? And how are different orbitals grouped into the same energy level if some have lower or higher energy than others? (My only understanding in the exception for Cr and Mn...
Sun Nov 01, 2020 8:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 337
Views: 139721

### Re: Saying Thank You to Dr. Lavelle

Thank you to Dr. Lavelle for the enthusiasm, including the pre-lecture music and the post-lecture jokes lately. They are absolutely precious and make watching recorded lectures still a bit engaging or fun. Definitely yhe best part of catching up on online school work
Sun Nov 01, 2020 7:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: S and P orbitals and shielding
Replies: 2
Views: 12

### Re: S and P orbitals and shielding

I believe that electrons in s orbitals can shield thosein p orbitals at the same level due to the shape, since the S orbital is spherical and the p orbital is more of like 2 balloons, if they get in the way then I believe shielding can occur. Anyone else also feel free to add haha! Edit: found this ...
Tue Oct 27, 2020 3:15 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency Condition
Replies: 2
Views: 24

### Re: Bohr Frequency Condition

Also, when would we use the associated equation (En= -hR/n^2) vs the Rydberg equation?
Tue Oct 27, 2020 3:14 am
Forum: DeBroglie Equation
Topic: When to use De Broglie equation? [ENDORSED]
Replies: 7
Views: 111

### Re: When to use De Broglie equation?[ENDORSED]

On the formula sheet, we have the De Broglie equation, and another one that is E=momentum times c. In which case would we use one or the other? Or are both valid?
Tue Oct 27, 2020 3:12 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency Condition
Replies: 2
Views: 24

### Bohr Frequency Condition

What particularly is the Bohr Frequency Condition; to clarify, is it referring to the frequency of an electron jumping certain energy levels when quantized?
Mon Oct 26, 2020 10:57 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy v. Molecular Spectroscopy
Replies: 3
Views: 54

### Re: Atomic Spectroscopy v. Molecular Spectroscopy

Hi Neel, I'm just going to assume the energy differences are vastly different (for lack of a better term) due to the electrongeativity of an atom of an element as opposed to the attraction (pull) of either a stable or unstable compound. I do not recall seeing any probelms requiring an ability to dif...
Sun Oct 25, 2020 10:53 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: What n1 and n2 represents in the Rydberg Equation?
Replies: 9
Views: 87

### Re: What n1 and n2 represents in the Rydberg Equation?

How does the negative sign play into the Ryderg equation? Some formulas are written -R and others with the n1 and n2 switched. I just wanted clarification on whether we could do the calculation either way and just remember to flip the sign? Or at what point would we need to before it influences the ...
Sun Oct 25, 2020 10:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: orbital concepts
Replies: 6
Views: 63

### Re: orbital concepts

I was wondering if anyone could clarify how orbitals relate to the wave function in Schrodinger's equation, and how uncertainty plays into that? That's my only personal understanding of the connection between uncertainty and probability of the electrons being within that specific space.
Sun Oct 25, 2020 9:57 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Measuring Uncertainty- Homework 1B.27
Replies: 4
Views: 66

### Re: Measuring Uncertainty- Homework 1B.27

I believe it gives one answer as you would only use the upper bound of the uncertainty you know to find the minimum value for the other. In this case it looks like the textbook is only using the value within the range; knowing that the deltap deltav is a constant value in relation to h/4pi, maybe ju...
Sun Oct 25, 2020 9:29 pm
Forum: Einstein Equation
Topic: question on homework #7
Replies: 6
Views: 40

### Re: question on homework #7

I'm pretty good at making small mistakes in unit conversions; I find it helps if I just set up the conversion with a dimensional analysis-type setup so the units cancel and I plug into the calculator so I don't make an error with moving the decimal space. Sounds lowkey convoluted or lazy of me but t...
Sun Oct 25, 2020 9:23 pm
Forum: *Shrodinger Equation
Topic: Hamiltonian
Replies: 3
Views: 49

### Re: Hamiltonian

The Hamiltonian refers to taking the double-derivative of the wave function; think of how the wave function is either a sine or cosine function. The double derivative of sine or cosine would just be sine or cosine but with a different sign. Schrodinger's equation is actually a differential equation ...
Mon Oct 19, 2020 1:04 am
Forum: Photoelectric Effect
Topic: When are electrons excited vs ejected
Replies: 16
Views: 131

### Re: When are electrons excited vs ejected

One thing I have a question about is why the electron goes up and them combes back down when excited by a photon; I understand the Zeff or charge of the nucleus may pull the elctron back down energy levels, but could photos also just ionize atoms, as in causing them to lose their electrons entirely?...
Mon Oct 19, 2020 12:55 am
Forum: Photoelectric Effect
Topic: Light Intensity
Replies: 23
Views: 110

### Re: Light Intensity

Only slightly related I suppose, but if the intensity of light is increased, I imagine the wave model would have higher peaks, correct? I thought the height of the peaks and the distance between them (wavelenght) correlated? So then light doesn't act in the wave form because the greater intensity in...
Mon Oct 19, 2020 12:51 am
Forum: Photoelectric Effect
Topic: Sapling #4 Homework Part 2
Replies: 9
Views: 121

### Re: Sapling #4 Homework Part 2

Essentially what I've gotten from this post is that after finding the work function, I would need to break up the energy needed to release each electron between photons. So you cannot actually find how many electrons would be ejected with the given information without thw work function as each proto...
Mon Oct 19, 2020 12:34 am
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1298

### Re: How are you studying?

I'm a bit behind in the overall class content as I'm finding it hard to balance classes at the moment, but to study concepts I don't understand, I'll rewrite my notes and focus on making the notes look pleasant, and sprinkle in some practice problems. This way, I'll remember the concepts based on th...
Mon Oct 19, 2020 12:31 am
Forum: Photoelectric Effect
Topic: Photoelectric experiment vs atomic spectra
Replies: 5
Views: 57

### Re: Photoelectric experiment vs atomic spectra

Wait so in my understanding I see hte photoelectric effect as causation for atomic spectra; otherwise, the effect AFFECTS the spectra, in that the light emitted from an electron dropping energy levels causes that line of light which helps place atoms (or molecules) on the spectra in their respective...
Sun Oct 11, 2020 11:16 pm
Forum: Limiting Reactant Calculations
Topic: Double Check my Understanding
Replies: 10
Views: 140

### Re: Double Check my Understanding

Hello, I also would like to pose a question in terms of understanding with limiting reactant questions; if we ignore the stoich coefficients, we would be focusing on just the mass, correct? So while the moles of a compound do indicate the amount of an element in terms of mass, we still need to keep ...
Sun Oct 11, 2020 11:12 pm
Forum: Molarity, Solutions, Dilutions
Topic: Sapling HW question
Replies: 4
Views: 110

### Re: Sapling HW question

For this question, you should multiply the mL of the reactant you know (2-butanone) by density to get the grams of this compound. you should also find out how many mol of product were created using the molar mass. When solving this for the yield, I assumed 2-butanone and the product given were in a ...
Sun Oct 11, 2020 11:06 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Textbook Homework E9
Replies: 6
Views: 105

### Re: Textbook Homework E9

I believe that looking at the periodic table will give you a sense of the valence electrons for each element, so knowing this on top of the charges of several polyatomic ions will help in building compounds. This way you can assume the charges of the elements as individual atoms and what they would ...
Sun Oct 11, 2020 10:32 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Combustion Reactions
Replies: 6
Views: 76

### Re: Balancing Combustion Reactions

In a combustion reaction, a hydrocarbon is combusted (burns?) in oxygen, and the resulting products are carbion dioxide and water. I was wondering is hydrocarbons must always follow the same structure (same amount of carbons and oxygens), or if it doesn't matter the empirical formulas as long as the...
Sat Oct 10, 2020 8:54 pm
Forum: Limiting Reactant Calculations
Topic: Question 10 homework
Replies: 9
Views: 128

### Re: Question 10 homework

Hi, trying to understand how the strucure creates the molecular mass, I'm thinking each vertex represents one carbon plus an additional hydrogen if not already bonded to another distinct molecule? So using this information, could add the mass of carbon and hydrogen for each vertex since the carbons ...