Search found 50 matches

by Joanne Kang 3I
Sat Dec 07, 2019 1:05 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5355

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

Paige Lee 1D wrote:For #1c on mini marshmallow, how do you know to choose NH4+ and not NO3- for the net ionic equation? Since they're both weak acids and bases


NO3- is the conjugate base of a STRONG acid, so NO3- is very stable/does not affect the pH.
The only thing affecting pH then would be NH4+ producing H3O+
by Joanne Kang 3I
Sat Dec 07, 2019 12:55 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5355

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

For mini marshmallows 2b, why is the coordination number 4?
by Joanne Kang 3I
Sat Dec 07, 2019 12:52 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5355

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

Ashley Osorio wrote:How would one phrase number 36C?? Also, 36B is both Amphoteric and amphiprotic, right?

Yes.
by Joanne Kang 3I
Sat Dec 07, 2019 12:50 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5355

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

min marshmallows 1c... why isn't it neutral?
by Joanne Kang 3I
Thu Dec 05, 2019 4:42 pm
Forum: Bronsted Acids & Bases
Topic: 6.21
Replies: 1
Views: 54

6.21

The two strands of the nucleic acid DNA are held together by hydrogen bonding between four organic bases. The structure of one of these bases, thymine, is shown below. (a) How many protons can this base accept? Why can't the Oxygen molecules be proton acceptors as well? They have lone pairs https://...
by Joanne Kang 3I
Wed Dec 04, 2019 7:25 pm
Forum: Identifying Acidic & Basic Salts
Topic: KF v KBr
Replies: 1
Views: 50

KF v KBr

Why is KF basic while KBr neutral even though both anions are in the same group?
by Joanne Kang 3I
Wed Dec 04, 2019 7:06 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C.21b
Replies: 3
Views: 125

6C.21b

Suggest an explanation for the different strengths of (b) acetic acid and formic acid.
Can someone please explain the answer to this? Thank u!
by Joanne Kang 3I
Fri Nov 29, 2019 11:36 pm
Forum: Naming
Topic: 9C.3d
Replies: 1
Views: 38

9C.3d

3d. Use the information in Table 9C.1 to write the formula for each of the following coordination compounds:
d. sodium bisoxalato(diaqua)ferrate(III)
I left my solutions manual at ucla.. What is the answer to this question? Thanku!
by Joanne Kang 3I
Fri Nov 29, 2019 11:31 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8245
Views: 1438732

Re: Post All Chemistry Jokes Here

Finals are coming...
but my last brain cells argon...
My gpa and social life argonna be gone soon too..
by Joanne Kang 3I
Fri Nov 29, 2019 11:27 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8245
Views: 1438732

Re: Post All Chemistry Jokes Here

Image
by Joanne Kang 3I
Fri Nov 29, 2019 10:35 pm
Forum: Bronsted Acids & Bases
Topic: 6A.17b
Replies: 5
Views: 69

6A.17b

State whether the following oxides are acidic, basic, or amphoteric:
b. SO3
Can someone please explain why this molecule is basic??
by Joanne Kang 3I
Fri Nov 29, 2019 10:32 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.1
Replies: 1
Views: 59

6B.1

1. The molar concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in the pH values of the two solutions?
Can someone please explain the solution for this question?
by Joanne Kang 3I
Sat Nov 23, 2019 11:56 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8245
Views: 1438732

Re: Post All Chemistry Jokes Here

When someone posts a really obvious question on Chem Community...
Everyone:
Image
by Joanne Kang 3I
Sat Nov 23, 2019 11:47 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: Hydrogen Bonding Sites
Replies: 3
Views: 83

Hydrogen Bonding Sites

Do hydrogen bonding sites include the lone pairs of the hydrogen bond within the molecule? Ex. H2O
by Joanne Kang 3I
Sat Nov 23, 2019 11:41 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8245
Views: 1438732

Re: Post All Chemistry Jokes Here

Image
by Joanne Kang 3I
Sat Nov 23, 2019 11:33 pm
Forum: Hybridization
Topic: Hybridization
Replies: 3
Views: 92

Re: Hybridization

Like the person above said, when the s character increases because there is a decrease in the p character. This means that there are less lone pairs and bonds contributing to the hybridization number. So if there are less lone pairs and bond overall, the bond angle between atoms in the molecule incr...
by Joanne Kang 3I
Wed Nov 20, 2019 11:51 am
Forum: Hybridization
Topic: 2F:7.d
Replies: 2
Views: 59

2F:7.d

Identify the hybrid orbitals used by the atom in boldface red type in each of the following species:
d. SeF3+

Why is the answer sp3?
Thanks
by Joanne Kang 3I
Fri Nov 15, 2019 4:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape v Electron Geometry
Replies: 4
Views: 66

Molecular Shape v Electron Geometry

What is the difference between molecular shape and electron geometry with regards to VESPR?
by Joanne Kang 3I
Fri Nov 15, 2019 4:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula Exceptions
Replies: 6
Views: 134

Re: VSEPR Formula Exceptions

Not sure. If you look up the VESPR theory chart, it can give you all the possibilities of VESPR shapes.
by Joanne Kang 3I
Fri Nov 15, 2019 4:51 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 5
Views: 164

Re: Polarizability

To make sure, you should draw the compound's lewis structure. When you draw it, you may notice that the bonds within it are polar, meaning one atom is more delta negative or positive than the other.
by Joanne Kang 3I
Fri Nov 15, 2019 4:45 pm
Forum: Bond Lengths & Energies
Topic: Bond lengths and lone pairs
Replies: 3
Views: 77

Re: Bond lengths and lone pairs

I think lone pairs affect bond lengths because lone pairs cause repulsion. Structures without lone pairs have no extra repulsion except from the atoms in the molecule. Minimal e- repulsion causes the max distance between atoms.
by Joanne Kang 3I
Fri Nov 15, 2019 4:38 pm
Forum: Dipole Moments
Topic: Xenon
Replies: 4
Views: 98

Xenon

Does anyone remember what Dr. Lavelle was saying about Xenon during lecture? Thanks
by Joanne Kang 3I
Sat Nov 02, 2019 2:42 pm
Forum: DeBroglie Equation
Topic: Lyndon's Workshop Worksheet Problem
Replies: 3
Views: 126

Re: Lyndon's Workshop Worksheet Problem

For the first question we just have to use Wavelength = Speed of light / Frequency. It's given us the frequency, just in the wrong units, MHz not Hz. Remembering SI stuff, M = mega = 1,000,000 = 10^6. Now we have 8.01 x 10^7 Hz Wavelength = 3 x 10^8 / 8.01 x 10^7 = 3.74272732 meters Wait but I thou...
by Joanne Kang 3I
Sat Nov 02, 2019 12:41 pm
Forum: DeBroglie Equation
Topic: Lyndon's Workshop Worksheet Problem
Replies: 3
Views: 126

Lyndon's Workshop Worksheet Problem

Can someone please give me the solutions to these questions? They are from the Week 3 Worksheets. 2. The CHEM radio station broadcasts at 80.1 MHz. Calculate the wavelength of the corresponding radio waves and tune in to the station one day. 4. Can an electron from the hydrogen atom be confined to i...
by Joanne Kang 3I
Sat Nov 02, 2019 12:33 pm
Forum: Molarity, Solutions, Dilutions
Topic: Workshop Sheets Help
Replies: 1
Views: 142

Workshop Sheets Help

Does anyone have the solutions for Lyndon's workshop sheets for "week 1 chem 14A learning session: High School Chem"??
If so, can you please put the answers to questions 6 and 8 below?
by Joanne Kang 3I
Fri Nov 01, 2019 11:12 pm
Forum: *Shrodinger Equation
Topic: ?
Replies: 2
Views: 172

?

Can someone please explain the significance of this equation and why we need to know it?
by Joanne Kang 3I
Fri Nov 01, 2019 11:04 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Work function units
Replies: 5
Views: 81

Re: Work function units

Yes. Work functions should always be in Joules and then you most likely also convert the moles to atoms as well(with Avogadro's num).
by Joanne Kang 3I
Fri Nov 01, 2019 10:59 pm
Forum: Administrative Questions and Class Announcements
Topic: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]
Replies: 52
Views: 5089

Re: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]

I believe Dr. Lavelle said that he would not include the last slide he went over in lecture, which was "Interactions Between Ions & Molecules". Other than that I think everything else can possibly be on the test.
by Joanne Kang 3I
Fri Nov 01, 2019 10:55 pm
Forum: Bond Lengths & Energies
Topic: Test?
Replies: 8
Views: 216

Test?

Will bond lengths and energies be on the midterm? What will not be on the midterm?
by Joanne Kang 3I
Mon Oct 28, 2019 4:49 pm
Forum: Lewis Structures
Topic: 2B.11c
Replies: 2
Views: 71

2B.11c

Draw the complete Lewis structure for each of the following compounds:
c. glycine, H 2 C(NH 2 )COOH, the simplest of the amino acids, the building blocks of proteins.

How do you know how to write the Lewis structure for a complex atom like this?
by Joanne Kang 3I
Sun Oct 27, 2019 10:35 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Coulombs Law
Replies: 1
Views: 60

Coulombs Law

Is Coulomb's law more greatly affected by the charges or by the distance?
by Joanne Kang 3I
Fri Oct 25, 2019 4:49 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 226
Views: 116271

Re: Advice from a Medical Student [ENDORSED]

Thank you so much for the advice!
by Joanne Kang 3I
Fri Oct 25, 2019 4:46 pm
Forum: Resonance Structures
Topic: Delocalized
Replies: 4
Views: 72

Delocalized

Can someone please explain what de-localized means?
by Joanne Kang 3I
Wed Oct 23, 2019 11:09 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.15
Replies: 3
Views: 58

1D.15

What are the principal and orbital angular momentum quantum numbers for each of the following orbitals: (a) 6p; (b) 3d; (c) 2p; (d) 5f?

Can someone please explain how to solve this
by Joanne Kang 3I
Mon Oct 21, 2019 12:24 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: What's the right equation?
Replies: 7
Views: 112

What's the right equation?

Is the right equation △p△m ≥(h/4π) or △p△m ≥(1/2)h???
Lavelle and the solutions manual say different things...
by Joanne Kang 3I
Mon Oct 21, 2019 12:18 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Focus 1B.25 & 27 Homework
Replies: 3
Views: 51

Re: Focus 1B.25 & 27 Homework

For 1B.27, the solutions manual is wrong. The answer should be 6.7x10^-34 m. This may clear things up for you
by Joanne Kang 3I
Fri Oct 18, 2019 9:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4s vs. 3d
Replies: 6
Views: 81

Re: 4s vs. 3d

Lavelle actually said that after the 4s state/orbital is occupied and the electron enters the 3rd orbital, then the 3d state is lower in energy than 4s
by Joanne Kang 3I
Fri Oct 18, 2019 9:02 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: building up principle
Replies: 5
Views: 60

Re: building up principle

It basically means that electrons fill orbitals in the lowest energies levels first before taking up higher energies. This is because atoms always want to be in the lowest energy state as possible.
by Joanne Kang 3I
Fri Oct 18, 2019 8:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Hund's Rule
Replies: 4
Views: 86

Hund's Rule

Can someone reiterate Hund's rule and summarize its main point/why it's important please?
by Joanne Kang 3I
Fri Oct 18, 2019 8:48 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg
Replies: 4
Views: 33

Heisenberg

What is main point of Heisenberg's equation?
by Joanne Kang 3I
Wed Oct 16, 2019 12:05 am
Forum: Properties of Light
Topic: 1A.11
Replies: 2
Views: 39

1A.11

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series or Lyman series, as shown in Fig. 1A.10). What is common to the lines within a series that makes grouping them together logical? Can someone please explain the ans...
by Joanne Kang 3I
Fri Oct 11, 2019 11:19 am
Forum: Properties of Light
Topic: Amplitude
Replies: 12
Views: 182

Re: Amplitude

Since amplitude is not included in the equations that were taught to us, I don't think we should worry about it. Like you said, the most important concept is that as wavelength goes down, frequency goes up and vice versa.
by Joanne Kang 3I
Fri Oct 11, 2019 11:12 am
Forum: Student Social/Study Group
Topic: Best Sessions
Replies: 12
Views: 191

Best Sessions

What are the best sessions to go to for getting extra practice outside of the textbook problems?
by Joanne Kang 3I
Thu Oct 10, 2019 2:51 pm
Forum: SI Units, Unit Conversions
Topic: Course Reader
Replies: 6
Views: 194

Course Reader

Is there a course reader for Lavelle’s class? If so, where can I get it?
by Joanne Kang 3I
Tue Oct 08, 2019 8:23 pm
Forum: Balancing Chemical Reactions
Topic: Chemical States
Replies: 3
Views: 98

Chemical States

When we write out a chemical equation, do we have to write their physical states like (l), (g), (aq) next to the molecules??
by Joanne Kang 3I
Tue Oct 08, 2019 3:00 pm
Forum: SI Units, Unit Conversions
Topic: Practice Problems?
Replies: 11
Views: 245

Practice Problems?

Are there practice problems for the fundamentals section? If so, where is it?
by Joanne Kang 3I
Fri Oct 04, 2019 10:00 am
Forum: SI Units, Unit Conversions
Topic: SI
Replies: 5
Views: 86

SI

Which SI units should we memorize for the test?
by Joanne Kang 3I
Tue Oct 01, 2019 9:52 pm
Forum: Significant Figures
Topic: General Rules to Help with Sig Figs
Replies: 18
Views: 453

Re: General Rules to Help with Sig Figs

0.00431 would be considered 3 sig figs, meaning the three zeros in front are insignificant.
For 4 and 5
ex. 50.00 and 5.000 x 10 has 4 sig figs
0.00501 and 5.01x10^2 has 3 sig figs
by Joanne Kang 3I
Tue Oct 01, 2019 9:43 pm
Forum: Significant Figures
Topic: E1 Sig Figs
Replies: 4
Views: 97

E1 Sig Figs

The question: The field of nanotechnology offers some intriguing possibilities, such as the creation of fibers one atom wide. Suppose you were able to string together 1.00 mol Ag atoms, each of radius 144 pm, into one of these fibers by encapsulating them in carbon nanotubes (see Chapter 7). How lon...
by Joanne Kang 3I
Tue Oct 01, 2019 5:28 pm
Forum: Empirical & Molecular Formulas
Topic: HW E17 part C
Replies: 5
Views: 115

Re: HW E17 part C

Yes. This is a trick question, so doing the stoichiometry for each molecule should reveal that they both convert to 1.22x10^4 moles.

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