Search found 88 matches

by Henri_de_Guzman_3L
Sat Dec 08, 2018 10:16 pm
Forum: Bronsted Acids & Bases
Topic: Base Strength
Replies: 4
Views: 44

Re: Base Strength

Morphine will accept a proton on the N atom. This is a very weak base. The conjugate acid of BrO- is BrOH which is a weak acid. This suggests that BrO- is a relatively strong base, stronger than morphine
by Henri_de_Guzman_3L
Sat Dec 08, 2018 10:14 pm
Forum: Bronsted Acids & Bases
Topic: Base Strength
Replies: 4
Views: 44

Re: Base Strength

You mean BrO-
by Henri_de_Guzman_3L
Sat Dec 08, 2018 10:14 pm
Forum: Bronsted Acids & Bases
Topic: Lewis vs Bronsted
Replies: 10
Views: 77

Re: Lewis vs Bronsted

Lewis Acids and Bases are electron pair acceptors and donors respectively.
Bronsted Acids and Bases are proton donors and acceptors respectively.
by Henri_de_Guzman_3L
Fri Dec 07, 2018 1:28 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: SO THERE ARE SPECIAL RULES FOR SIG FIGS IN pH THEN
Replies: 5
Views: 80

SO THERE ARE SPECIAL RULES FOR SIG FIGS IN pH THEN

Does anyone know if Dr. Lavelle gave instructions on doing sig figs in pH calculations? Apparently there is a special rule in chemistry. Each decimal place AFTER the decimal pointcounts as one sig fig. Everything to the LEFT of the decimal point does not count as a sig fig. For example: 7.3 has one ...
by Henri_de_Guzman_3L
Fri Dec 07, 2018 1:23 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Are all pH calculations done to 2 decimal places or do we use sig figs in pH calculations? [ENDORSED]
Replies: 2
Views: 43

Are all pH calculations done to 2 decimal places or do we use sig figs in pH calculations? [ENDORSED]

For example 6B.5c in the 7th edition textbook asks us to calculate the pH for 0.0092 M Ba(OH)2. This is 2 sig figs but the answer in the back gives 12.96. Should the answer instead be 13?
by Henri_de_Guzman_3L
Fri Dec 07, 2018 12:40 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 3 [ENDORSED]
Replies: 3
Views: 33

Re: 6B. 3 [ENDORSED]

This is how I did it and I got the correct answers. The phrasing of the question is terrible. You have to assume that the solution of 250 ml is DILUTED with water

20181207_003620.jpg
by Henri_de_Guzman_3L
Fri Dec 07, 2018 12:31 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 3 [ENDORSED]
Replies: 3
Views: 33

Re: 6B. 3 [ENDORSED]

I'm stuck on this too. I can get the right answer for part A but part B doesn't make any sense. Wouldn't the pH of either volume be the same??
by Henri_de_Guzman_3L
Fri Dec 07, 2018 12:08 am
Forum: Amphoteric Compounds
Topic: What makes As2O3 Amphoteric?
Replies: 2
Views: 44

Re: What makes As2O3 Amphoteric?

Aha, I might be getting Amphoteric and Amphiprotic mixed up. As2O3 is NOT Amphiprotic, as it can not donate an H+ ion. It IS Amphoteric because it can react with an acid (such as HCL) or with a base (such as NaOH) Am I correct in this logic? All amphiprotic substances are amphoteric but not all amph...
by Henri_de_Guzman_3L
Fri Dec 07, 2018 12:02 am
Forum: Amphoteric Compounds
Topic: What makes As2O3 Amphoteric?
Replies: 2
Views: 44

What makes As2O3 Amphoteric?

On one of the homework questions (I believe it was 6A.17 from the 7th edition) we had to classify As2O3 as basic, acidic, or amphoteric. I know the definition of amphoteric is that it reacts with both acids and bases. My question is how? here is the structure of As2O3 imgsrv.png I can see how it wou...
by Henri_de_Guzman_3L
Thu Dec 06, 2018 8:01 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 7
Views: 49

Re: pH formula?

We don't need to know how they're derived although reading through the textbook I feel it is helpful in understanding how they work.
by Henri_de_Guzman_3L
Thu Dec 06, 2018 10:22 am
Forum: Administrative Questions and Class Announcements
Topic: Will any kind soul please let me know what we went over in class yesterday? (Wednesday)
Replies: 2
Views: 54

Will any kind soul please let me know what we went over in class yesterday? (Wednesday)

I missed Wednesday's class 12/5 and I was just wondering if anyone could help out and let me know what Dr. Lavelle went over. He was scheduled to go over "only 3 pages" and was going to finish the syllabus. I'd appreciate any help!
by Henri_de_Guzman_3L
Thu Dec 06, 2018 10:21 am
Forum: Conjugate Acids & Bases
Topic: Will any kind soul please let me know what we went over in class yesterday? (Wednesday)
Replies: 1
Views: 25

Will any kind soul please let me know what we went over in class yesterday? (Wednesday)

I missed Wednesday's class 12/5 and I was just wondering if anyone could help out and let me know what Dr. Lavelle went over. He was scheduled to go over "only 3 pages" and was going to finish the syllabus. I'd appreciate any help!
by Henri_de_Guzman_3L
Thu Nov 29, 2018 8:21 pm
Forum: Hybridization
Topic: 2F.15 question 7th edition
Replies: 3
Views: 16

Re: 2F.15 question 7th edition

That makes perfect sense thank you!
by Henri_de_Guzman_3L
Thu Nov 29, 2018 8:21 pm
Forum: Hybridization
Topic: 2F.15 question 7th edition
Replies: 3
Views: 16

Re: 2F.15 question 7th edition

That makes perfect sense thank you!
by Henri_de_Guzman_3L
Thu Nov 29, 2018 7:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 7th edition 2E.1 mistake ?
Replies: 6
Views: 48

Re: 7th edition 2E.1 mistake ?

Got it! AX2E3 is linear with three equatorial lone pairs.
by Henri_de_Guzman_3L
Thu Nov 29, 2018 7:10 pm
Forum: Hybridization
Topic: 2F.15 question 7th edition
Replies: 3
Views: 16

2F.15 question 7th edition

So why does the bond angle increase as the s character of a hybrid orbital increase?
by Henri_de_Guzman_3L
Wed Nov 28, 2018 9:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 7th edition 2E.1 mistake ?
Replies: 6
Views: 48

7th edition 2E.1 mistake ?

2E.1 part b gives you a bond angle of 180 degrees (linear shape) and asks whether around the central atom there: must be, may be, or cannot be one or more lone pairs. I'm pretty sure the answer is cannot be one or more lone pairs. Isn't the only way you can have a 180 degree bond angle (linear shape...
by Henri_de_Guzman_3L
Wed Nov 28, 2018 6:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs and polarity
Replies: 1
Views: 21

Re: Lone pairs and polarity

SF6 has a perfectly symmetrical octahedral shape right? The charges therefore "cancel out."

SF4 is AX4E which is a seesaw shape. This is not symmetrical. The F atoms pull in one direction. See the table on page 113 in the 7th edition textbook for a clear diagram on shapes and polarity.
by Henri_de_Guzman_3L
Wed Nov 28, 2018 6:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Why is AX3E2 not trigonal planar?
Replies: 2
Views: 27

Why is AX3E2 not trigonal planar?

To me trigonal planar for AX3E2 would make more sense, putting the lone pairs on axial positions. This way they are 180 degrees apart from each other. Since lone pairs have the strongest repulsion wouldn't this be optimal? Why is it T-shaped instead?
by Henri_de_Guzman_3L
Sun Nov 25, 2018 6:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 3 material
Replies: 6
Views: 50

Test 3 material

Up to which topics will be on test 3, anyone know?
by Henri_de_Guzman_3L
Sun Nov 25, 2018 6:13 pm
Forum: Octet Exceptions
Topic: How do we know if an element can have an expanded octet?
Replies: 3
Views: 33

How do we know if an element can have an expanded octet?

I know it's period 3 elements and on but why? It's something to do with an available d orbital?
by Henri_de_Guzman_3L
Sun Nov 25, 2018 6:12 pm
Forum: Hybridization
Topic: Hybridization
Replies: 4
Views: 40

Re: Hybridization

Remember:
# of hybridized orbitals = # of regions of electron density
by Henri_de_Guzman_3L
Sun Nov 25, 2018 6:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent/Angular Shape
Replies: 4
Views: 43

Re: Bent/Angular Shape

They are the same, I've only heard of "bent" in my previous chem classes, I have never used angular. According to the book, they are the same
by Henri_de_Guzman_3L
Sun Nov 25, 2018 6:06 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
Replies: 4
Views: 30

Re: hydrogen bonding

Just remember that it only occurs between hydrogen, nitrogen, oxygen or fluorine atoms (H N O F). What is it? Take water molecules for example. 2 hydrogen atoms are bonded with one oxygen atom. The oxygen atoms, because of higher electronegativity, pull the electrons closer to it than the hydrogen a...
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:29 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Do we not need to know oxidation numbers for this class?
Replies: 2
Views: 47

Do we not need to know oxidation numbers for this class?

It seems like all we need to know is formal charge? Is it worth it to go back and learn oxidation numbers?
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:28 pm
Forum: Electronegativity
Topic: Is it best to memorize electronegativity?
Replies: 8
Views: 105

Is it best to memorize electronegativity?

If we don't "memorize" atom's electronegativity, is there a way to intuitively know what makes a polar vs nonpolar molecule?
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion posts grading (Anyone have a grade for this yet?)
Replies: 3
Views: 66

Discussion posts grading (Anyone have a grade for this yet?)

I haven't had any feedback yet on my chem community discussion posts in terms of a grade. How do I know my 3 weekly posts are being counted?
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:22 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 6
Views: 57

Re: Dipole Moments

It's a way to indicate the pull of electrons. It all depends on electronegativity. For example, O will pull electrons towards it in a C-O bond so this creates a dipole moment.
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AX2E3 shape
Replies: 2
Views: 41

Re: AX2E3 shape

lone pair-lone pair > lone pair-atom > atom-atom
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving Wednesday Class
Replies: 19
Views: 230

Re: Thanksgiving Wednesday Class

He hasn't officially announced either way but if we are ahead we will not have class. Basically to be determined.
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shapes
Replies: 3
Views: 28

Re: Molecular shapes

Here's my tip: DON'T memorize anything! Start by getting very familiar with Lewis Structures. Once you can do them in your sleep, get familiar with finding the VSEPR models (AXE formula) for these Lewis structures. This should be fairly easy if you're comfortable with doing Lewis structures. Once yo...
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:12 pm
Forum: SI Units, Unit Conversions
Topic: VSEPR model
Replies: 5
Views: 92

Re: VSEPR model

To me the model is very intuitive but the definition can be overwhelming. Basically VSEPR models follow the basic formula of AXE with a number subscript on the X and E. We regard A as the central atom. X is the number of bonds of with other atoms (VSEPR doesn't care if they're single, double, or tri...
by Henri_de_Guzman_3L
Thu Nov 15, 2018 7:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Writing VSEPR for (CH3)2Be
Replies: 1
Views: 16

Re: Writing VSEPR for (CH3)2Be

Hi Katelin, I believe you can use the VSEPR model in 2 instances here: One regarding the Be atom as the central atom (which would give you AX2, linear structure) and one for either of the carbon atoms as the central atom (this case giving you AX4, tetrahedral structure). The overall structure is lin...
by Henri_de_Guzman_3L
Mon Nov 05, 2018 2:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Is my bruin card a valid form of "photo ID?" [ENDORSED]
Replies: 1
Views: 65

Is my bruin card a valid form of "photo ID?" [ENDORSED]

For the midterm we have a to bring a photo ID, will my bruin card work?
by Henri_de_Guzman_3L
Mon Nov 05, 2018 1:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Is my bruin card a valid form of "photo ID?"
Replies: 1
Views: 70

Is my bruin card a valid form of "photo ID?"

For the midterm we have to bring a photo ID. Will my bruin card work?
by Henri_de_Guzman_3L
Mon Nov 05, 2018 1:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Community
Replies: 2
Views: 51

Re: Chemistry Community

I think the calculations are done automatically by the system so I think if you miss one week it automatically gives you a 0. If you had a valid excuse or reason talk to Dr. Lavelle or your TA
by Henri_de_Guzman_3L
Mon Nov 05, 2018 1:31 pm
Forum: Lewis Structures
Topic: SO2 Lewis Structure
Replies: 4
Views: 46

Re: SO2 Lewis Structure

I spoke to Dr. Lavelle after class today as I had drawn resonance structures to answer this question. I drew O-S=O <-> O=S-O with a lone pair of electrons on S.

O=S=O is BETTER because this gives every atom a 0 formal charge and S can use it's d orbitals to hold extra electrons in bonding.
by Henri_de_Guzman_3L
Mon Nov 05, 2018 1:13 pm
Forum: DeBroglie Equation
Topic: work function and frequency
Replies: 4
Views: 96

Re: work function and frequency

You would have to find the energy of the incoming photons. You would convert the wavelength of the elected electron into kinetic energy then add that to the work function. This gives you the energy of an incoming photon. Then you simply convert energy into frequency using E=hv
by Henri_de_Guzman_3L
Mon Nov 05, 2018 1:09 pm
Forum: Resonance Structures
Topic: Radicals
Replies: 11
Views: 118

Re: Radicals

A radical typically has an unpaired valence electron. A good example is the chlorine atom which has 7 valence electrons. You would draw this as Cl with 7 dots around it
by Henri_de_Guzman_3L
Mon Nov 05, 2018 1:06 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm Material
Replies: 3
Views: 69

Re: Midterm Material

We will not be going over polarity or electronegativity
by Henri_de_Guzman_3L
Fri Nov 02, 2018 5:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Scantron
Replies: 6
Views: 56

Re: Scantron

I THINK it'll be similar in format to the first 2 tests. 8 questions, just bring a pencil and non programmable calculator
by Henri_de_Guzman_3L
Fri Nov 02, 2018 5:46 pm
Forum: Lewis Structures
Topic: Do brackets go over cations or anions or either or both?
Replies: 3
Views: 47

Do brackets go over cations or anions or either or both?

Is there even a specific guideline or it doesn't really matter?

I am referring to [ ] these brackets. For example which is more correct?
[Na] Cl or Na [Cl] or [Na] [Cl] ? (Add charges and dots for electrons)
by Henri_de_Guzman_3L
Fri Nov 02, 2018 5:43 pm
Forum: Ionic & Covalent Bonds
Topic: 2A.5 7th edition
Replies: 5
Views: 55

Re: 2A.5 7th edition

You're welcome! I just learned in discussion today that it is the same case for Ag+ ion which sits right below it on the periodic table. Happy studying!
by Henri_de_Guzman_3L
Tue Oct 30, 2018 1:22 pm
Forum: Ionic & Covalent Bonds
Topic: 2A.5 7th edition
Replies: 5
Views: 55

Re: 2A.5 7th edition

Copper has a "half-filled" 4s subshell. It is a special case. Only 1 electron sits in it's 4s subshell while 10 electrons sit in it's 3d subshell. This is a special case. Therefore, Cu+ is [Ar] 3d^10
by Henri_de_Guzman_3L
Tue Oct 30, 2018 1:19 pm
Forum: Significant Figures
Topic: Exam
Replies: 6
Views: 260

Re: Exam

Dr. Lavelle has a great resource for sig figs on the class website. Here it is: https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf
by Henri_de_Guzman_3L
Tue Oct 30, 2018 1:17 pm
Forum: General Science Questions
Topic: Midterm studying
Replies: 10
Views: 228

Re: Midterm studying

I think for any Chemistry test, practice practice practice and then practice some more. Practice until the material becomes so easy that you can do it in your sleep. Try as many different problems as you can. Do all the problems in your textbook, try Khan Academy, there are practice problems here ht...
by Henri_de_Guzman_3L
Tue Oct 30, 2018 1:15 pm
Forum: General Science Questions
Topic: Khan Academy
Replies: 10
Views: 209

Re: Khan Academy

Khan Academy is great. I also find this website to be somewhat helpful and there are a few practice problems on here: https://chem.libretexts.org/
by Henri_de_Guzman_3L
Thu Oct 25, 2018 1:16 pm
Forum: Administrative Questions and Class Announcements
Topic: 0/70 homework grade on myucla
Replies: 2
Views: 118

0/70 homework grade on myucla

Our grades for exam 1 and homework were posted to my ucla. My homework grade is 0/70. I have turned in completed homework for all 3 weeks so far so I'm wondering if this is in error. Does anyone else have this as well? I'm very OCD so I'm wondering what's going on here haha.
by Henri_de_Guzman_3L
Thu Oct 25, 2018 1:06 pm
Forum: *Particle in a Box
Topic: Particle in a box (textbook) [ENDORSED]
Replies: 4
Views: 231

Re: Particle in a box (textbook) [ENDORSED]

Basically think of what a wavelength is. It is the distance from one "peak" to another "peak." Think of a wavelength in a "box." It is bounded on 2 sides right? Therefore only a certain wavelength can "fit" into this box. A bigger or smaller wavelength will be...
by Henri_de_Guzman_3L
Wed Oct 24, 2018 10:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Answers to module questions?
Replies: 2
Views: 64

Answers to module questions?

Is there a way to access these so we can know if we're getting the right answers or not?
by Henri_de_Guzman_3L
Wed Oct 24, 2018 9:18 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 7th edition 1B.27 [ENDORSED]
Replies: 3
Views: 131

Re: 7th edition 1B.27 [ENDORSED]

I was right all along then! Haha thank you so much
by Henri_de_Guzman_3L
Wed Oct 24, 2018 8:58 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Extra Practice Problems
Replies: 2
Views: 56

Extra Practice Problems

This is for anyone looking for extra practice. There are good 5 problems on this site that I think cover this topic thoroughly and make you think about its practical use. https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_The...
by Henri_de_Guzman_3L
Wed Oct 24, 2018 5:31 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 7th edition 1B.27 [ENDORSED]
Replies: 3
Views: 131

7th edition 1B.27 [ENDORSED]

This question gives the velocity of the bowling ball to be 5.00 +/- (plus or minus) 5.0 m/s. I plugged 5.0 m/s into the uncertainty formula and got the right answer. My question is why? The total uncertainty would be 10.0 m/s correct? This doesn't give me the correct answer though.
by Henri_de_Guzman_3L
Tue Oct 23, 2018 3:34 pm
Forum: Properties of Light
Topic: Atomic Spectra
Replies: 2
Views: 48

Re: Atomic Spectra

Yes this will be on the exam! To add on what has been replied to, this relates to hydrogen ONLY.
by Henri_de_Guzman_3L
Tue Oct 23, 2018 3:31 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Significance of XYZ to PDF orbitals
Replies: 6
Views: 104

Re: Significance of XYZ to PDF orbitals

I think it's just one way to distinguish between different locations in a given shell. It's like filling _ _ _ with electrons except we use X, Y, and Z
by Henri_de_Guzman_3L
Tue Oct 23, 2018 3:29 pm
Forum: Properties of Light
Topic: Is light in waves or photons?
Replies: 10
Views: 189

Re: Is light in waves or photons?

Think about it, we don't know the mass of a photon right? Also, use landa x v =c
by Henri_de_Guzman_3L
Tue Oct 23, 2018 3:28 pm
Forum: Properties of Light
Topic: Is light in waves or photons?
Replies: 10
Views: 189

Re: Is light in waves or photons?

For calculation purposes, use light as a wave (do not use De Broglie formula). Use E=hv when doing light calculations. However it DOES has light-wave duality. Hope that helps!
by Henri_de_Guzman_3L
Wed Oct 17, 2018 11:23 pm
Forum: Photoelectric Effect
Topic: Pre Assessment Module Question #13
Replies: 2
Views: 22

Pre Assessment Module Question #13

The question asks: Does the photoelectric experiment need to be done under a vacuum? I'm reading the text and I can't seem to find it here and I don't think Dr. Lavelle explicitly mentioned it in class. My instinct is to say yes.
by Henri_de_Guzman_3L
Sun Oct 14, 2018 12:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Is homework graded for correctness or completeness?
Replies: 5
Views: 141

Is homework graded for correctness or completeness?

I don't know if correctness is a word but my question is will the homeworks be graded if the answers are correct or do we just full credit if we did 7 problems, right or wrong?
by Henri_de_Guzman_3L
Sun Oct 14, 2018 12:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Grades??
Replies: 4
Views: 88

Grades??

Has anyone received any grades yet for homeworks or the test? I have not.
by Henri_de_Guzman_3L
Thu Oct 11, 2018 7:49 pm
Forum: Properties of Light
Topic: Problem 1A.9 (7th edition)
Replies: 5
Views: 29

Re: Problem 1A.9 (7th edition)

Isn't it dumb how we need E=hv to solve this problem, yet that isn't given until 1B? Am I tripping?
by Henri_de_Guzman_3L
Thu Oct 11, 2018 7:45 pm
Forum: Properties of Light
Topic: HW 1A.9 [ENDORSED]
Replies: 4
Views: 49

HW 1A.9 [ENDORSED]

For this problem, if I know the frequency and the wavelength, how do I find the energy of the photon? Is there a specific formula?
by Henri_de_Guzman_3L
Thu Oct 11, 2018 7:43 pm
Forum: Properties of Light
Topic: HW 1A.7
Replies: 2
Views: 51

Re: HW 1A.7

Yes I realized that! Problem solved, thank you!
by Henri_de_Guzman_3L
Thu Oct 11, 2018 1:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Where to find assignments
Replies: 5
Views: 79

Re: Where to find assignments

They're due every week during your discussion
by Henri_de_Guzman_3L
Thu Oct 11, 2018 1:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework and discussion grading?
Replies: 2
Views: 61

Homework and discussion grading?

I'm curious if anyone has gotten grades for the week 1 homework or discussion yet. Does anyone know when these will be up if not?
by Henri_de_Guzman_3L
Thu Oct 11, 2018 1:02 pm
Forum: Properties of Light
Topic: HW 1A.7
Replies: 2
Views: 51

HW 1A.7

For part b, I got 0.15 nm and the back of the book says 150. I'm confused??
by Henri_de_Guzman_3L
Thu Oct 11, 2018 10:49 am
Forum: Administrative Questions and Class Announcements
Topic: So can we do problems from Review of Chemistry for week 2 homework?
Replies: 4
Views: 59

So can we do problems from Review of Chemistry for week 2 homework?

I am turning in my homework tomorrow (Friday) and I saw a couple posts related to doing problems from Review of Chemistry for week 2 homework. Can anyone confirm this?
by Henri_de_Guzman_3L
Tue Oct 09, 2018 12:54 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: writing the formula of a molecule
Replies: 5
Views: 99

Re: writing the formula of a molecule

While Dr. Lavelle didn't explicitly state to do so, I think it would generally be a good idea in chem to know these anyway. They're not hard! I pasted them below, they're pretty intuitive:

1: mono-
2: di-
3: tri-
4: tetra-
5: penta-
6: hexa-
7: hepta-
8: octa-
9: nona-
10: deca-
by Henri_de_Guzman_3L
Tue Oct 09, 2018 12:50 pm
Forum: Molarity, Solutions, Dilutions
Topic: (Typo??) HW L.35 - 7th edition
Replies: 3
Views: 111

Re: (Typo??) HW L.35 - 7th edition

Thank you, I figured it's a total typo because otherwise it's impossible. I recommend to those with the same problem to just use Fe3Br8 as Ashish said.
by Henri_de_Guzman_3L
Thu Oct 04, 2018 10:35 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: writing the formula of a molecule
Replies: 5
Views: 99

Re: writing the formula of a molecule

A magnesium ion is Mg2+
Sulfate is SO4 2-
Together that makes MgSO4

The heptahydrate basically just adds H2O at the end. Hepta- is a prefix for 7.

So the official formula is MgSO4 . 7H2O
In chemistry, it's standard to add a little dot between the compound and the hydrate
by Henri_de_Guzman_3L
Thu Oct 04, 2018 10:29 pm
Forum: Limiting Reactant Calculations
Topic: Volume of Solution
Replies: 2
Views: 48

Re: Volume of Solution

So I'm assuming you converted grams of Na2CO3 to 39.84 mmoles of Na+. So now you have mmoles of Na+ in a volume of 250.0 ml and you want 2.15 mmol Na+. The mmoles of Na+ that you converted from the grams of Na2CO3 and the 250.0 ml are your "initial" mols and volume, respectively. Think of ...
by Henri_de_Guzman_3L
Thu Oct 04, 2018 10:21 pm
Forum: SI Units, Unit Conversions
Topic: Hecto as SI Unit [ENDORSED]
Replies: 4
Views: 31

Re: Hecto as SI Unit [ENDORSED]

By "never saw it," I mean it didn't pop up in the homework problems or examples but they did display it on the section reading covering SI units.
by Henri_de_Guzman_3L
Thu Oct 04, 2018 10:20 pm
Forum: SI Units, Unit Conversions
Topic: Hecto as SI Unit [ENDORSED]
Replies: 4
Views: 31

Re: Hecto as SI Unit [ENDORSED]

Hi Stephen, I think it would be safe to assume that the units Dr. Lavelle gave us were the only ones we'd be using for the class. Since he did not give us hecto-, I would assume that we would not need to use it for this class. However this does not mean that this is not an SI unit. As you mentioned ...
by Henri_de_Guzman_3L
Thu Oct 04, 2018 10:17 pm
Forum: SI Units, Unit Conversions
Topic: Reaction Stoichiometry Unit Conversion
Replies: 2
Views: 36

Re: Reaction Stoichiometry Unit Conversion

Hi Andrew, if you are referring to question L.5.a, it is totally ok to give the answer in either grams or kilograms. Prof. Lavelle even mentioned in class that both would be correct. The reason the textbook gives the answer in grams is think about it, 507.1 g Al versus 0.5071 kg Al. I think and the ...
by Henri_de_Guzman_3L
Thu Oct 04, 2018 10:10 pm
Forum: Molarity, Solutions, Dilutions
Topic: (Typo??) HW L.35 - 7th edition
Replies: 3
Views: 111

(Typo??) HW L.35 - 7th edition

Hi, so I was very stuck on the balancing part of this equation. I googled the answer and found links from Prof. Lavelle's chemistry community and I think there might be typo in my book. So my book asks the following question for L.35 "Sodium bromide, NaBr, which is used to produce AgBr for use ...
by Henri_de_Guzman_3L
Sun Sep 30, 2018 12:28 pm
Forum: Balancing Chemical Reactions
Topic: Question H21 (6th Edition)
Replies: 2
Views: 72

Re: Question H21 (6th Edition)

For the unbalanced equation we have: C10H15N + O2 --> CO2 + H2O + CH4N20 I started with balancing N first: 2C10H15N + O2 --> CO2 + H2O + CH4N20 Then H: 2C10H15N + O2 --> CO2 + 13H2O + CH4N20 Then C: 2C10H15N + O2 --> 19CO2 + 13H2O + CH4N20 Finally O: 2C10H15N + 26O2 --> 19CO2 + 13H2O + CH4N20
by Henri_de_Guzman_3L
Sat Sep 29, 2018 8:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Do we have to write out the question for homework?
Replies: 4
Views: 111

Do we have to write out the question for homework?

Like the subject asks. This is for Chem 14A Dr. Lavelle
by Henri_de_Guzman_3L
Fri Sep 28, 2018 12:02 pm
Forum: SI Units, Unit Conversions
Topic: How does grading for discussion posts work?
Replies: 73
Views: 1309

How does grading for discussion posts work?

Is there a minimum number of posts/replies to get full points?

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