Search found 34 matches
- Sat Mar 18, 2017 5:46 pm
- Forum: *Alcohols
- Topic: 2013 final Q6B
- Replies: 2
- Views: 1536
Re: 2013 final Q6B
Just remember the suffix to the functional groups: ie alcohol is -ol, carboxylic acid is -ic acid... etc., from the name you can identify the structure.
- Tue Mar 14, 2017 11:27 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Final 2013 Question 4b
- Replies: 1
- Views: 429
Final 2013 Question 4b
Can anyone help walk me through this problem?
- Tue Mar 14, 2017 11:25 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Final 2013 Question 4
- Replies: 1
- Views: 734
Final 2013 Question 4
For part A of question 4 on the 2013 final, can we also use Ecell = Ecello - 0.05916/n * logQ instead of Ecell = Ecello - RT/nF * lnQ ?
I get a slightly bigger answer when I use the Nernst equation with log in it than the one with ln.
I get a slightly bigger answer when I use the Nernst equation with log in it than the one with ln.
- Sun Mar 12, 2017 8:36 pm
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Cis & Trans
- Replies: 3
- Views: 734
Re: Cis & Trans
"E" is used in regards to a "trans" molecule where the priority molecule is on opposite sides. See my attachment for clarification!
- Thu Mar 09, 2017 5:40 pm
- Forum: *Alkenes
- Topic: Priority in Alkenes
- Replies: 2
- Views: 619
Re: Priority in Alkenes
Whichever element has the highest atomic # gets priority. These are the elements on the right and left sides, not horizontal and vertical. For example, in the photo I've attached below... - The first molecule is "Z" because the chlorine gets priority on the left, and the bromine gets prior...
- Sun Mar 05, 2017 11:56 pm
- Forum: *Alkanes
- Topic: Isopropyl vs Propyl [ENDORSED]
- Replies: 4
- Views: 23797
Re: Isopropyl vs Propyl [ENDORSED]
The substituent isopropyl has distinct "Y" shape, and the propyl substituent is just a jagged line of CH2CH2CH3.
In the attached picture, the first is the propyl substituent and the second is the isopropyl substituent.
In the attached picture, the first is the propyl substituent and the second is the isopropyl substituent.
- Sat Feb 25, 2017 12:02 am
- Forum: *Nucleophiles
- Topic: Course reader p. 82
- Replies: 2
- Views: 710
Re: Course reader p. 82
I like to think of the nucleophile as the area with the most e- density -- of course, this can be an element or a double/triple/etc bond.
- Fri Feb 24, 2017 11:57 pm
- Forum: *Electrophiles
- Topic: Bruincast Friday 2/24
- Replies: 5
- Views: 1350
Re: Bruincast Friday 2/24
Try waiting until Lecture 3's Bruin Cast comes out!
- Sun Feb 19, 2017 2:42 am
- Forum: Balancing Redox Reactions
- Topic: H+ and e-
- Replies: 4
- Views: 4583
Re: H+ and e-
The H + protons are to balance the H atoms in the equation and the electrons are used to balance the charge. For example, to balance this equation: 2e - + SeO 4 2- --> SeO 3 2- + H 2 O You will need to add 2 H + ions to the left to balance out the 2 H molecules in H 2 O. This will form: 2 H + + 2e -...
- Sun Feb 12, 2017 11:51 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2949084
- Tue Jan 31, 2017 11:07 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Prep quiz 1 #3
- Replies: 3
- Views: 765
Re: Prep quiz 1 #3
Work is not a state function.
Do I only use the volume values because it's an isothermal reaction?
Do I only use the volume values because it's an isothermal reaction?
- Tue Jan 31, 2017 10:42 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Prep quiz 1 #3
- Replies: 3
- Views: 765
Prep quiz 1 #3
Hello everyone, For the 3rd question for the prep quiz #1, "If 2.00 mol of an ideal gas at 300. K and 3.00 atm expands isothermally and reversibly from 6.00L to 18.00L and has a final pressure of 1.20atm, what is w, q and delta U?" Why do we use the equation w = -nRTln(V2/V1) and not w = -...
- Sun Jan 29, 2017 11:57 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Question about work
- Replies: 1
- Views: 426
Question about work
In the formula, w= -P(deltaV), why do we use the one with the negative sign and not the one without the negative sign?
- Sun Jan 22, 2017 11:42 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Unit conversions
- Replies: 2
- Views: 662
Re: Unit conversions
The practice quizzes in the back of the course reader also give great insight to how Dr. Lavelle will phrase his questions (units included).
- Mon Jul 25, 2016 4:39 pm
- Forum: Hybridization
- Topic: Hybridization [ENDORSED]
- Replies: 4
- Views: 1220
Re: Hybridization [ENDORSED]
Remember that hybridizations involve all areas of electron density , so that includes both bonds and lone pairs. The carbon in the ring structure of proline has 2 bonds between them, so it means that the carbon must have 2 pairs of lone pairs (to add up to 8 electrons total, to fulfill the octet rul...
- Wed Jul 20, 2016 12:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Workbook Problem #9 in Quiz 2 Prep 1
- Replies: 2
- Views: 506
Re: Workbook Problem #9 in Quiz 2 Prep 1
Your first step would be to find the molarity of BrCl by dividing moles over liters. (Also remember to balance the equation!)Then, multiply this value by 0.0812 to find how much BrCl was produced at equilibrium. Set up your ICE table and solve for x!
- Tue Jul 12, 2016 7:42 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape of molecules without a singular central atom
- Replies: 2
- Views: 1126
Re: Molecular Shape of molecules without a singular central
I think most of the time we will be dealing with a central atom, hence the AXE notation (where A = central atom, X = number of bonds and E = number of lone pairs). For your molecule of C 2 H 2 , I think you are missing a bond: it should be H-C≡C-H. Upon a quick google search, this molecule's shape i...
- Sat Jul 09, 2016 10:45 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Vs. electron [ENDORSED]
- Replies: 3
- Views: 983
Re: Molecular Vs. electron [ENDORSED]
Also keep in mind that the lone pairs do affect the overall shape of the compound: for example, the Lewis structure for H2O seems to be "linear," but because oxygen has 2 lone pairs, they push the hydrogens down, therefore creating the shape "bent." I think most of the time it'll...
- Mon Jul 04, 2016 11:04 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electronic configuration after Z=20
- Replies: 3
- Views: 1118
Re: Electronic configuration after Z=20
When we write the electron configuration for elements Z=20, the d-subshells are in front of the s-subshells because they are lower in energy.
- Sun Jul 03, 2016 3:02 pm
- Forum: Properties of Light
- Topic: Homework Question/ Midterm Question
- Replies: 2
- Views: 501
Re: Homework Question/ Midterm Question
I don't believe so. In the midterm review session with Yekan on Saturday, he mentioned that we should know the energy and wavelength differences of different types of radiation (ie: which type of radiation has the highest energy, etc).
- Wed Jun 29, 2016 7:58 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Math Question [ENDORSED]
- Replies: 1
- Views: 802
Re: Math Question [ENDORSED]
Remember to use parentheses!
Instead of typing in "1.53*10^(24) / 6.0221*10^(23)," you should enter it into your calculator as (1.53 * 10^(24)) / (6.0221*10^(23)) and you should get 2.54. Better yet, use the fraction function on your calculator if you don't want to type the parentheses.
Instead of typing in "1.53*10^(24) / 6.0221*10^(23)," you should enter it into your calculator as (1.53 * 10^(24)) / (6.0221*10^(23)) and you should get 2.54. Better yet, use the fraction function on your calculator if you don't want to type the parentheses.
- Fri Jun 24, 2016 6:31 pm
- Forum: Administrative Questions and Class Announcements
- Topic: When must the Preparatory Self-quizzes be turned-in?
- Replies: 3
- Views: 778
Re: When must the Preparatory Self-quizzes be turned-in?
It's calculated on our syllabus:
Quizzes (2 x 40 mins) 80 pts
Weekly Online Discussion (2 pt per week) 10 pts
Two 2hr Exams (2x 120 mins) 240 pts
Total 330 pts
Quizzes (2 x 40 mins) 80 pts
Weekly Online Discussion (2 pt per week) 10 pts
Two 2hr Exams (2x 120 mins) 240 pts
Total 330 pts
- Fri Jun 24, 2016 11:56 am
- Forum: General Science Questions
- Topic: Summer 2016 Chem Workbook
- Replies: 1
- Views: 560
Summer 2016 Chem Workbook
Hi all,
I am using an old coursereader for our chem class, so I don't have the workbook with the preparatory quizzes that are due before our in-class quizzes. Can anyone post pictures of both quizzes for me?
Thanks!!!
I am using an old coursereader for our chem class, so I don't have the workbook with the preparatory quizzes that are due before our in-class quizzes. Can anyone post pictures of both quizzes for me?
Thanks!!!
- Fri Jun 24, 2016 11:54 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra Question [ENDORSED]
- Replies: 3
- Views: 820
Re: Atomic Spectra Question [ENDORSED]
Well, when an electron transitions from a higher energy level to a lower energy level, it emits electromagnetic radiation.
Not sure if it is positive or negative energy... but you plug in positive energy into Bohr's Frequency equation (En= -(hR)/n^2).
Not sure if it is positive or negative energy... but you plug in positive energy into Bohr's Frequency equation (En= -(hR)/n^2).
- Thu Jun 23, 2016 5:43 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Fundamentals E Homework [ENDORSED]
- Replies: 2
- Views: 712
Re: Fundamentals E Homework [ENDORSED]
You can find the conversions on the back of the textbook. "pm," I believe, are picometers.
- Thu Jun 23, 2016 4:13 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Question [ENDORSED]
- Replies: 3
- Views: 825
Re: Photoelectric Effect Question [ENDORSED]
I got a solution! I used the photoelectric effect equation: E(kinetic) = E(photon) - E(threshold) And using E = (hc)/λ (combining E=hv and c=λv), plugging in 194 nm into λ (remember to convert!), and finally plugging in the threshold energy (7.22 * 10^(-19) J), you'll get the answer! E(kinetic) = E(...
- Wed Jun 22, 2016 10:39 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Question [ENDORSED]
- Replies: 3
- Views: 825
Re: Photoelectric Effect Question [ENDORSED]
Okay -- 7.22 * 10^(-19) J is correct for the above question!
But there is a part two...
"If molybdenum is irradiated with light of wavelength of 194 nm, what is the maximum possible kinetic energy of the emitted electrons?"
How would I proceed with this problem?
But there is a part two...
"If molybdenum is irradiated with light of wavelength of 194 nm, what is the maximum possible kinetic energy of the emitted electrons?"
How would I proceed with this problem?
- Wed Jun 22, 2016 10:30 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect Question [ENDORSED]
- Replies: 3
- Views: 825
Photoelectric Effect Question [ENDORSED]
Here is the problem I am stuck on: "Molybdenum metal must absorb radiation with a minimum frequency of 1.09 * 10^(15) s^(-1) before it can emit an electron from its surface. What is the minimum energy needed to produce this effect?" Would it be correct to use E=hv? I got an answer of E = 7...
- Fri Dec 04, 2015 12:08 pm
- Forum: Dipole Moments
- Topic: How do you find the "largest dipole moment"?
- Replies: 6
- Views: 91531
Re: How do you find the "largest dipole moment"?
How about HBr? And HI?
- Thu Dec 03, 2015 9:05 pm
- Forum: Dipole Moments
- Topic: How do you find the "largest dipole moment"?
- Replies: 6
- Views: 91531
How do you find the "largest dipole moment"?
This is question 3B on the 2014 Final exam:
Which of the following molecules has the largest dipole moment?
CO
NO
HI
HBr
HF
How do I find the dipole moments of these molecules, and how do I know which one is the "largest"?
Thanks!
Which of the following molecules has the largest dipole moment?
CO
NO
HI
HBr
HF
How do I find the dipole moments of these molecules, and how do I know which one is the "largest"?
Thanks!
- Wed Nov 25, 2015 11:23 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Video: Molecular Orbital
- Replies: 4
- Views: 13701
Video: Molecular Orbital
Molecular Orbital video which Jasmine Paraiso, Swan Ng, and I worked on off Drake's "Hotline Bling". Enjoy & ask questions!
Here the Youtube link for anyone having difficulty watching the video: https://youtu.be/w8hSnSN2cVA.
Here the Youtube link for anyone having difficulty watching the video: https://youtu.be/w8hSnSN2cVA.
- Sun Nov 01, 2015 9:47 am
- Forum: Hybridization
- Topic: pi and sigma bonds
- Replies: 2
- Views: 447
Re: pi and sigma bonds
A single bond: 1 sigma bond
A double bond: 1 sigma bond and 1 pi bond
A triple bond: 1 sigma bond and 2 pi bonds
A double bond: 1 sigma bond and 1 pi bond
A triple bond: 1 sigma bond and 2 pi bonds
- Sat Oct 31, 2015 11:59 pm
- Forum: Hybridization
- Topic: How do you find hybridization?
- Replies: 3
- Views: 1248
How do you find hybridization?
How would you find the hybridization of a benzene (C6H6)? I don't understand how to map out the energy levels, 2s, 2p, etc.
- Sat Oct 10, 2015 11:14 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Practice Quiz for Quiz 1
- Replies: 3
- Views: 693
Practice Quiz for Quiz 1
Hi everyone, Our first quiz for Chem 14A is next week, week 3, and I remember my TA saying something about completing a practice quiz before our actual quiz and turning it in the day. Does anyone know which practice quiz it is in our green workbook? There are a total of 3 quizzes in the workbook. Th...