Search found 56 matches
- Sat Nov 13, 2021 8:21 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: calorimeter
- Replies: 3
- Views: 353
calorimeter
A constant‑volume calorimeter was calibrated by carrying out a reaction known to release 2.22 kJ of heat in 0.300 L of solution in the calorimeter (q=−2.22 kJ) , resulting in a temperature rise of 3.52 ∘C . In a subsequent experiment, 150.0 mL of 0.30 M HClO2(aq) and 150.0 mL of 0.30 M NaOH(aq) were...
- Fri Dec 11, 2020 8:29 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability and Polarizing Power
- Replies: 7
- Views: 530
Re: Polarizability and Polarizing Power
For atoms that are more polarizable, the bigger the atom is = the more polarizable. I like to remember this by thinking of an analogy where I'm trying to pop balloons with a dart. The bigger the balloon, the more likely I'll be when I throw a dart to pop it (influence its e- cloud). For polarizing ...
- Fri Dec 11, 2020 8:28 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Textbook Question 6B.1
- Replies: 4
- Views: 229
Re: Textbook Question 6B.1
Hello! Why is -log(x) the same as the original pH? I thought it would be the difference between pH1 and pH2. Thank you! Hi! So, the whole thing about pH is that it's the -log of the concentration of H + . Like Lavelle said in lecture, the "p" means that you take the -log. For example, pK ...
- Sun Dec 06, 2020 4:29 pm
- Forum: Dipole Moments
- Topic: Polarity from Shape
- Replies: 12
- Views: 681
Re: Polarity from Shape
Brendan Duong 1I wrote:MichaelMendozaD1F wrote:are ALL bent molecules polar?
Yes I believe all bent molecules are polar. The shape makes it so that dipoles can never cancel
thank you ! I appreciate the response!
- Sun Dec 06, 2020 4:28 pm
- Forum: Lewis Structures
- Topic: Most Stable Structure
- Replies: 23
- Views: 3494
Re: Most Stable Structure
Moura Girgis 1D wrote:MichaelMendozaD1F wrote:is most "stable" the same as most likely or favorable? I believe they are synonymous in these types of problems but I just want to make sure.
yes, more stable lewis structures also tend to be those with the lower formal charge, so they are more favorable .
thank you for the response !
- Sun Dec 06, 2020 4:11 pm
- Forum: Naming
- Topic: Sapling Q1
- Replies: 20
- Views: 903
Re: Sapling Q1
so would amine have two m's?
- Fri Dec 04, 2020 3:59 pm
- Forum: Lewis Structures
- Topic: Most Stable Structure
- Replies: 23
- Views: 3494
Re: Most Stable Structure
is most "stable" the same as most likely or favorable? I believe they are synonymous in these types of problems but I just want to make sure.
- Fri Dec 04, 2020 3:57 pm
- Forum: Hybridization
- Topic: How to simply determine hybridization
- Replies: 27
- Views: 10651
Re: How to simply determine hybridization
Here is a helpful little way to remember, but I believe it is also realllyyyy important to understand why the hybridization occurs rather then memorize the numbers. https://d3i71xaburhd42.cloudfront.net/ac73a46dc482862c4baa12b73f648f3dd3fa5989/28-Table1-1.png The attachments ^ means the number of b...
- Fri Dec 04, 2020 3:55 pm
- Forum: Lewis Structures
- Topic: Angles of Bonding Pairs
- Replies: 8
- Views: 460
Re: Angles of Bonding Pairs
how do you check to see if your bond angles are correct? or how to find them in general?
- Fri Dec 04, 2020 3:53 pm
- Forum: Dipole Moments
- Topic: Polarity from Shape
- Replies: 12
- Views: 681
Re: Polarity from Shape
are ALL bent molecules polar?
- Fri Dec 04, 2020 3:51 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 9
- Views: 585
Re: Resonance
Can someone explain the concept of resonance as well as how to find resonance structures? resonance and resonance structures are alternative modelings of compounds which may have different charges. Structures can also be labelled as having lower energy (more favorable) and higher energy (less favor...
- Fri Dec 04, 2020 3:43 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability and Polarizing Power
- Replies: 7
- Views: 530
Re: Polarizability and Polarizing Power
Hi! Does anyone have a good way to remember what makes an atom/ion more polarizable and which atoms/ions have more polarizing power? I'm having a little trouble with those concepts. For atoms that are more polarizable, the bigger the atom is = the more polarizable. I like to remember this by thinki...
- Sun Nov 29, 2020 11:56 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Character
- Replies: 33
- Views: 1469
Re: Covalent Character
Kat Stahl 1L wrote:I thought it was just the smaller the difference in electronegativity the more covalent character that bond has.
I also thought this to be true but I suppose there are multiple ways of determining covalent character ?
- Sun Nov 29, 2020 11:55 pm
- Forum: Sigma & Pi Bonds
- Topic: Delocalized and Localized Bonds
- Replies: 7
- Views: 1267
Re: Delocalized and Localized Bonds
What exactly is the significance of a delocalized bond? are there differences in strength between delocalized and localized ?
- Sun Nov 29, 2020 11:53 pm
- Forum: Lewis Structures
- Topic: Hybridization
- Replies: 4
- Views: 253
Re: Hybridization
will we be expected to determine hybridization from lewis structures and compounds, (ClSO4) for example, on an exam?
- Wed Nov 25, 2020 12:34 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Spin state
- Replies: 25
- Views: 1241
Re: Spin state
will spin state ever be on a final exam? I mean will we have to give the spin state by hand to the sub shell level?
- Wed Nov 25, 2020 12:31 am
- Forum: Bond Lengths & Energies
- Topic: Boiling/Melting Point
- Replies: 29
- Views: 1165
Re: Boiling/Melting Point
So do we always take the placement on the periodic table first, or simply look to electronegativity, if given?
- Mon Nov 16, 2020 8:52 pm
- Forum: Lewis Structures
- Topic: Drawing Lewis Structures When Given Name of Compound
- Replies: 1
- Views: 184
Drawing Lewis Structures When Given Name of Compound
Will we be expected to know or compose a lewis structures when given the name of the compound, such as "periodate ion" etc., on Midterm 2?
- Mon Nov 16, 2020 8:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v. Covalent Bonding
- Replies: 16
- Views: 771
Re: Ionic v. Covalent Bonding
Along with what everyone else has already said, a rough guideline for finding out if a bond is ionic or covalent is to find the difference in electronegativity between the two molecules. If the difference is greater than 2 then the bond is ionic, whereas if the difference is less than 1.5, the bond...
- Mon Nov 16, 2020 8:34 pm
- Forum: Lewis Structures
- Topic: Lewis acids and Bases
- Replies: 20
- Views: 751
Re: Lewis acids and Bases
How do you classify if a compound is a Lewis acid or base when given the chemical formula? Hi Michael! I had the same issue that you had in classifying the compounds, especially in Sapling. However, a quick note that might make it easier for you is that lewis acids are atoms that accept or take ele...
- Sun Nov 15, 2020 5:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v. Covalent Bonding
- Replies: 16
- Views: 771
Re: Ionic v. Covalent Bonding
how do we arrange bonds according to length? I believe this was in the sampling hw Q11. Bond length depends on the type of bond (single, double, triple) and the sizes of the atoms involved in the bond. Triple bonds are shorter than double bonds which are shorter than single bonds, given the bonds b...
- Sun Nov 15, 2020 5:04 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v. Covalent Bonding
- Replies: 16
- Views: 771
Re: Ionic v. Covalent Bonding
how do we arrange bonds according to length?
I believe this was in the sampling hw Q11.
I believe this was in the sampling hw Q11.
- Sun Nov 15, 2020 5:03 pm
- Forum: Resonance Structures
- Topic: Sapling Week 6 Number 9
- Replies: 5
- Views: 261
Re: Sapling Week 6 Number 9
later in this problem it asks us for the oxidation number of chlorine, how do we find this? Hi, the sum of the oxidation numbers of the atoms in ion must equal the charge on the ion, -1. When oxygen is bonded to a nonmetal other than F, it has an oxidation number of -2. This is since there are four...
- Sun Nov 15, 2020 5:01 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework due date
- Replies: 49
- Views: 2075
Re: Homework due date
which sections of hw will be on the midterm? I do not recall if it is cumulative or not... I'm pretty sure I remember my TA say in discussion that the midterms are not cumulative, so the next midterm should be based on the end of the week 2/3/4 homework on the quantum realm and the week 5/6 homewor...
- Sun Nov 15, 2020 4:46 pm
- Forum: Resonance Structures
- Topic: bond length
- Replies: 37
- Views: 1449
Re: bond length
so how are we able to see which bonds are longer or smaller? like in Q11 of the sapling week 5 and 6 HW?
- Sun Nov 15, 2020 4:44 pm
- Forum: Resonance Structures
- Topic: Sapling Week 6 Number 9
- Replies: 5
- Views: 261
Re: Sapling Week 6 Number 9
later in this problem it asks us for the oxidation number of chlorine, how do we find this?
- Sun Nov 15, 2020 4:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic v. Covalent Bonding
- Replies: 16
- Views: 771
Re: Ionic v. Covalent Bonding
Along with what everyone else has already said, a rough guideline for finding out if a bond is ionic or covalent is to find the difference in electronegativity between the two molecules. If the difference is greater than 2 then the bond is ionic, whereas if the difference is less than 1.5, the bond...
- Sun Nov 15, 2020 4:21 pm
- Forum: Lewis Structures
- Topic: Lewis acids and Bases
- Replies: 20
- Views: 751
Lewis acids and Bases
How do you classify if a compound is a Lewis acid or base when given the chemical formula?
- Sun Nov 15, 2020 4:19 pm
- Forum: Lewis Structures
- Topic: Nitrite vs Nitrate
- Replies: 17
- Views: 1210
Re: Nitrite vs Nitrate
Will we be expected to differentiate between compounds like this on the midterm?
- Fri Nov 06, 2020 5:03 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm grades
- Replies: 19
- Views: 811
Re: Midterm grades
Anh Trinh 1B wrote:MichaelMendozaD1F wrote:when will the answers be reviewed or released?
Dr. Lavelle will not release the answers, but in his email he said that he'll be going over the problems that students had the most difficulty during his upcoming final exam review sessions in Week 10!
thank you!
- Fri Nov 06, 2020 4:34 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 516875
Re: Saying Thank You to Dr. Lavelle
thank you for being so positive even when we are low on energy for faith in ourselves
- Fri Nov 06, 2020 4:32 pm
- Forum: General Science Questions
- Topic: Midterm 2
- Replies: 4
- Views: 195
Re: Midterm 2
so this midterm will be more conceptual ?
- Fri Nov 06, 2020 4:31 pm
- Forum: Student Social/Study Group
- Topic: Final Jitters
- Replies: 457
- Views: 336738
Re: Final Jitters
essential oil on the neck and temples helps
- Fri Nov 06, 2020 4:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework due date
- Replies: 49
- Views: 2075
Re: Homework due date
which sections of hw will be on the midterm? I do not recall if it is cumulative or not...
- Fri Nov 06, 2020 4:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm grades
- Replies: 19
- Views: 811
Re: Midterm grades
when will the answers be reviewed or released?
- Sun Nov 01, 2020 11:33 pm
- Forum: Student Social/Study Group
- Topic: Test Scored for Midterm 1
- Replies: 49
- Views: 2002
Re: Test Scored for Midterm 1
I am under the impression they will be released next week?
- Sun Nov 01, 2020 11:31 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Scores
- Replies: 28
- Views: 1137
Midterm Scores
When will our scores be released?
- Sun Nov 01, 2020 11:29 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Participation Points [ENDORSED]
- Replies: 62
- Views: 3359
Re: Participation Points [ENDORSED]
How are the points recorded?
- Sat Oct 24, 2020 5:11 pm
- Forum: Limiting Reactant Calculations
- Topic: Calculating Maximum Mass
- Replies: 3
- Views: 834
Re: Calculating Maximum Mass
hi, I finished this problem, but I had a question regarding the Na in the sodium hydroxide, where did it go? did we not include it in the ionic equation because it does not contain elements that formed the precipitate ? the products do not contain any Na molecules so I was curious as to where they w...
- Fri Oct 23, 2020 12:46 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Midterm 1
- Replies: 18
- Views: 579
Re: Midterm 1
Hey, I believe Heisenberg will be there since it was covered on the modules. Things to know related to this: 1) There is an indeterminacy in smaller objects as their momentum and velocity is unknown when interacting with light. For an object like a baseball, we can determine their position and mome...
- Fri Oct 23, 2020 12:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Nomenclature
- Replies: 3
- Views: 157
Re: Midterm Nomenclature
thank you! I was wondering the same thing since certain compounds are very tricky based on their placement and state of matter.
- Fri Oct 23, 2020 12:38 pm
- Forum: Student Social/Study Group
- Topic: Midterm Practice
- Replies: 5
- Views: 179
Re: Midterm Practice
based off feedback from my TA and Lavelle, the best review will come from the fundamental problems in the syllabus. However, his modules should also help as they are audio visual with a assessment portion that will count as even further review. Good luck!
- Fri Oct 23, 2020 12:34 pm
- Forum: Balancing Chemical Reactions
- Topic: L.3 Fundamental Question
- Replies: 3
- Views: 279
L.3 Fundamental Question
Compounds that can be used to store hydrogen in vehicles are being actively sought. One reaction being studied for hydrogen storage is Li3N(s) 1 2 H2(g) S LiNH2(s) 1 2 LiH(s). (a) What amount (in moles) of H2 is needed to react with 1.5 mg of Li3N? (b) Calculate the mass of Li3N that will produce 0....
- Fri Oct 23, 2020 12:32 pm
- Forum: Balancing Chemical Reactions
- Topic: L.1 Fundamental Question
- Replies: 2
- Views: 286
L.1 Fundamental Question
Without using a calculator, estimate what amount of Br2 (in moles) can be obtained from 0.30 mol ClO2 in the reaction 6 ClO2(g) 1 2 BrF3(l) S 6 ClO2F(s) 1 Br2(l).
- Mon Oct 19, 2020 10:31 am
- Forum: DeBroglie Equation
- Topic: De Broglie Equation cut off
- Replies: 6
- Views: 285
De Broglie Equation cut off
What is considered too small to calculate? 10^-38 and 10^-34 are too small to be measured yet 10^-10 is measurable. What is the cut off for detection?
- Mon Oct 19, 2020 10:07 am
- Forum: Administrative Questions and Class Announcements
- Topic: How to find my posts
- Replies: 163
- Views: 162110
Re: How to find my posts
I had trouble with this as well, as I submit all of my posts in one day, but today my posts had way less recorded. I hope this error will be fixed.
- Mon Oct 19, 2020 10:05 am
- Forum: *Black Body Radiation
- Topic: What is Black Body?
- Replies: 53
- Views: 2268
Re: What is Black Body?
I believe this concept will not be fully addressed until a more advanced chem lesson, however, I do recall him mentioning it being all consuming. I expect it to be in Chem 14B or further.
- Mon Oct 19, 2020 10:04 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Photoelectric Effect
- Replies: 6
- Views: 336
Re: Photoelectric Effect
I am also struggling with this topic in photoelectric effect, is there more review in the book? or is the sapling homework a better resource?
- Mon Oct 19, 2020 10:02 am
- Forum: Administrative Questions and Class Announcements
- Topic: Built-in webcams/Equipment request [ENDORSED]
- Replies: 22
- Views: 1511
Re: Built-in webcams/Equipment request [ENDORSED]
has there been an update about this requirement?
- Thu Oct 15, 2020 3:05 pm
- Forum: SI Units, Unit Conversions
- Topic: Webcam
- Replies: 11
- Views: 373
Webcam
Is the requirement of a webcam determined by our TA? or is it mandated by DR. Lavelle?
- Mon Oct 12, 2020 10:21 am
- Forum: Properties of Light
- Topic: Quanta and Photons
- Replies: 19
- Views: 327
Quanta and Photons
what exactly does "transferable" unit mean in the statement "However very sensitive experiment would show smallest 'transferable' unit is one (discrete) H20 molecule".
- Thu Oct 08, 2020 9:06 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamental Question E.17
- Replies: 3
- Views: 175
Fundamental Question E.17
E.17 Which sample in each of the following pairs contains the greater number of moles of atoms? (a) 75 g of indium or 80 g of tellurium; (b) 15.0 g of P or 15.0 g of S; (c) 7.36 3 1027 atoms of Ru or 7.36 3 1027 atoms of Fe.
(C in particular is becoming an issue for me)
(C in particular is becoming an issue for me)
- Thu Oct 08, 2020 9:03 pm
- Forum: Balancing Chemical Reactions
- Topic: Periodic Table
- Replies: 66
- Views: 4716
Re: Periodic Table
I believe we will be provided a periodic table, or allowed one, for every midterm or exam in Chem 40A :) hope you are well!
- Thu Oct 08, 2020 9:01 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamental Question E.23
- Replies: 3
- Views: 221
Fundamental Question E.23
E.23 Calculate the amount (in moles) of (a) Cu21 ions in 3.00 g of
CuBr;(b)SO moleculesin7.003102 mgofSO;(c)F2 ionsin 233
25.2 kg of UF6; (d) H2O in 2.00 g of Na2CO3?10H2O.
(I am confused as to why there are ions and what to convert them to if need be)
CuBr;(b)SO moleculesin7.003102 mgofSO;(c)F2 ionsin 233
25.2 kg of UF6; (d) H2O in 2.00 g of Na2CO3?10H2O.
(I am confused as to why there are ions and what to convert them to if need be)
- Thu Oct 08, 2020 8:58 pm
- Forum: Balancing Chemical Reactions
- Topic: butane balancing equation question
- Replies: 6
- Views: 293
Re: butane balancing equation question
I was able to calculate the net moles of gas by adding the stoichiometric coefficients of the "reactants" side of the equation, which will be 30, and then did the same to the "products" side of the equation to get 36. I then got a difference of 6 by subtracting moles of reactant ...
- Thu Oct 08, 2020 8:51 pm
- Forum: Empirical & Molecular Formulas
- Topic: Fundamental Question E.9
- Replies: 4
- Views: 154
Fundamental Question E.9
E.9 Epsom salts consist of magnesium sulfate heptahydrate. Write its formula. (a) How many atoms of oxygen are in 5.15 g of Epsom salts? (b) How many formula units of the compound are present in 5.15 g? (c) How many moles of water molecules are in 5.15 g of Epsom salts? (most difficulty is stemming ...