Search found 71 matches

by Deena Doan 2F
Thu Feb 20, 2020 11:08 pm
Forum: Student Social/Study Group
Topic: What Song Was Playing During Lecture?
Replies: 1
Views: 9

Re: What Song Was Playing During Lecture?

I'm pretty sure the song is "Whatever It Takes" by Imagine Dragons!
by Deena Doan 2F
Tue Feb 11, 2020 9:35 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 4H.5
Replies: 4
Views: 14

4H.5

4H.5 Which substance in each of the following pairs would you expect to have the higher standard molar entropy at 298 K and 1 bar? Explain your reasoning. (a) Iodine vapor or bromine vapor; (b) the two liquids cyclopentane and 1-pentene (see structures); (c) ethene (ethylene) or an equivalent mass o...
by Deena Doan 2F
Tue Feb 11, 2020 6:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.1 Part B
Replies: 1
Views: 9

4D.1 Part B

4D.1 Carbon disulfide can be prepared from coke (an impure form of carbon) and elemental sulfur: 4 C(s) + S8(s) -> 4 CS2(l) delta H° = 358.8 kJ Calculate the heat absorbed in the reaction of 197 g of carbon with an excess of sulfur. Can someone walk me through this and break it down conceptually?
by Deena Doan 2F
Tue Feb 11, 2020 6:11 pm
Forum: Phase Changes & Related Calculations
Topic: 4C.11
Replies: 2
Views: 19

4C.11

4C.11 How much heat is needed to convert 80.0 g of ice at 0.0 8C into liquid water at 20.0 8C (see Tables 4A.2 and 4C.1)?

Can someone explain this problem to me?
by Deena Doan 2F
Tue Feb 11, 2020 3:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A.7
Replies: 4
Views: 24

4A.7

(a) Calculate the heat that must be supplied to a copper kettle of mass 400.0 g containing 300.0 g of water to raise its temperature from 20.0 C to the boiling point of water, 100.0 C. (b) What percentage of the heat is used to raise the temperature of the water? (See Table 4A.2.) How do I solve this?
by Deena Doan 2F
Tue Feb 04, 2020 2:08 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Missing Notes
Replies: 2
Views: 18

Re: Missing Notes

Knowing both delta u or delta h and delta s of a system provides info on how the system will change
by Deena Doan 2F
Tue Feb 04, 2020 2:07 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed vs isolated
Replies: 14
Views: 41

closed vs isolated

Can someone explain the difference between a closed and isolated system?
by Deena Doan 2F
Sun Feb 02, 2020 4:57 pm
Forum: Student Social/Study Group
Topic: Any Worksheets from UA/TA/etc?
Replies: 14
Views: 151

Re: Any Worksheets from UA/TA/etc?

Some UA's post their worksheets on Chem Community, so you can probably search up worksheets or review to find them!
by Deena Doan 2F
Sun Feb 02, 2020 4:54 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Three Methods
Replies: 3
Views: 25

Three Methods

How do I know which method to use? Are there like key words/terms that will help me determine which method to use when it comes to solving the problem?
by Deena Doan 2F
Sun Feb 02, 2020 2:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 4 Friday Lecture
Replies: 4
Views: 32

Re: Week 4 Friday Lecture

Yeah, I can! What's your email?
by Deena Doan 2F
Tue Jan 21, 2020 6:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading of Tests
Replies: 18
Views: 92

Re: Grading of Tests

Most times, you do get partial credit if it makes sense. But, it also depends on the grader.
by Deena Doan 2F
Tue Jan 21, 2020 6:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.3
Replies: 1
Views: 30

6D.3

6D.3 (a) When the pH of 0.10 m HClO2(aq) was measured, it was found to be 1.2. What are the values of Ka and pKa of chlorous acid? (b) The pH of a 0.10 m propylamine, C3H7NH2, aqueous solution was measured as 11.86. What are the values of Kb and pKb of propylamine? How do you get the concentration o...
by Deena Doan 2F
Tue Jan 21, 2020 4:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5I.33
Replies: 1
Views: 17

5I.33

5I.33 A sample of ammonium carbamate, NH4(NH2CO2), of mass 25.0 g was placed in an evacuated flask of volume 0.250 L and kept at 25 8C. At equilibrium, 17.4 mg of CO2 was present. What is the value of Kc for the decomposition of ammonium carbamate into ammonia and carbon dioxide? The reaction is NH4...
by Deena Doan 2F
Tue Jan 21, 2020 1:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 51.13 Part C
Replies: 1
Views: 15

51.13 Part C

5I.13 (a) In an experiment, 2.0 mmol Cl2(g) was sealed into a reaction vessel of volume 2.0 L and heated to 1000. K to study its dissociation into Cl atoms. Use the information in Table 5G.2 to calculate the equilibrium composition of the mixture. (b) If 2.0 mmol F2 was placed into the reaction vess...
by Deena Doan 2F
Tue Jan 21, 2020 12:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: partial pressure vs concentrations
Replies: 3
Views: 7

partial pressure vs concentrations

When a problem is asking to write an expression for K, how do I know whether to use concentration or partial pressure?
by Deena Doan 2F
Sun Jan 12, 2020 11:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q
Replies: 6
Views: 18

K and Q

I know that they are solved the same way but what is the difference between solving for K and solving for Q?
by Deena Doan 2F
Sun Jan 12, 2020 11:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homogenous Equilibrium
Replies: 13
Views: 30

Re: Homogenous Equilibrium

it's when all reactants and products are in the same phase.
by Deena Doan 2F
Sun Jan 12, 2020 11:39 pm
Forum: Ideal Gases
Topic: ICE Table
Replies: 11
Views: 55

ICE Table

How do you use an ICE table?
by Deena Doan 2F
Sun Jan 12, 2020 11:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K's
Replies: 3
Views: 17

K's

What is the difference between Kc and Kp?
by Deena Doan 2F
Thu Jan 09, 2020 1:19 pm
Forum: Student Social/Study Group
Topic: Chemistry Community
Replies: 8
Views: 505

Re: Chemistry Community

I'm pretty sure they count at the end, but it might depend on your TA.
by Deena Doan 2F
Sat Dec 07, 2019 10:36 pm
Forum: Bronsted Acids & Bases
Topic: Amphoteric
Replies: 2
Views: 40

Re: Amphoteric

You have to draw it out to figure out where the lone pairs are.
by Deena Doan 2F
Sat Dec 07, 2019 10:32 pm
Forum: Naming
Topic: Numerical Prefixes
Replies: 2
Views: 15

Re: Numerical Prefixes

You use bis, tris, etc when it comes to en and dien and edta.
by Deena Doan 2F
Sat Dec 07, 2019 6:30 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH sig figs
Replies: 11
Views: 70

pH sig figs

Do sig figs only count after the decimal when it comes to pH?
by Deena Doan 2F
Thu Dec 05, 2019 6:14 pm
Forum: Naming
Topic: Name --> formula
Replies: 2
Views: 19

Re: Name --> formula

I'm pretty sure both forms are acceptable, but I would probably do it alphabetically just in case.
by Deena Doan 2F
Thu Dec 05, 2019 6:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Polarity
Replies: 2
Views: 21

Re: Determining Polarity

it's polar
by Deena Doan 2F
Sun Dec 01, 2019 7:37 pm
Forum: Naming
Topic: hacks
Replies: 2
Views: 69

hacks

Does anyone have a good way of memorizing the order of naming?
by Deena Doan 2F
Sun Dec 01, 2019 7:32 pm
Forum: Student Social/Study Group
Topic: Final Studying
Replies: 8
Views: 41

Re: Final Studying

The organic chemistry tutor is really good at explaining concepts.
by Deena Doan 2F
Sun Dec 01, 2019 7:29 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 5
Views: 51

Re: Cisplatin

There is a possibility we might have to know the structure of it as well because I think I read it somewhere on Bruinwalk.
by Deena Doan 2F
Sun Dec 01, 2019 5:12 pm
Forum: Student Social/Study Group
Topic: final
Replies: 4
Views: 36

final

Does anyone know what topics will be strongly emphasized on the final?
by Deena Doan 2F
Sun Dec 01, 2019 4:04 pm
Forum: Student Social/Study Group
Topic: readings
Replies: 13
Views: 130

Re: readings

I would read the sections that the homework problems are from. I think sections are also listed on the syllabus and the outlines. For studying, I recommend doing the homework problems and Youtube videos for extra practice!
by Deena Doan 2F
Sun Nov 24, 2019 11:07 pm
Forum: Student Social/Study Group
Topic: Any tips on how to catch up in this class?
Replies: 16
Views: 86

Re: Any tips on how to catch up in this class?

Youtube videos are super helpful and so are the step-up sessions! The UA's are really good at explaining concepts and they usually go through practice problems as well.
by Deena Doan 2F
Sun Nov 24, 2019 11:02 pm
Forum: Hybridization
Topic: octet expansion
Replies: 1
Views: 14

Re: octet expansion

Yes. Typically, elements in period 3 and above are able to have an expanded octet.
by Deena Doan 2F
Sun Nov 24, 2019 10:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7831
Views: 1087926

Re: Post All Chemistry Jokes Here

I'm sad. All of the good chemistry jokes argon :(
by Deena Doan 2F
Sun Nov 24, 2019 10:52 pm
Forum: Student Social/Study Group
Topic: test 2
Replies: 2
Views: 31

test 2

When will test 2 scores be out on myucla? Are we getting our tests back this week?
by Deena Doan 2F
Sun Nov 24, 2019 10:50 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 4
Views: 27

Ligands

What exactly is a ligand?
by Deena Doan 2F
Mon Nov 18, 2019 12:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 2
Views: 28

Re: VSEPR

valence shell electron pair repulsion model
by Deena Doan 2F
Sun Nov 17, 2019 5:31 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: 3F.3
Replies: 1
Views: 19

3F.3

Can someone explain this problem to me?

3F.3 For which of the following molecules will dipole–dipole interactions be important: (a) CH4; (b) CH3Cl; (c) CH2Cl2; (d) CHCl3; (e) CCl4?
by Deena Doan 2F
Sun Nov 17, 2019 5:26 pm
Forum: Student Social/Study Group
Topic: test 2
Replies: 8
Views: 49

Re: test 2

Also, does anyone know how many questions will be on the test?
by Deena Doan 2F
Sun Nov 17, 2019 5:12 pm
Forum: Student Social/Study Group
Topic: test 2
Replies: 8
Views: 49

test 2

Does anyone know how many points test 2 will be worth?
by Deena Doan 2F
Sun Nov 10, 2019 7:55 pm
Forum: Student Social/Study Group
Topic: chem 14b + cehm14bl
Replies: 9
Views: 66

chem 14b + cehm14bl

Hi,
Does anyone know if it is better to take Chem 14B and Chem 14BL together or Chem14C and Chem14BL together? Or does it not really matter?
by Deena Doan 2F
Sun Nov 10, 2019 7:51 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizability
Replies: 2
Views: 22

polarizability

Hi,
How can I use the periodic table to determine whether one element has higher polarizability compared to another element?
by Deena Doan 2F
Fri Nov 08, 2019 9:40 pm
Forum: Student Social/Study Group
Topic: midterm grades
Replies: 8
Views: 77

midterm grades

Will we be getting our tests back in our discussion section next week?
by Deena Doan 2F
Wed Nov 06, 2019 11:38 pm
Forum: Quantum Numbers and The H-Atom
Topic: Rydberg equation
Replies: 9
Views: 81

Re: Rydberg equation

It's preferred because it is easier to understand conceptually with the way he taught us in class.
by Deena Doan 2F
Wed Nov 06, 2019 11:34 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7831
Views: 1087926

Re: Post All Chemistry Jokes Here

So... when's the midterm?
by Deena Doan 2F
Sun Nov 03, 2019 11:19 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: rydberg equation
Replies: 2
Views: 34

rydberg equation

Hi,
Are we allowed to actually use Rydbreg's equation or do we have to solve these types of problems the way Lavelle taught us in class?
by Deena Doan 2F
Sun Nov 03, 2019 6:19 pm
Forum: Lewis Structures
Topic: lowest energy
Replies: 5
Views: 29

lowest energy

Hi,
What does it mean when it says to draw the lowest energy lewis structure?
by Deena Doan 2F
Sun Nov 03, 2019 6:12 pm
Forum: Lewis Structures
Topic: formal charge
Replies: 6
Views: 27

formal charge

Hi,
Does anyone know we have to use formal charge to check every lewis structure diagram we do on the midterm?
by Deena Doan 2F
Sun Nov 03, 2019 3:16 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1B.26
Replies: 4
Views: 54

Re: 1B.26

it's 10 m/s because it's a range from -5 to 5 m/s
by Deena Doan 2F
Sun Nov 03, 2019 3:01 pm
Forum: *Shrodinger Equation
Topic: Review
Replies: 4
Views: 70

Re: Review

The TA's and UA's typically have a list of topics they are going to go over and they go over the concepts while including practice problems as well. They're very helpful! Highly recommend.
by Deena Doan 2F
Sun Oct 27, 2019 11:52 pm
Forum: Administrative Questions and Class Announcements
Topic: HW 4
Replies: 2
Views: 25

Re: HW 4

I think it can be from both chemical bonds and the quantum world, but I would suggest emailing your TA just to make sure.
by Deena Doan 2F
Sun Oct 27, 2019 11:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E #13
Replies: 3
Views: 48

1E #13

How come the electron configuration for tungsten is [Xe]4f14 5d4 6s2 and not [Xe]4f14 5d5 6s1? Why didn't it follow the same rule as silver did?
by Deena Doan 2F
Sun Oct 27, 2019 11:44 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Midterm
Replies: 5
Views: 43

Re: Midterm

Hi! There is also this Youtuber called Tyler Dewit who has a video about electron configurations that is very helpful as well!
by Deena Doan 2F
Sun Oct 27, 2019 3:05 pm
Forum: Ionic & Covalent Bonds
Topic: Week 5 HW
Replies: 4
Views: 56

Week 5 HW

Hi,
Is this week's homework on just chemical bonds or can it also be from the quantum world?
by Deena Doan 2F
Sat Oct 26, 2019 5:56 pm
Forum: Ionic & Covalent Bonds
Topic: + and - ions
Replies: 3
Views: 61

Re: + and - ions

1) move left
2) move right
3) If it has a positive charge (aka a cation), it loses an electron.
4) If it has a negative charge (aka an anion), it gains an electron.
by Deena Doan 2F
Sun Oct 20, 2019 11:25 pm
Forum: Trends in The Periodic Table
Topic: memorization
Replies: 3
Views: 38

memorization

Hi,
Does anyone have any tricks or recommendations to help memorize the trends in the periodic table and also the characteristics of nonmetals/metals/metalloids?
by Deena Doan 2F
Sun Oct 20, 2019 11:08 pm
Forum: Student Social/Study Group
Topic: Midterm
Replies: 17
Views: 153

Midterm

Does anyone know if the Fundamentals section is going to be on our midterm?
by Deena Doan 2F
Sun Oct 20, 2019 11:00 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: spin
Replies: 3
Views: 33

spin

Hi,
Why can't there be parallel spins? Also, how do you know whether to start it up or down for the spins?
by Deena Doan 2F
Sun Oct 20, 2019 4:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 8
Views: 67

Orbitals

Hi,
In class, Lavelle went over some examples for the orbitals and he did Scandium as an example, but I am still a little confused on how why it is [Ar] 3d1, 4s2 and not the other way around.
by Deena Doan 2F
Sun Oct 20, 2019 4:53 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Advice for studying
Replies: 58
Views: 548

Re: Advice for studying

Hi! I definitely recommend everything else everyone has said so far! For me, what works the best is doing everything he assigns and joining study groups! They are so helpful and collaborating with other students makes it easier to understand. I also watch Youtube videos; there is this one guy named ...
by Deena Doan 2F
Sun Oct 13, 2019 11:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: #1E 5
Replies: 1
Views: 41

#1E 5

Hi, Can someone explain why part a is false? I read the solutions manual, but I am still a little bit confused. Thank you! Which of the following statements are true for many-elec- tron atoms? If false, explain why. (a) The effective nuclear charge Zeffe is independent of the number of electrons pre...
by Deena Doan 2F
Sun Oct 13, 2019 10:04 pm
Forum: *Black Body Radiation
Topic: Will this concept be tested
Replies: 8
Views: 454

Re: Will this concept be tested

No, it won't be tested.
by Deena Doan 2F
Sun Oct 13, 2019 10:00 pm
Forum: DeBroglie Equation
Topic: wavelike vs particle-like
Replies: 2
Views: 39

wavelike vs particle-like

Hi,
Can someone explain the difference between these two? Like what does it mean if something has wavelike properties but not particle-like and vice versa?
by Deena Doan 2F
Sun Oct 13, 2019 9:52 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1B #25
Replies: 1
Views: 44

1B #25

Hi,
Can someone please explain this problem to me? I don't understand it.

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.

Thank you!
by Deena Doan 2F
Sun Oct 13, 2019 9:38 pm
Forum: Properties of Light
Topic: 1B #5
Replies: 1
Views: 21

1B #5

I was just wondering if he expected us to know the constant in this problem or will he give it to us on tests?
by Deena Doan 2F
Sun Oct 06, 2019 4:18 pm
Forum: Empirical & Molecular Formulas
Topic: Polyatomic ions
Replies: 2
Views: 40

Re: Polyatomic ions

I'm not sure what exactly we have to know, but there is a table on F30 that has some common ones listed so I would probably want to know those.
by Deena Doan 2F
Sun Oct 06, 2019 2:18 pm
Forum: Significant Figures
Topic: Significant Figure numbers
Replies: 2
Views: 25

Re: Significant Figure numbers

it's the least amount of sigfigs that matter
by Deena Doan 2F
Sun Oct 06, 2019 2:16 pm
Forum: SI Units, Unit Conversions
Topic: Homework Vs. Test
Replies: 3
Views: 68

Re: Homework Vs. Test

Hi,
I'm pretty sure he is going to give us the formula, but I would brush up on the formulas for some basic compounds like nitric acid, etc just in case.
by Deena Doan 2F
Sun Oct 06, 2019 10:26 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: homework e9
Replies: 1
Views: 47

homework e9

Hi,
Can someone walk me through on finding the formula for magnesium sulfate heptahydrate and why 7 H2O is a part of the formula mass?
by Deena Doan 2F
Sun Oct 06, 2019 10:15 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Naming Formulas
Replies: 3
Views: 50

Naming Formulas

Hi, does anyone know if he expects us to know how to write formulas/compounds on the test? Was just wondering because some of the homework problems asked us to do so.

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