Search found 70 matches

by Annie Chantasirivisal_4G
Wed Jan 22, 2020 9:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6B.9, Kw
Replies: 1
Views: 9

6B.9, Kw

Screen Shot 2020-01-22 at 9.11.20 PM.png When I was doing this problem, I wanted to try using Kw=[H3O+][OH-] for extra practice with that formula, however the concentration I got for [OH-] in i. when using the Kw formula was different from the concentration I got when using [OH-]=10^-pOH. Is this b...
by Annie Chantasirivisal_4G
Wed Jan 22, 2020 9:15 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 6B 9
Replies: 3
Views: 28

Re: 6B 9

Yes, they are called superacids and superbases! "Super" in this case meaning they exist beyond the standard pH scale of 1 to 14 that we are accustomed to. I don't think this class will deal with them much, aside from the fact that we know they exist.
by Annie Chantasirivisal_4G
Sun Jan 19, 2020 3:05 pm
Forum: Administrative Questions and Class Announcements
Topic: PLFs on MLK?
Replies: 1
Views: 27

PLFs on MLK?

Hello,

Since tomorrow is a holiday, I just wanted to make sure: are peer learning sessions in Covel canceled tomorrow night?
by Annie Chantasirivisal_4G
Thu Jan 16, 2020 8:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5l.29
Replies: 5
Views: 21

Re: 5l.29

I have a followup question: Why did you all decide to set x = to change in equilibrium for H2 or Cl2, and 2X = change in HCL instead of saying x = change in HCL and 0.5X = change in H2 and Cl2? I did it the second way and I got the wrong answer. I'm trying to understand conceptually why my way is w...
by Annie Chantasirivisal_4G
Wed Jan 15, 2020 8:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1
Replies: 1
Views: 25

Re: Test 1

I can't find these concepts in my notes either, but a UA said that Dr. Lavelle could use these concepts in terms of reactions at equilibrium. Like for ATP hydrolysis, the reaction could be written as ATP ⇌ ADP + phosphate group, etc.
by Annie Chantasirivisal_4G
Wed Jan 15, 2020 8:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5l.29
Replies: 5
Views: 21

Re: 5l.29

Hi! The way I did it is by setting up the ice table, which will end up with HCl having 0.22-2x, and H2 and Cl2 each having x at equilibrium. Then, you plug those values into where they would go in the equilibrium constant ((PH2)(PCl2))/((PHCl)^2) which gives you x^2/(0.22-2x)^2 is equal to K, 3.2 x ...
by Annie Chantasirivisal_4G
Mon Jan 13, 2020 10:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.39
Replies: 4
Views: 50

5.39

"In an experiment, 0.020 mol NO2 was introduced into a flask of volume 1.00 L and the reaction 2NO2(g)⇌N2O4(g) was allowed to come to equilibrium at 298 K. (a) Using information in Table 5G.2, calculate the equilibrium concentrations of the two gases. (b) The volume of the flask is reduced to h...
by Annie Chantasirivisal_4G
Mon Jan 13, 2020 9:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kc
Replies: 2
Views: 11

K vs Kc

So, I understand the distinction between Kp and Kc, one for partial pressure and the other for concentration, but for table 5G.2, what is their difference? How would we know whether to use K or Kc when being referred to it by a textbook problem (such as 5.39)?
IMG_0115.jpg
by Annie Chantasirivisal_4G
Mon Jan 13, 2020 9:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 5.35
Replies: 3
Views: 27

Re: Homework 5.35

IMG_0113.jpg

(That's the graph in case anyone needs it, hopefully I attached it right ><)

I'm still a bit confused on how to write the balanced equation... how can you tell from the graph that there were 2 moles A, 1 mol B, and 2 moles C??
by Annie Chantasirivisal_4G
Sat Jan 11, 2020 6:01 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding inert gas [ENDORSED]
Replies: 9
Views: 39

Re: Adding inert gas [ENDORSED]

Will helium always be the inert gas we would add, or what other gases could also work?
by Annie Chantasirivisal_4G
Sat Jan 11, 2020 5:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Simplifying cubic equations
Replies: 3
Views: 12

Simplifying cubic equations

Will we always be given a small K in order to simplify cubic equations in this class?

If K was big, how do you go about solving a cubic equation?
by Annie Chantasirivisal_4G
Sat Jan 11, 2020 5:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Thermodynamically Stable
Replies: 3
Views: 26

Re: Thermodynamically Stable

Cl2 is more stable than F2 because there was less dissociation from Cl2 to Cl atoms. When comparing the two reactions, Cl2 ended up with an essentially unchanged concentration of 0.0010 mol.L^-1, while the concentration of Cl atoms at equilibrium was 1.1 x 10^-5 mol.L^-1; on the other hand, F2 had a...
by Annie Chantasirivisal_4G
Sat Jan 11, 2020 5:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Aqueous state [ENDORSED]
Replies: 1
Views: 13

Aqueous state [ENDORSED]

When calculating the equilibrium constant, we omit liquids and solids because their concentrations are either insignificant or there is no such thing as their concentration. However, how do we treat aqueous solutions? What is different about aqueous solutions from liquids that prevent it from gettin...
by Annie Chantasirivisal_4G
Mon Jan 06, 2020 7:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post assessment part 2
Replies: 1
Views: 28

Post assessment part 2

The equilibrium constant, KP, for the reaction SO2 (g) + O2 (g) ⇌ SO3 (g) at 700 K is 3 x 10^4. A mixture of SO2, O2, and SO3, each at 65 bars was introduced into a container at 700 K. Is the reaction at equilibrium? If not, does SO3 tend to form or decompose? I'm having trouble understanding this q...
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 9:22 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 4081

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

MMckinney_4H wrote:For number 34, why are two moles of OH produced for every mole of CaO?


CaO separates into Ca^2+ and O^2-, and O^2- can be added with H2O to form 2OH-, thus 1 mole of CaO ends up producing 2 moles of OH-.
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 5:49 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 4081

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

For mini marshmallow 2c, why is the coordination number for K[Cu(en)2(CN)2] 6? It is six because en is a bidentate, so it will bind at two areas; since there are two en, that would mean 4 binding sites, in addition to the 2 cyanides, for a total of 6 bonds bound to copper, thus coordination number 6.
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 3:51 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 4081

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

Hey guys, he just posted marshmallow answers rn. posting in case anyone has it bookmarked/subscribed.
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 3:33 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating vs Polydentate Ligands
Replies: 3
Views: 51

Re: Chelating vs Polydentate Ligands

A chelating ligand is one that binds to a cation in more than one location, thus it is polydentate. Some of the common polydentate ligands are oxalate (bidentate) ethylenediamine (bidentate) diethylenetriamine (tridentate) ethylenediaminetriacetate (EDTA - hexadentate) porphyrin (tetradentate) I do...
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 3:23 pm
Forum: Administrative Questions and Class Announcements
Topic: Main focus
Replies: 3
Views: 36

Re: Main focus

Based on Dr. Lavelle's review of past final exam questions, I think the topics are all spread pretty evenly amongst the 8 questions, so I don't think material post-midterm would have a higher emphasis on the final. Anything in our notes/his slides is fair game :')
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 3:17 pm
Forum: Naming
Topic: Molecular formula for long ligands
Replies: 2
Views: 20

Molecular formula for long ligands

Sorry if this has been asked already but I can't find the answer :c Does anyone know if in the final we are allowed to use abbreviations of long ligands such as (en) instead of NH2CH2CH2NH2 when writing out the molecular formulas from being given the name of the coordination compounds? For example, ...
by Annie Chantasirivisal_4G
Sat Dec 07, 2019 3:07 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 4081

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

For #17, what does it mean by the “hybridization of each lone pair”? Is it supposed to be the hybridization of each central atom? Can someone answer this please! I am wondering the same thing. Hybridization of lone pairs can be determined by looking at the atom that the lone pairs are attached to. ...
by Annie Chantasirivisal_4G
Sun Dec 01, 2019 8:27 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sig Figs for pH
Replies: 1
Views: 16

Sig Figs for pH

The book states: "A Note on Good Practice: The number of digits following the decimal point in a pH value is equal to the number of significant figures in the corresponding molar concentration, because the digits preceding the decimal point simply report the power of 10 in the data (as in log 1...
by Annie Chantasirivisal_4G
Fri Nov 29, 2019 7:12 pm
Forum: Bronsted Acids & Bases
Topic: Trichloroacetic acid vs acetic acid
Replies: 2
Views: 26

Re: Trichloroacetic acid vs acetic acid

Trichloroacetic acid is just acetic acid with 3 Cl atoms instead of 3 H. Therefore, the Cl atoms have a stronger pull on the bonds of the carboxyl group, loosening the OH bond and making H+ions more likely to dissociate. When the bonds of the carboxyl group are pulled, are all of the bonds loosenin...
by Annie Chantasirivisal_4G
Fri Nov 29, 2019 6:46 pm
Forum: General Science Questions
Topic: hydrogen vs hydronium
Replies: 5
Views: 37

Re: hydrogen vs hydronium

The hydrogen ion is often used in place of hydronium to simplify things. However, you should know that the hydronium ion better represents what is actually seen. Right, thank you! In reference to what is "actually seen", are you referring to hydronium in an acid? Like when a hydrogen ion ...
by Annie Chantasirivisal_4G
Fri Nov 29, 2019 6:43 pm
Forum: General Science Questions
Topic: hydrogen vs hydronium
Replies: 5
Views: 37

Re: hydrogen vs hydronium

Nevermind, just saw in my notes that hydronium is H3O+, which is completely different from hydrogen, H. Sorry!
by Annie Chantasirivisal_4G
Fri Nov 29, 2019 6:39 pm
Forum: General Science Questions
Topic: hydrogen vs hydronium
Replies: 5
Views: 37

hydrogen vs hydronium

This is probably a silly question, but I often hear Dr.Lavelle mentioning hydronium ion during lecture in place of hydrogen so I just wanted to make sure, hydronium and hydrogen are interchangeable names, right? Or is there a difference in structure somehow that I'm not catching?

Thanks!
by Annie Chantasirivisal_4G
Fri Nov 29, 2019 6:33 pm
Forum: Bronsted Acids & Bases
Topic: Trichloroacetic acid vs acetic acid
Replies: 2
Views: 26

Trichloroacetic acid vs acetic acid

Hi,

I did not quite catch Dr.Lavelle's explanation for why trichloroacetic acid was a stronger acid than acetic acid... does anyone understand why?
by Annie Chantasirivisal_4G
Wed Nov 20, 2019 7:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2.63
Replies: 1
Views: 16

2.63

Estimate the bond angles of peroxyacetylnitrate. *I don't know how to attach an image sorry :c* Does anyone understand why angle b has to be 109.5 degrees? I can see that the other two angles are trigonal planar so it explains the 120 degrees, which I assumed also applied to angle b, but since oxyge...
by Annie Chantasirivisal_4G
Wed Nov 20, 2019 7:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral
Replies: 6
Views: 38

Octahedral

Hi, this might be a silly question, but does anyone know why an octahedral is an octahedral? Where does the 8 from "octa-" come from if there are only 6 atomic orbitals?
by Annie Chantasirivisal_4G
Wed Nov 20, 2019 7:09 pm
Forum: General Science Questions
Topic: Chem BL
Replies: 7
Views: 57

Re: Chem BL

Does anyone know if it also applies to 14CL? Like should we take CL after we take 14C as well?
by Annie Chantasirivisal_4G
Wed Nov 20, 2019 7:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lewis structure of organic compunds
Replies: 5
Views: 42

Re: lewis structure of organic compunds

For instance, CH3CH2OH. How would I know how to draw this compound? So, that compound is composed of carbon, hydrogen and oxygen atoms. Of the three, their electronegativities, from lowest to highest, are H<C<O. Usually the most electropositive element goes to the middle, but since hydrogen can onl...
by Annie Chantasirivisal_4G
Wed Nov 20, 2019 6:39 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 2
Views: 33

Re: Cisplatin

Cisplatin has two chlorine atoms on one side that allow it to bind to one of the nitrogens in the nucleotide base guanine, specifically N7 of guanine, that has a lone pair. When those chlorine atoms form two bonds (each forming a bond), it's a lot more difficult for cell division to occur and thus t...
by Annie Chantasirivisal_4G
Sun Nov 17, 2019 6:39 pm
Forum: Hybridization
Topic: 2.57
Replies: 1
Views: 17

2.57

Hello! Just wanted to check my work since this problem's answer was not in the solutions manual. 2.57: Acetonitrile, CH3CN, is used as a solvent in the pharmaceutical industry. Describe the structure of the CH3CN molecule in terms of hybrid orbitals, bond angles, and σ- and π-bonds. The N atom is a ...
by Annie Chantasirivisal_4G
Sat Nov 16, 2019 4:13 pm
Forum: Dipole Moments
Topic: Cancelling dipole moments
Replies: 9
Views: 74

Cancelling dipole moments

I'm having trouble visualizing how dipole moments cancel each other out for molecules that have more than two dipoles. I can kind of see how the C-Cl bonds in trans-dichloroethene cancel out, since they're on opposite sides and their vectors are going in opposite directions, but how do I visualize t...
by Annie Chantasirivisal_4G
Sat Nov 16, 2019 4:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lewis structure of organic compunds
Replies: 5
Views: 42

Re: lewis structure of organic compunds

Do you have an example of a difficult compound? I'm assuming most homework problems use easier compounds, but whenever they get challenging for me or if I get it wrong initially, I just start off again with evaluating the most electropositive element and putting it in the middle, then spread out the...
by Annie Chantasirivisal_4G
Sat Nov 16, 2019 3:24 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: biological examples?
Replies: 3
Views: 18

Re: biological examples?

There's two hydrogen bonds in the Adenine and Thymine base pair, and three hydrogen bonds in the Guanine and Cytosine base pair.

Hydrogen bonding also plays a role in maintaining the shape of proteins, DNA, RNA, cellulose, etc.
by Annie Chantasirivisal_4G
Thu Nov 14, 2019 7:41 pm
Forum: General Science Questions
Topic: Midterm
Replies: 2
Views: 20

Re: Midterm

You are not limited to your TA, you can go to other TAs as well. The solutions are also online on the class website, so if you feel like maybe you missed out on points you should compare answers with the solutions to see how yours differ.
by Annie Chantasirivisal_4G
Thu Nov 14, 2019 7:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework 2E.1
Replies: 4
Views: 25

Re: Homework 2E.1

Since 2E.1 already gives us the shape of the molecule, would we have to find what molecule fits that shape when you "draw it out" to see the lone pairs?
by Annie Chantasirivisal_4G
Fri Nov 08, 2019 5:59 pm
Forum: Lewis Structures
Topic: Hybridization
Replies: 2
Views: 24

Hybridization

Why do electrons undergo hybridization?
Just had discussion today and was totally confused by the end of it... In the BH3 example, my TA drew an electron from Boron in the 2s state going up into the 2p state... why does it do that?
by Annie Chantasirivisal_4G
Fri Nov 08, 2019 5:51 pm
Forum: Bond Lengths & Energies
Topic: negative Ep
Replies: 5
Views: 40

negative Ep

Does anyone understand why Ep is always negative for interaction potential energy?

I missed Dr. Lavelle's explanation... why does a negative Ep lead to attractive force?
by Annie Chantasirivisal_4G
Fri Nov 08, 2019 5:45 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: Dispersion
Replies: 3
Views: 16

Re: Dispersion

The way I understood it, because there were different amounts of carbon in each substance, that affected the number of electrons since the more carbons (or even just atoms in general) that you have, the more electrons there will be. In the interaction potential energy equation we went over in class ...
by Annie Chantasirivisal_4G
Fri Nov 08, 2019 5:36 pm
Forum: Student Social/Study Group
Topic: Midterm
Replies: 3
Views: 43

Re: Midterm

It's difficult to explain because I don't remember the question word for word, but I found it really similar to the first question on the practice exam Dino Nuggets that UA Lyndon made where you're given molecules and you try to find mass percentage composition from there. I think it'd be helpful to...
by Annie Chantasirivisal_4G
Tue Nov 05, 2019 8:42 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic quantum number (m sub l)
Replies: 1
Views: 27

Magnetic quantum number (m sub l)

Hi guys, So I understand that the magnetic quantum number (m l ) can be found based on the angular momentum quantum number (l), where you just go from -l to +l, but I wanted to make sure... will m l =-1 always correspond to the x, such as if we were given n=2, l=1, and m l =-1 the referred state is ...
by Annie Chantasirivisal_4G
Sat Nov 02, 2019 3:24 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: What d to include when "counting valence electrons including d electrons"
Replies: 1
Views: 19

What d to include when "counting valence electrons including d electrons"

How do we know which d to include when counting valence electrons from electron configuration when they want us to include d electrons? For example, in 2A.1a Sb has an electron configuration of [Kr]4d10 5s2 5p3 but its valence electrons are only 5 electrons, while in 2A.1c Mn has an electron configu...
by Annie Chantasirivisal_4G
Tue Oct 29, 2019 11:30 pm
Forum: Lewis Structures
Topic: 2B.3d
Replies: 1
Views: 14

2B.3d

The question asks to draw lewis structures for BrF3. The answer drew Br with 10 valence electrons (three single bonds each connecting to F, and then two pairs of electrons at the non bonded side of Br at the top), but I do not understand why. I know it has something to do with being an exception to ...
by Annie Chantasirivisal_4G
Tue Oct 29, 2019 11:18 pm
Forum: Lewis Structures
Topic: Homework 2A 12
Replies: 3
Views: 27

Re: Homework 2A 12

The M in M2+ also refers to the metal with the charge 2+, so the book is asking for metals/elements with a charge of 2+ that work with the various electron configurations you listed.
by Annie Chantasirivisal_4G
Tue Oct 29, 2019 11:13 pm
Forum: Lewis Structures
Topic: 2B. 1C
Replies: 5
Views: 43

Re: 2B. 1C

Continuing from this, how would we know which atom would be the central atom? The book stated that "usually" the central atom would be listed first, but for ONF this clearly was not the case... how could we tell from the "usually" and exceptions?
by Annie Chantasirivisal_4G
Tue Oct 29, 2019 11:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Learning
Replies: 3
Views: 34

Re: Sapling Learning

Hey! I got an email about it, but it made it seem like everyone needs to trade in the code sleeve at the UCLA store? Do you know if this only applies to the people that SaplingLearning doesn't work for? Or should we all be trading in the code sleeve because SaplingLearning will be inactive after Oc...
by Annie Chantasirivisal_4G
Sat Oct 26, 2019 2:25 pm
Forum: Ionic & Covalent Bonds
Topic: Atomic Radius
Replies: 4
Views: 31

Re: Atomic Radius

Atomic radii decrease from left to right because going across a period is essentially adding another electron in the same shell/energy level; the next element would also have an increase nucleus since protons and neutrons are also being added to cancel out charges. Thus, that increase in nuclear cha...
by Annie Chantasirivisal_4G
Sat Oct 26, 2019 2:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Noble Gas Configuration
Replies: 2
Views: 11

Re: Noble Gas Configuration

I'm pretty sure that since we've been doing noble gas configurations in class examples, they would be acceptable for the test.
by Annie Chantasirivisal_4G
Sat Oct 26, 2019 12:07 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E. 21
Replies: 1
Views: 20

Re: 1E. 21

Hi, The question you posted was for 1E.20, but I'll try to answer it; to find the number of valence electrons, it would be handy to have a periodic table with you where you can look at the placement of the element, and then determine the electron configuration from there. For example, (a)Ta has an e...
by Annie Chantasirivisal_4G
Mon Oct 21, 2019 7:14 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Hw 1B.27
Replies: 3
Views: 55

Hw 1B.27

"A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00 ± 5.0 ms^-1. What is the minimum uncertainty in its position?" I didn't notice the additional "5.00 ±" in the question when I tried solving the problem at first, however I got the same answer as the book;...
by Annie Chantasirivisal_4G
Mon Oct 21, 2019 7:07 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Hw 1B.25 and ℏ symbol
Replies: 1
Views: 37

Hw 1B.25 and ℏ symbol

Does anyone understand 1B.25? “What is the minimum uncertainty in the speed of an electron confined within a lead atom of diameter 350. pm? Model the atom as a one-dimensional box with a length equal to the diameter of the actual atom.” I started off using Heisenberg’s uncertainty equation (delta p ...
by Annie Chantasirivisal_4G
Mon Oct 21, 2019 6:59 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electrostatic potential energy
Replies: 2
Views: 33

Electrostatic potential energy

I was reviewing my notes from last week, and I'm having trouble understanding this equation:

electrostatic potential energy ∝ (q1*q2)/r

what does each variable mean, and what type of problem would require us to use it?
by Annie Chantasirivisal_4G
Sat Oct 19, 2019 3:58 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Memorizing electron configuration
Replies: 3
Views: 36

Re: Memorizing electron configuration

https://www.chem.fsu.edu/chemlab/chm1045/e_config.html ^^^^ This website has a straightforward visual or how to remember the order of the electron configuration; what helped me remember the order is by writing the sublevels in order, with each number going down in column and the spdf across the row....
by Annie Chantasirivisal_4G
Sat Oct 19, 2019 3:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: S and D orbitals
Replies: 1
Views: 27

Re: S and D orbitals

Chromium and Copper are the only two exceptions where you would have to switch between the s and d orbitals. These two elements prefer to have a full or half full d sub-level because it is more stable than to have a d sub-level that's partially filled, so an electron from the 4s orbital would rise t...
by Annie Chantasirivisal_4G
Thu Oct 17, 2019 9:56 pm
Forum: Photoelectric Effect
Topic: HW 1B.5
Replies: 8
Views: 76

Re: HW 1B.5

So do we have to convert keV to J for all problems or is it specific to this one? Since the problem is asking for the wavelength, you would use the formula (lambda)=ch/e out of combining e=hv and c=v(lambda). The energy (140.511 keV) will be the denominator, but we'd want the units to cancel out fr...
by Annie Chantasirivisal_4G
Wed Oct 16, 2019 10:10 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: subshell calculations
Replies: 2
Views: 39

Re: subshell calculations

The subshell number (l) is also known as the angular momentum quantum number, which can be calculated by subtracting one from the principle quantum number, or in other words l=n-1. I'm not sure if it can be higher than 3 though, since the f-orbital is already at l=3, which would make n=4. I hope I'm...
by Annie Chantasirivisal_4G
Wed Oct 16, 2019 10:02 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: the fourth number?
Replies: 4
Views: 33

the fourth number?

hi guys! can anyone explain to me the significance of the fourth quantum number aka the spin magnetic quantum number? I'm having trouble understanding why it would be significant to know how the electrons are reacting in an atom compared to the other three numbers... like what more does it tell us a...
by Annie Chantasirivisal_4G
Sat Oct 12, 2019 8:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 1611

Re: Week 2 Homework Problems [ENDORSED]

What conversion would we use to turn the value into picometers? 1A.7 (a) The frequency of violet light is 7.1 3 10 14 Hz. What is the wavelength (in nanometers) of violet light? (b) When an electron beam strikes a block of copper, x-rays with a frequency of 2.0 3 10 18 Hz are emitted. What is the w...
by Annie Chantasirivisal_4G
Sat Oct 12, 2019 6:14 pm
Forum: Properties of Light
Topic: Balmer vs Lyman series
Replies: 4
Views: 53

Balmer vs Lyman series

Hello there! I understand the absorption level diagram being essentially the same thing as orbitals in electron shells, but I'm having trouble relating it to the Balmer and Lyman series. For 1A.11, the question states "In the spectrum of atomic hydrogen, several lines are generally classified t...
by Annie Chantasirivisal_4G
Sat Oct 12, 2019 5:10 pm
Forum: Properties of Light
Topic: ∝ notation
Replies: 2
Views: 33

∝ notation

Hi, I just got my hand on the solution manual and I wanted to make sure I understood this properly: In exercise 1A.3: Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. (a) The speed of the radiation decreases. (b) The wavelength of the ...
by Annie Chantasirivisal_4G
Fri Oct 11, 2019 7:55 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 5
Views: 74

Re: Sig Figs

It's better to apply the sig figs just to your answer because it will deviate less from the solution in the manual. If there are too many steps in between and you round too often with sig figs you could end up with an answer off by the hundredths or tenths depending on severity.
by Annie Chantasirivisal_4G
Mon Oct 07, 2019 9:01 pm
Forum: Limiting Reactant Calculations
Topic: Determining the equation of written formulas
Replies: 2
Views: 32

Determining the equation of written formulas

Does anyone understand how exactly to determine a formula from its written form? Like for example, exercise M.7 states "Solid boron can be extracted from solid boron oxide by reaction with magnesium metal at a high temperature. A second product is solid magnesium oxide." Solid boron oxide ...
by Annie Chantasirivisal_4G
Tue Oct 01, 2019 10:02 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Practice Problem E.1
Replies: 6
Views: 49

Re: Practice Problem E.1

The solution also stated the distance in kilometers, rather than meters, but I'm not sure why since the problem doesn't specify the unit of measurement.
by Annie Chantasirivisal_4G
Tue Oct 01, 2019 9:58 pm
Forum: Significant Figures
Topic: E1 Sig Figs
Replies: 4
Views: 55

Re: E1 Sig Figs

1.00 has 3 sig figs, so it would still be 1.73 x 10^14. Numbers after a decimal usually still count as part of the significant figures, even if it's the number 0, so if the number was 1.000000000 there would be 10 sigfigs. 320. would be 3 sigfigs. However, if there was no decimal and the 0 was just ...
by Annie Chantasirivisal_4G
Tue Oct 01, 2019 5:52 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Moles and Molar Masses E. 23
Replies: 2
Views: 53

Re: Moles and Molar Masses E. 23

Since the question is asking specifically for Cu2+ ions, you would be calculating the moles of only Cu2+ within 3.00g of CuBr2. 1. You'd first calculate the molar mass of CuBr2, which is approximately 63.55+(2*79.90)=223.35g*mol-1 2. Then you'd find the mass percentage composition of only Cu within ...
by Annie Chantasirivisal_4G
Tue Oct 01, 2019 11:37 am
Forum: Significant Figures
Topic: Determining how many sig figs to use
Replies: 3
Views: 55

Re: Determining how many sig figs to use

I'm also unsure of how to use sig figs when the word problem doesn't state a number, such as F.1 only showing a molecular model of Citral and asking for the percentage composition... not sure how the solution came up with 2 decimal places. But regarding "Is it based on the number in the problem...
by Annie Chantasirivisal_4G
Mon Sep 30, 2019 9:42 pm
Forum: SI Units, Unit Conversions
Topic: mol, g.mol and g.mol-1
Replies: 12
Views: 152

Re: mol, g.mol and g.mol-1

g.mol and g.mol-1 are not interchangeable, as the -1 in g.mol-1 is supposed to represent the mol being brought up as a numerator when it is originally a denominator, meaning it's g times mol-1. g.mol-1 can also be also written as g/mol, though I'm assuming there is a preference of g.mol-1 for this c...
by Annie Chantasirivisal_4G
Mon Sep 30, 2019 9:31 pm
Forum: Molarity, Solutions, Dilutions
Topic: Homework Problem E. 19
Replies: 2
Views: 60

Re: Homework Problem E. 19

Hi,

Problem E19 was not listed as a homework problem in the syllabus or objective 1, likely because Dr. Lavelle has yet to go over density or its relationship to mass and volume.

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