Search found 40 matches

by Julieta Serobyan4D
Wed Nov 13, 2019 10:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VESPR Model of H2O
Replies: 12
Views: 34

Re: VESPR Model of H2O

Micah3J wrote:I was wondering about the example of the VSEPR Model of CO3 that we went over in lecture today. Does the double bond cause it to have any polarity?

Yes!! C has partially positive charge and O has partially negative charge.
by Julieta Serobyan4D
Wed Nov 13, 2019 10:54 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: H-bonding & Dipole-Dipole (Problem 3F.1)
Replies: 4
Views: 28

Re: H-bonding & Dipole-Dipole (Problem 3F.1)

Victoria Li 1L wrote:On homework problem 3F.1a and c, both molecules have all three intermolecular forces (dispersion forces, hydrogen bonding, & dipole-dipole). I was just wondering, if a molecule exhibits hydrogen bonding, does that mean they will also have dipole-dipole forces by default?

Yes, you are right!
by Julieta Serobyan4D
Wed Nov 13, 2019 10:52 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015435

Re: Post All Chemistry Jokes Here

How did the chemist survive the famine? He subsisted on titrations
by Julieta Serobyan4D
Wed Nov 13, 2019 10:52 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015435

Re: Post All Chemistry Jokes Here

Helium walks into a bar. The bartender says, "We don't serve noble gases here." Helium doesn't react
by Julieta Serobyan4D
Wed Nov 13, 2019 10:45 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015435

Re: Post All Chemistry Jokes Here

Q: How did the football cheerleader define hydrophobic on her chemistry exam? A: Fear of utility bills.
by Julieta Serobyan4D
Wed Nov 13, 2019 10:44 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015435

Re: Post All Chemistry Jokes Here

What is "HIJKLMNO"? H2O
by Julieta Serobyan4D
Wed Nov 13, 2019 10:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Class grading
Replies: 12
Views: 149

Re: Class grading

Tyler Angtuaco 1H wrote:Does anyone know the grading scale for final grades in this class?

Basically, he doesn't curve the test, but if the overall average is low, he might curve a little bit.
by Julieta Serobyan4D
Wed Nov 13, 2019 10:35 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: Determining Polarity
Replies: 5
Views: 27

Re: Determining Polarity

Leila_4E wrote:So, just to be sure, if it is a nonmetal + alkaline earth metal, it is polar molecule?

Yes, basically ionic bonds makes them polar
by Julieta Serobyan4D
Wed Nov 13, 2019 10:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Test #2
Replies: 16
Views: 88

Re: Test #2

My TA told me it's going to include VSEPR, IMF, polarity and bonding.
by Julieta Serobyan4D
Sun Nov 10, 2019 4:16 pm
Forum: General Science Questions
Topic: Midterms
Replies: 7
Views: 41

Re: Midterms

Celena Kim 3I wrote:Does anyone know what the next test will be covering?

I think it's going to include the stuff we have learned after the midterm, basically everything after 2D.
by Julieta Serobyan4D
Sun Nov 10, 2019 4:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 41

Re: Test 2

Mallika Chimpiri 3K wrote:Does anyone know which week Test 2 will be?

It's during week 8!
by Julieta Serobyan4D
Sun Nov 10, 2019 4:12 pm
Forum: Administrative Questions and Class Announcements
Topic: UA Workshops 11/11
Replies: 2
Views: 26

Re: UA Workshops 11/11

ayushibanerjee06 wrote:Will there still be UA workshops tomorrow?

I don't think so(
by Julieta Serobyan4D
Sun Nov 10, 2019 4:09 pm
Forum: General Science Questions
Topic: Test 2
Replies: 20
Views: 112

Re: Test 2

Do you know if the test is going to made by Professor Lavelle or the TAs?
by Julieta Serobyan4D
Sun Nov 10, 2019 4:07 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Magnetic Quantum numbers
Replies: 12
Views: 61

Re: Magnetic Quantum numbers

halle young 4A wrote:How do you determine the magnetic quantum number of an atom?

Magnetic quantum number depends on l. And if l=0, then it is 0 too.
by Julieta Serobyan4D
Sat Nov 02, 2019 2:33 am
Forum: Lewis Structures
Topic: central atom
Replies: 16
Views: 83

Re: central atom

Lauren Bui 1E wrote:When drawing a lewis structure, how do you determine which atom goes in the center?

If you do not know the electronegativity, you can basically count how many bonds each atom can form and then decide. For example, H in CH4 can form 1 bond, so it's logical to put C in the center
by Julieta Serobyan4D
Sat Nov 02, 2019 2:31 am
Forum: Properties of Electrons
Topic: Mass of an Electron
Replies: 14
Views: 92

Re: Mass of an Electron

Ashley Kao 1H wrote:In lecture and discussion, we learned that the mass of an electron is 9.109 x 10^-31 kg. Is this a set mass or can the mass of an electron vary from element to element?

No, electron's mass can't change . It's set .
by Julieta Serobyan4D
Sat Nov 02, 2019 2:29 am
Forum: Electronegativity
Topic: Ionic vs Covalent
Replies: 2
Views: 15

Re: Ionic vs Covalent

Yes, it's possible to get values in that range. In that case you have to do some other experiments or tests to find out the bonds. But for this class we don't have to know them
by Julieta Serobyan4D
Sat Nov 02, 2019 2:25 am
Forum: Ionic & Covalent Bonds
Topic: Anions and Cations
Replies: 9
Views: 44

Re: Anions and Cations

EthanPham_4D wrote:Why are anions larger than cations?

Anions have more electrons and it's harder for nucleus to pull them. So, the distance between the electrons and the nucleus increases.
by Julieta Serobyan4D
Sat Nov 02, 2019 12:45 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: General Question about Orbital... Filling..?
Replies: 5
Views: 20

Re: General Question about Orbital... Filling..?

Quick question, chem community. With the midterm around, just to make sure I won't get marked off for this, but in this case... If I ere writing the electron configuration of say, Titanium, would [Ar] 4s2, 3d2 be incorrect? Is [Ar] 3d2, 4s2 the only correct answer, or does the order of the orbitals...
by Julieta Serobyan4D
Fri Oct 25, 2019 5:51 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 1870

Re: Test 1 [ENDORSED]

505106414 wrote:Will any of the content from test 1 be on the midterm and/or test 2?

It's not going to be on test 2 . Test 2 is going to cover everything that we have learned after the midterm or the things that aren't covered by the midterm. And yes, the content of test 1 is going to be on the midterm.
by Julieta Serobyan4D
Fri Oct 25, 2019 5:48 pm
Forum: Ionic & Covalent Bonds
Topic: Bond length
Replies: 11
Views: 43

Re: Bond length

Kassidy Ford 1J wrote:Will bond length be given to us on tests or are we supposed to know bond lengths/assume resonance? Do you just base your lewis structure on the lowest formal charge?

We don't have to know the actual values, but we have to know how bond length affects the behavior of the molecule
by Julieta Serobyan4D
Fri Oct 25, 2019 5:40 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 16

Re: Electron Affinity

I haven't looked at the textbook yet, but I am pretty sure that first electron affinity is always negative . Well, the first electron that is taken up any atom other than a noble gas atoms or light atoms with half filled or full filled orbitals, releases energy. For the other types of atoms, they ar...
by Julieta Serobyan4D
Fri Oct 25, 2019 5:35 pm
Forum: Resonance Structures
Topic: Lewis Structures
Replies: 3
Views: 17

Re: Lewis Structures

There isn't any specific formula, so yeah you just have to draw every possible outcome. Just remember that pi bonds and sites are always good places to resonate. Also, sp3 hybridized carbons do not do resonance.
by Julieta Serobyan4D
Fri Oct 25, 2019 5:31 pm
Forum: Octet Exceptions
Topic: Formal Charge
Replies: 2
Views: 19

Re: Formal Charge

If I understood your question correctly, triple bonds are always more stable and therefore have more strength. You just have to satisfy the octet rule.
by Julieta Serobyan4D
Thu Oct 17, 2019 4:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: (N,l,m)
Replies: 2
Views: 26

Re: (N,l,m)

The quantum number m l tells us which orbital an electron is in. For example, if an electron is in an orbital in the 2p subshell: we know that the 2p-subshell (l=1) has 3 orbitals. These orbitals within 2p are denoted as m l =-1,0,1, which is based on the quantum number l. An electron in a 2p subsh...
by Julieta Serobyan4D
Thu Oct 17, 2019 4:32 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Atomic Radius
Replies: 18
Views: 84

Re: Atomic Radius

Atomic radius is usually given in a data booklet or just in the front page of the test.
by Julieta Serobyan4D
Thu Oct 17, 2019 4:26 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: how to express answer
Replies: 6
Views: 20

Re: how to express answer

I think equal sign would be fine in our situation.
by Julieta Serobyan4D
Thu Oct 17, 2019 4:22 pm
Forum: Quantum Numbers and The H-Atom
Topic: (N,l,m)
Replies: 2
Views: 26

(N,l,m)

Hello everyone!!! Can someone tell me what is m as a quantum number and how we can use its value to determine how the electron spins? I mean for example if it's -1, what does it represent?
by Julieta Serobyan4D
Thu Oct 17, 2019 4:09 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Heisenberg's Indeterminacy Equation
Replies: 3
Views: 21

Re: Heisenberg's Indeterminacy Equation

Yes! And as it is stated in our book: "Heisenberg's Uncertainty Principle states that the more precisely the position of the particle is known, the more uncertain the momentum is and vice versa." This is just an additional helpful information.
by Julieta Serobyan4D
Thu Oct 17, 2019 4:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Wavelength to Series/ Wave type
Replies: 2
Views: 27

Re: Wavelength to Series/ Wave type

As Alexis mentioned,Lyman and Balmer uncovered set of lines. Later Bohr found that that lines were electron transitions. Lyman series correspond to an electron going back to the ground state of the hydrogen atom, which is n=1, and Balmer series correspond to transitions down to n=2, which means visi...
by Julieta Serobyan4D
Sun Oct 13, 2019 4:29 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Best Way To Study?
Replies: 53
Views: 202

Re: Best Way To Study?

I definitely would suggest watching the modules and doing the pre and post assessments)
by Julieta Serobyan4D
Sun Oct 13, 2019 4:27 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015435

Re: Post All Chemistry Jokes Here

Did you hear about oxygen’s date with potassium?
It went OK

This one is the best
by Julieta Serobyan4D
Sun Oct 13, 2019 4:20 pm
Forum: Photoelectric Effect
Topic: Video Modules
Replies: 7
Views: 29

Re: Video Modules

Yeah, I always do that and after that I only try to concentrate on the parts that were not clear for me
by Julieta Serobyan4D
Sun Oct 13, 2019 4:16 pm
Forum: Properties of Light
Topic: Homework Question 1A.7
Replies: 2
Views: 25

Re: Homework Question 1A.7

Because one nanometer equals to 1×10-9 m, you have to divide your answer by it
For example, if it's 3.6×10-7 m, then you divide it by 1×10-9m, and the result will be 3.6×10^2 nm= 360 nm.

Hope this is clear!
by Julieta Serobyan4D
Sun Oct 13, 2019 3:59 pm
Forum: Properties of Light
Topic: SI units and wavelength
Replies: 6
Views: 19

Re: SI units and wavelength

Metre(m)
by Julieta Serobyan4D
Thu Oct 03, 2019 12:11 am
Forum: Empirical & Molecular Formulas
Topic: Naming Molecular Compounds
Replies: 6
Views: 40

Re: Naming Molecular Compounds

I am a little confused as to how to name compounds. I understand simple ones such as molecular compounds, but I can't seem to remember how to name compounds such as in H.25, when it asks to "name the different phosphorus oxides". Hey!!! I will advise you to read the corresponding sections...
by Julieta Serobyan4D
Wed Oct 02, 2019 11:59 pm
Forum: Limiting Reactant Calculations
Topic: Fundamentals M9 Part B
Replies: 2
Views: 66

Re: Fundamentals M9 Part B

Yes, you calculated the mass correctly. So 0.04 moles of Cu(NO3)2 would react with 0.05/2 = 0.0025 moles of NaOH, thus making NaOH the limiting reactant. With the balanced equation, you will see that the 0.05 moles of NaOH used up in the equation would produce 0.025 moles of Cu(OH)2. I hope this hel...
by Julieta Serobyan4D
Wed Oct 02, 2019 11:39 pm
Forum: Student Social/Study Group
Topic: Final Jitters
Replies: 61
Views: 18467

Re: Final Jitters

I usually listen to music before the exam and try not to think about it. Also, if I know the material well, I am not that nervous. So, yeah practising does help.
by Julieta Serobyan4D
Wed Oct 02, 2019 11:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 117
Views: 1687

Re: Advice from a Medical Student - Part II [ENDORSED]

Hi!!! Thank you so much for your advice. It's still confusing for me, but I hope it will get better.
by Julieta Serobyan4D
Wed Oct 02, 2019 10:59 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs
Replies: 18
Views: 134

Re: Sig figs

Do we apply Sig Figs after every calculation or only to the end result? I am not sure, but I usually do it at the end cause your result can be inaccurate, if you don't have enough sig.figs. I round up to 4 significant figures after each question and in the end round to the least sig.figs available ...

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