Search found 89 matches

by SamanthaTolentino 3D
Wed Jan 13, 2021 8:36 pm
Forum: General Science Questions
Topic: Acid & Base Equilibria Lecture Question
Replies: 7
Views: 50

Re: Acid & Base Equilibria Lecture Question

Just like in the previous unit on equilibria, we can leave out solvents such as water (liquids) and solids from the equilibrium equation. Water here is in excess and won't do much to the resulting reaction therefore we just leave it out. I think Lavelle gave the analogy of someone having 10 million ...
by SamanthaTolentino 3D
Wed Jan 13, 2021 8:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Why is the concentration of Ba2+ the same as barium hydroxide?
Replies: 7
Views: 30

Re: Why is the concentration of Ba2+ the same as barium hydroxide?

We use stoichiometric coefficients to determine the ratios. Since it is a 1:1 ratio, the concentrations will be the same for the products.
by SamanthaTolentino 3D
Wed Jan 13, 2021 8:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Class on 1/18/21 Holiday
Replies: 9
Views: 53

Re: Class on 1/18/21 Holiday

Dr. Lavelle just sent an email that there will be no class, peer learning session, nor office hours on Monday since its a holiday.
by SamanthaTolentino 3D
Wed Jan 13, 2021 8:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKw formula
Replies: 4
Views: 18

Re: pKw formula

It can be used for all acid and base reaction. The strength of the acid or base will be seen based on the pH or the pOH that you solved for.
by SamanthaTolentino 3D
Wed Jan 13, 2021 8:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Participation
Replies: 18
Views: 83

Re: Participation

You get points for all replies and posts that you make on the forum.
by SamanthaTolentino 3D
Wed Jan 13, 2021 8:29 pm
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 88
Views: 203

Re: Study Habits

Like a lot of people have said, step up and UA session might be a good place to start. If you can't make them, I believe there is a shared drive on the groupme. Last quarter, I would also cram doing all the textbook problems a couple days before the exams but I think it might be better to start work...
by SamanthaTolentino 3D
Wed Jan 06, 2021 10:49 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE tables
Replies: 4
Views: 22

Re: ICE tables

ICE charts can be used whenever you do not have information to either get the molar concentration or partial pressure. It can also be used with you are given the equilibrium constant but you do not have the equilibrium molar concentrations (given the initial molar concentrations instead)
by SamanthaTolentino 3D
Mon Jan 04, 2021 10:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Community Quota
Replies: 13
Views: 69

Re: Chemistry Community Quota

Hi, for each class of the chem series (A and B) with Lavelle we need 50 posts each. However, since you were not enrolled in Chem 14A with Lavelle, the total amount of posts that you should have by the end of the quarter should be 50 (5 posts per week).
by SamanthaTolentino 3D
Mon Jan 04, 2021 10:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 5
Views: 45

Sapling #5

Im stuck on #5 on the sapling homework which is attached. I don't know where to start but I was thinking along the lines that we have to use the K values given and find a way to simplify it to get the concentrations of each of the products and reactants. Would I need to create an ICE box for this as...
by SamanthaTolentino 3D
Mon Jan 04, 2021 10:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Error
Replies: 9
Views: 111

Re: Sapling Error

I had the same exact problem. I was able to enroll in the class after I enabled pop up windows.
by SamanthaTolentino 3D
Mon Jan 04, 2021 10:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook wording
Replies: 1
Views: 20

Re: Textbook wording

Yeah, when they talk about the "composition" they are talking in regards to the concentrations of the reactants and products if you have Kc. However, if u have Kp, you are looking in terms of the partial pressures of the products and reactants. Starting out with different concentrations of...
by SamanthaTolentino 3D
Mon Jan 04, 2021 10:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Hwk
Replies: 1
Views: 23

Sapling Hwk

Given this problem, how would I go about trying to solve the problem? I set up an ICE box but I'm not sure how to get the other values since we don't have any initial values for either PCl3 nor Cl2.
by SamanthaTolentino 3D
Thu Dec 10, 2020 10:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles
Replies: 12
Views: 85

Bond angles

Do we have to know the bond angles for the different shapes for the final?
by SamanthaTolentino 3D
Thu Dec 10, 2020 12:43 pm
Forum: Bronsted Acids & Bases
Topic: How do we know if its an acid or base?
Replies: 3
Views: 41

How do we know if its an acid or base?

Given the formula of the compounds, how do we determine whether or not something is an acid or a base. I know that typically, bases have OH in the end and acids start with H but for NH3 neither case can be used. I figured it would be an acid since it can give off a proton but the solution manual con...
by SamanthaTolentino 3D
Mon Dec 07, 2020 6:23 pm
Forum: Naming
Topic: Writing formulas for coordination compounds
Replies: 2
Views: 38

Writing formulas for coordination compounds

When we have to write the formula for a coordination compound such as sodium bisoxalato(diaqua)ferrate(III), does it matter the order that we put the ligands or do we do neutral atom and then charged anion? For example would these be interchangeable: Na[Fe(C202)2(H2O)2] Na[Fe(H2O)2(C202)2] or would ...
by SamanthaTolentino 3D
Mon Dec 07, 2020 2:30 pm
Forum: Identifying Acidic & Basic Salts
Topic: Metal Cations
Replies: 2
Views: 29

Re: Metal Cations

In the lecture, he stated that Mg+2 slightly lowers the pH but the book generalizes that group 1 and 2 cations do not affect the pH so were going to go with what the book states.
by SamanthaTolentino 3D
Mon Dec 07, 2020 2:29 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH 10^-14
Replies: 3
Views: 23

Re: pH 10^-14

pH 7 is the point where [OH-] and [H3O+] are equal because pH 7 is considered neutral. We know that the pH scale ranges from 0-14 but we also know that the concentrations of [OH-] and [H3O+] range from 1.0 to 1.0 x10^-14.

14= (pH of OH-) + (pH of H30+)
by SamanthaTolentino 3D
Mon Dec 07, 2020 2:24 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 4
Views: 47

Re: Conjugate Acids and Bases

Conjugate base (comes from an acid) is the remaining compound/element/species after the acid donates a proton. Conjugate acid (comes from a base) is the remaining species formed when a base accepts a proton.
by SamanthaTolentino 3D
Mon Dec 07, 2020 2:21 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH vs pOH
Replies: 9
Views: 63

Re: pH vs pOH

Like pH, pOH also goes from 1-14. When given the pH, we can calculate the pOH value by the idea that 14= pH +pOH
by SamanthaTolentino 3D
Mon Dec 07, 2020 1:49 pm
Forum: Administrative Questions and Class Announcements
Topic: Unable to view the lectures
Replies: 12
Views: 111

Unable to view the lectures

Is anyone else struggling to make the bruin cast lectures play? I already downloaded the the UCLA vpn and even tried using the 2nd video but it still gives me an error. Does anyone know how to fix this problem?
by SamanthaTolentino 3D
Fri Dec 04, 2020 11:01 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 - Missed Questions
Replies: 2
Views: 39

Midterm 2 - Missed Questions

In order to find out which questions we got wrong for the midterm, do we have to go to our TA's office hours or can we go to any TA's.
by SamanthaTolentino 3D
Mon Nov 30, 2020 11:48 pm
Forum: Student Social/Study Group
Topic: Time differences with final exams
Replies: 6
Views: 79

Re: Time differences with final exams

Hi, I think there are 2 options for the final exam, one specifically for international students. It might be best to email ur TA to see if you could possibly take it during the 2nd time slot.
by SamanthaTolentino 3D
Mon Nov 30, 2020 11:46 pm
Forum: Naming
Topic: Using ido or o
Replies: 24
Views: 122

Re: Using ido or o

Dr. Lavelle went over it during his lecture and said that both ways are acceptable. The textbook and sapling use -ido meanwhile he uses -o.
by SamanthaTolentino 3D
Mon Nov 30, 2020 11:44 pm
Forum: Student Social/Study Group
Topic: Week 8/9 Thoughts/Worries
Replies: 66
Views: 465

Re: Week 8/9 Thoughts/Worries

I feel like its pretty decent overall. The grading scale for this class is kinda scary and there's no room for error so I'm kinda scared for the final. Overall though, there are a lot of review sessions and workshops available to us. Im also split about having the tests mc because its all or nothing...
by SamanthaTolentino 3D
Mon Nov 30, 2020 11:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Final exam (fall 2020 quarter)
Replies: 20
Views: 216

Re: Final exam (fall 2020 quarter)

The final exam is cumulative. Someone in the groupme mentioned that some questions from the previous midterms may pop us as well but im not too sure. I think Dr. Lavelle will specify in the upcoming weeks, especially when he releases the review schedule for the final.
by SamanthaTolentino 3D
Mon Nov 30, 2020 11:37 pm
Forum: General Science Questions
Topic: study methods/recs
Replies: 37
Views: 276

Re: study methods/recs

I usually go through the sections in the textbook that are covered in class and take notes on it. The information is repeated and at the same time you get another explanation of the main concepts. I usually make a quizlet from the notes I took from the lectures and the textbook and use that to revie...
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:28 pm
Forum: Lewis Structures
Topic: Question on Radical -- SAPLING BOOK (Mistake in Answer Key)
Replies: 6
Views: 63

Re: Question on Radical -- SAPLING BOOK (Mistake in Answer Key)

NO2- is not a radical because it has an even number of electrons. Nitrogen has a total of 7 electrons while oxygen has a total of 16. Since it has a negative charge, we add another electron which adds up to 24 electrons which means that it is not a radical.
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Expanded Octets
Replies: 9
Views: 85

Re: Expanded Octets

I think the general rule for expanded octets is that they must be in period 3 or higher because this is when the d orbitals are first occupied.
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear vs Cyclic
Replies: 2
Views: 29

Re: Linear vs Cyclic

There are different lewis structures that we can make out of a given formula. For the sapling homework, either 17 or 18 we have C3H4 and we can draw 3 different structures that aren't necessarily resonance structures. It states in the "hint" portion that one of it is cyclical so I think we...
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:14 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 8 Participation Points
Replies: 6
Views: 58

Re: Week 8 Participation Points

I think its still the same amount of posts since we need a total of 50 points at the end of the quarter.
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:13 pm
Forum: Electronegativity
Topic: How to memorize
Replies: 6
Views: 65

Re: How to memorize

I dont think we necessarily have to memorize the exact electronegative values for each of the element. Just know that fluorine is the most electronegative element since it is at top left of the periodic table. Electronegativity increases across a group and down a period.
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:11 pm
Forum: Administrative Questions and Class Announcements
Topic: grades
Replies: 10
Views: 151

Re: grades

alebenavides wrote:does anyone know if the midterms are curved ?

The midterms aren't curved and they're all out of the 110 points. Im not sure about the grade distribution and percentages for As and Bs but we need at least 50% of the points to get a C.
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Homework
Replies: 2
Views: 15

Sapling Homework

On the sapling homework it states that one of the lewis structures is in a cyclic shape but the molecule is C3H4. Would a triangle shape between the carbon atoms still count as cyclic or do we have to include the hydrogens within the cyclical model?
by SamanthaTolentino 3D
Tue Nov 24, 2020 10:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Grade distribution
Replies: 1
Views: 49

Grade distribution

Since we need at least 50% of the points to at least get a C in the class, are the distributions for A and Bs altered as well or are they regular (A = 100-90 and B=89-80). Thank you
by SamanthaTolentino 3D
Sat Nov 21, 2020 11:16 pm
Forum: Ionic & Covalent Bonds
Topic: Radicals
Replies: 10
Views: 86

Re: Radicals

Yeah, it would be a radical since it contains an uneven amount of electrons. You can check on Dr. Lavelle's website for the solution manual errors if you ever come across an answer on the solution manual that seems incorrect.
by SamanthaTolentino 3D
Sat Nov 21, 2020 11:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground State vs. Excited State
Replies: 6
Views: 74

Re: Ground State vs. Excited State

The ground state configuration of an atom is when all principles such as Pauli's exclusion principle and hunds rule are obeyed. An atom is in an excited state when it does not obey the rules. For example for Oxygen, it would be in an excited state of the electrons in the p orbital were all paired ra...
by SamanthaTolentino 3D
Sat Nov 21, 2020 11:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook practice problem 2E.1
Replies: 4
Views: 20

Re: Textbook practice problem 2E.1

It is still possible to have lone pairs and be linear. If the central atom has 3 lone pairs as well as 2 outer atoms, the 3 lone pairs will occupy the equatorial plane thus leaving the 2 outer atoms both on the axial planes. This would result in a 180 angle and thus a linear shape.
by SamanthaTolentino 3D
Sat Nov 21, 2020 11:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework Problem 2E.1
Replies: 3
Views: 49

Re: Homework Problem 2E.1

This chart might be helpful in remembering the shapes when there are lone pairs involved. It was a part of the feedback portion for the sapling questions of week7/8 problems.
by SamanthaTolentino 3D
Sat Nov 21, 2020 11:06 pm
Forum: Ionic & Covalent Bonds
Topic: Rules of ionization energy
Replies: 18
Views: 114

Re: Rules of ionization energy

Ionization increases across a period since the atomic radius is smaller and the electrons are more tightly held thus requiring more energy to remove the electron. It decreases down a group since the atomic radius is increasing and electrons aren't as tightly held and are shielded from the positive c...
by SamanthaTolentino 3D
Sat Nov 21, 2020 11:05 pm
Forum: Student Social/Study Group
Topic: Study Tips for Final Exam
Replies: 57
Views: 397

Re: Study Tips for Final Exam

Since Dr. Lavelle said that textbook questions often show up on the midterms and finals as we saw, I'm probably going to redo the textbook questions that are assigned as well as rereading my notes from all the lectures. Im also probably going to try to attend some of the review sessions (Justin's sp...
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:35 am
Forum: Resonance Structures
Topic: Resonance structures contribution to overall structure
Replies: 4
Views: 17

Re: Resonance structures contribution to overall structure

You determine which resonance structure contributes the least to the overall structure would be the one that has most formal charges, although they may cancel out or still add up to the overall net charge. We want to have stable forms of the atom which would mean a 0 formal charge for that element/a...
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:32 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Study Session?
Replies: 4
Views: 59

Re: Midterm 2 Study Session?

I haven't heard anything yet either. You might want to check with the UA that held the session last time to see if he is doing another one for this midterm. I think the UA was Justin.
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:31 am
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 22
Views: 125

Midterm 2

How are you guys studying for the 2nd midterm? Will you be focusing more on the sapling homework or the textbook?
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:29 am
Forum: Electronegativity
Topic: Sapling #14
Replies: 10
Views: 69

Re: Sapling #14

Hydrogen bonding is present in molecules with N, O, and F. It must be covalently bonded to an electronegative atom (N,O,F) and close to another electronegative atom that has an available lone pair.
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:27 am
Forum: Lewis Structures
Topic: Double Bonds
Replies: 11
Views: 85

Re: Double Bonds

The formal charge is typically what we look at to determine which gets the double bond. We want a more stable atom so we want most of the molecules to have a 0 formal charge which is most favorable/stable.
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:25 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Repulsion
Replies: 9
Views: 74

Re: Repulsion

The repulsion between 2 lone pairs in comparison to the repulsion of bonding pairs because 2 lone pairs typically are 2 negatively charged electrons and we know that opposite charges repel. Bonding pairs on the other hand are more attractive, positive and negative charges.
by SamanthaTolentino 3D
Fri Nov 13, 2020 11:23 am
Forum: Coordinate Covalent Bonds
Topic: Hydrogen bonding
Replies: 15
Views: 111

Re: Hydrogen bonding

I think a hydrogen bond is its own type of bonding and is not a coordinate covalent bond.
by SamanthaTolentino 3D
Wed Nov 04, 2020 2:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem community posts
Replies: 4
Views: 28

Chem community posts

If we post more than 5 times on chem community within a given week, will it be carried over to the next weed since we can only earn a maximum of 50 chem community points per quarter or will we simply just start from the next week and the extra posts are simply just extra?
by SamanthaTolentino 3D
Wed Nov 04, 2020 2:38 pm
Forum: Lewis Structures
Topic: Where does the formal charge go?
Replies: 4
Views: 31

Re: Where does the formal charge go?

The formal charge can be added to each element by clicking more and choosing either the red or green circles depending on whether or not it is a positive or negative charge. The brackets that professor uses in his lectures are used to display the overall charge of the molecule not the formal charge ...
by SamanthaTolentino 3D
Wed Nov 04, 2020 2:36 pm
Forum: Resonance Structures
Topic: Delocalized e-
Replies: 5
Views: 50

Re: Delocalized e-

To add on, electrons involved in resonance structures are seen to be delocalized. Electrons that are delocalized are more stable.
by SamanthaTolentino 3D
Wed Nov 04, 2020 2:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14B Enrollment
Replies: 27
Views: 303

Re: Chem 14B Enrollment

Personally, I am using my first pass to enroll in LS30B and Chem14A so that I have my main classes and the times set so that I could plan my other GE's around the class times instead of the other way around.
by SamanthaTolentino 3D
Wed Nov 04, 2020 2:31 pm
Forum: Octet Exceptions
Topic: Limit to octet exception
Replies: 2
Views: 34

Re: Limit to octet exception

I believe it is just the amount of electrons that can be held in the d-block which would be a max of 10 electrons. There are other blocks which possibly could contain more electrons but I don't think we will go over that.
by SamanthaTolentino 3D
Wed Nov 04, 2020 2:29 pm
Forum: Resonance Structures
Topic: Bond lengths
Replies: 2
Views: 41

Bond lengths

Given expected bond lengths, how are we able to determine which bond character occur within those structures? For example these values are given and we are asked to choose the correct statements: the carbon--oxygen bonds has overwhelmingly C--O bond character the carbon--nitrogen bonds has overwhelm...
by SamanthaTolentino 3D
Wed Oct 28, 2020 1:14 pm
Forum: Quantum Numbers and The H-Atom
Topic: How many electrons in an atom could have these sets of quantum numbers?
Replies: 3
Views: 29

How many electrons in an atom could have these sets of quantum numbers?

How many electrons in an atom could have these sets of quantum numbers?


n=7,l=1,ml=-1

I know that it is in 7p which would have at most 6 electrons. How would I factor the ml value to find how many electrons are in this set of quantum numbers.
by SamanthaTolentino 3D
Tue Oct 27, 2020 5:33 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum numbers
Replies: 3
Views: 49

Quantum numbers

If ml = l,(1-1), -l how would we figure out the true value of ml. In Friday's lecture, Professor Lavelle gave the example of n=2 therefore l=1 and ml =-1. However, he stated that ml could be 3 different values. How would we specify which value of ml we should take?
by SamanthaTolentino 3D
Mon Oct 26, 2020 9:16 pm
Forum: Student Social/Study Group
Topic: Studying Concepts
Replies: 6
Views: 65

Re: Studying Concepts

I would go through the post module assessments of the audiovisual topic since they cover all the topics that will be on the midterm. The organic chemistry tutor on youtube is helpful as well. I usually watch his videos if I don't understand a concept on the module or want to view more step by step p...
by SamanthaTolentino 3D
Mon Oct 26, 2020 9:14 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Uncertainty Module Example Question
Replies: 3
Views: 76

Re: Heisenberg Uncertainty Module Example Question

To solve this problem, you can use the Heisenbergs uncertainty principle but instead of delta P, you can simply just use delta V and mass. The equation would look like:

Delta V > h/4pi(mass)(uncertainty in position)
by SamanthaTolentino 3D
Mon Oct 26, 2020 9:09 pm
Forum: Properties of Electrons
Topic: Sapling Homework #14
Replies: 5
Views: 78

Re: Sapling Homework #14

Maybe double check your significant figures and whether or not you're using the right exponents for the scientific notation. Sapling is pretty picky sometimes and it will mark your answer wrong if the sig figs are slightly off.
by SamanthaTolentino 3D
Mon Oct 26, 2020 9:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Modules
Replies: 4
Views: 40

Re: Modules

Hi, I don't think there will be any modules for the upcoming modules. If so, he would have probably emailed us about the modules we should have completed before week 4.
by SamanthaTolentino 3D
Mon Oct 26, 2020 9:03 pm
Forum: Balancing Chemical Reactions
Topic: Text Book Problems
Replies: 2
Views: 45

Re: Text Book Problems

I don't think we have to know net ionic equations or name compounds that are not common like water or elements by themselves. If anything they will be given if it is needed for a problem. It is not one of the concepts that is included in outline 1 or 2.
by SamanthaTolentino 3D
Mon Oct 26, 2020 8:59 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Inconsistencies in Delta Values
Replies: 4
Views: 53

Re: Inconsistencies in Delta Values

If the uncertainty is given as a +/- we use the difference. For example, uncertainty 10 +/- 5 therefore the uncertainty we would use would be 10. However when the uncertainty is just given, diameter of an atom is " " then we would use that value. Hope this helps!
by SamanthaTolentino 3D
Mon Oct 26, 2020 2:47 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Module
Replies: 3
Views: 61

Heisenberg Module

Im reviewing the post module assessments in preparation for the upcoming midterm and came across this question: Two students are studying together when Bob says I do love you Alice and Alice responds "But how can I be sure?" Would using Heisenberg's uncertainty principle help them determin...
by SamanthaTolentino 3D
Thu Oct 22, 2020 9:09 pm
Forum: Einstein Equation
Topic: Sapling Homework - electron affinity
Replies: 5
Views: 82

Re: Sapling Homework - electron affinity

I get 9.676 x 10^1 kj/mol however sapling still marks it incorrect. Is there another way to solve this problem?
by SamanthaTolentino 3D
Thu Oct 22, 2020 8:12 pm
Forum: Einstein Equation
Topic: Sapling Homework - electron affinity
Replies: 5
Views: 82

Sapling Homework - electron affinity

The electron affinity of thulium has been measured by a technique known as laser photo-detachment electron spectroscopy. In this technique, a gaseous beam of the anions of an element is bombarded with photons from a laser. Electrons from the anion are then ejected and their energies are detected. Th...
by SamanthaTolentino 3D
Thu Oct 22, 2020 7:52 pm
Forum: DeBroglie Equation
Topic: Sapling Homework - electron affinity
Replies: 9
Views: 107

Sapling Homework - electron affinity

The E.Coli bacterium is about 2.2 μm long. Suppose you want to study it using photons of that wavelength or electrons having that de Broglie wavelength. What is the energy of the photon? What is the energy of the electron? Im struggling on where to start. Do I assume that the length of the bacteria ...
by SamanthaTolentino 3D
Wed Oct 21, 2020 10:47 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm Exam Format
Replies: 1
Views: 35

Midterm Exam Format

Will we need to know how to create the equation for a chemical for the midterm? For example, would we need to know the element notation for magnesium chloride or will the midterm just cover the fundamental sections shown in outline 1. Thank you!
by SamanthaTolentino 3D
Tue Oct 20, 2020 7:07 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals F
Replies: 2
Views: 54

Fundamentals F

A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfer into a flask to obtain (a) 2.15 mmol Na1; (b) 4.98 mmol ...
by SamanthaTolentino 3D
Mon Oct 19, 2020 1:08 pm
Forum: Photoelectric Effect
Topic: Light Intensity
Replies: 23
Views: 107

Re: Light Intensity

Increasing the intensity of the light meant increasing the amount of photons being aimed at the metal. Professor Lavelle gave an example with cross country runners and how increasing the intensity of runners meant increasing the number of runners.
by SamanthaTolentino 3D
Mon Oct 19, 2020 1:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy vs Emission Spectrum
Replies: 3
Views: 14

Re: Atomic Spectroscopy vs Emission Spectrum

Atomic spectroscopy is the study of the em radiation that is absorbed or emitted by an electron. The emission spectrum is a specific type of atomic spectroscopy where they evaluate the light that is emitted, thus being called the emission spectrum. There is also the absorption spectrum where they ev...
by SamanthaTolentino 3D
Mon Oct 19, 2020 1:01 pm
Forum: Properties of Light
Topic: Midterm
Replies: 42
Views: 390

Re: Midterm

His announcement on his class website told us what concepts from outline 1 and 2 will be on the midterm. On the syllabus it also says that its a 50 minute midterm in our discussion so I would assume it might be similar to the amount of problems on the post module assessments since he says those shou...
by SamanthaTolentino 3D
Mon Oct 19, 2020 12:58 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1259

Re: How are you studying?

I take notes on the lecture and then refer back to the book to compare the notes I took on the lecture and the information in the book. For the midterm, I'm planning on redoing the homework problems listed on the outline as well as some of the post module assessments. Im also going to look over the ...
by SamanthaTolentino 3D
Mon Oct 19, 2020 12:56 pm
Forum: DeBroglie Equation
Topic: Wave Properties of Electrons
Replies: 4
Views: 36

Re: Wave Properties of Electrons

This visual might help!
by SamanthaTolentino 3D
Mon Oct 19, 2020 12:53 pm
Forum: DeBroglie Equation
Topic: Wave Properties of Electrons
Replies: 4
Views: 36

Re: Wave Properties of Electrons

It means that when an electron passes through a crystal ( or a wall with a gap might be easier to think of) , we don't find the electron in just one spot. The electron acts as a wave therefore, when it passes through the crystal (or the spot on the wall) , there are waves which interact resulting in...
by SamanthaTolentino 3D
Mon Oct 19, 2020 12:49 pm
Forum: DeBroglie Equation
Topic: E=pc Equation
Replies: 3
Views: 39

Re: E=pc Equation

I think when he wrote that equation, he was talking about how light does not have a rest mass but it has momentum therefore, the energy of light = momentum* speed of light.
by SamanthaTolentino 3D
Mon Oct 19, 2020 12:08 pm
Forum: DeBroglie Equation
Topic: Wavelike properties of an Object
Replies: 5
Views: 42

Wavelike properties of an Object

What is a good number that we could consider for the wavelength to determine that it has wavelike properties? For example, like anything below 10^-5 would not have any wavelike properties. What is a number or approximate number we could set as a line between observable wavelike properties and non-ob...
by SamanthaTolentino 3D
Thu Oct 15, 2020 8:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Exam Format
Replies: 14
Views: 96

Midterm Exam Format

Will the midterms and finals be multiple choice?
by SamanthaTolentino 3D
Tue Oct 13, 2020 4:29 pm
Forum: Properties of Electrons
Topic: Wavelike characteristics of objects
Replies: 4
Views: 46

Re: Wavelike characteristics of objects

HI, yes you are unable to see the wavelengths of large objects because they are very small. The visible eye can only see through the visible region of the em spectrum and these wavelengths are in nanometers. Large objects when we calculate go beyond 10^-9
by SamanthaTolentino 3D
Tue Oct 13, 2020 4:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Proctoring of Exams?
Replies: 2
Views: 62

Re: Proctoring of Exams?

My TA said that we need to download respondus. You can find the link on the CCLE class website. We also are required to have an external webcam in order to monitor our workspace. As far as the TA proctoring our exam, all I know is that we will be taking our midterms and finals during our discussion ...
by SamanthaTolentino 3D
Tue Oct 13, 2020 4:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Webcam
Replies: 5
Views: 117

Re: Webcam

My TA said that Professor Lavelle wanted an external webcam so that one could be used to view the exam and the other to view your workspace. However, she did say that she would ask if we are able to use our phones as the second camera instead.
by SamanthaTolentino 3D
Tue Oct 13, 2020 4:19 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 4
Views: 28

Re: Work Function

I think you would only be required to divide by avogadro's constant if the question were to ask for the work function per mole of a photon.
by SamanthaTolentino 3D
Tue Oct 13, 2020 4:02 pm
Forum: Properties of Light
Topic: Sapling Week 2/3 Homework
Replies: 3
Views: 24

Sapling Week 2/3 Homework

Consider a single photon with a wavelength, frequency and an energy. What is the wavelength frequency, and energy of a pulse of light containing 100 of these photons?

Where would I start in solving this problem?
by SamanthaTolentino 3D
Tue Oct 13, 2020 11:34 am
Forum: Properties of Light
Topic: Discussion Session Problem: How many photons are emitted?
Replies: 2
Views: 33

Discussion Session Problem: How many photons are emitted?

A lamp rated at 32W (1W=1 J.S^-1) emits violet light of wavelength 420 nm. How many photons of violet light can the lamp generate in 2.0s? How many moles of photons are emitted in that time interval? I already calculated the energy per photon which is 4.7 x 10^-18 J/photon. After this, would I need ...
by SamanthaTolentino 3D
Wed Oct 07, 2020 8:17 pm
Forum: Photoelectric Effect
Topic: Focus 1 Textbook problem 15
Replies: 1
Views: 32

Focus 1 Textbook problem 15

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. How would I determine the final energy level of the electron? I know that ...
by SamanthaTolentino 3D
Wed Oct 07, 2020 5:55 pm
Forum: Molarity, Solutions, Dilutions
Topic: Audio Visual Modules
Replies: 4
Views: 51

Audio Visual Modules

When should we complete the last 4 modules on the chem website (photoelectric effect through the heinsenberg uncertainty principle)? Also are the modules above the last 4 topics (wave properties of light, chemical vs quantum mechanics) fundamental review before we work on the last 4 modules?
by SamanthaTolentino 3D
Mon Oct 05, 2020 9:21 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mol VS Mole
Replies: 17
Views: 213

Re: Mol VS Mole

Yeah, they're the same exact thing. Mol for Mole is basically the same exact thing as L for Liters
by SamanthaTolentino 3D
Mon Oct 05, 2020 9:20 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 11
Views: 118

Re: Sig Figs

There are 4 significant figures since leading zeros do not count. The zeros in middle of 3024 in 0.003024 count because it is in between significant digits.
by SamanthaTolentino 3D
Mon Oct 05, 2020 9:18 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 97
Views: 7090

Re: Accessing the E-textbook [ENDORSED]

Does anyone know what the Sapling learning thing is? I heard it was extra practice but I was wondering how to access it/what kind of practice it was. Sapling learning is what we will be using to turn in our homework, the part that is graded. The extra practice will be the textbook questions that ar...
by SamanthaTolentino 3D
Mon Oct 05, 2020 12:02 pm
Forum: Molarity, Solutions, Dilutions
Topic: Units for Dilution Equation [ENDORSED]
Replies: 23
Views: 208

Re: Units for Dilution Equation [ENDORSED]

Since the units for molarity is mol.L-1 which is in liters, you have to maintain that same unit when using M1V1=M2V2. If the question wants the answer in mL, you can always convert the answer you get to the needed unit.
by SamanthaTolentino 3D
Mon Oct 05, 2020 11:58 am
Forum: Balancing Chemical Reactions
Topic: Balancing chemical equations involving combustion
Replies: 15
Views: 117

Re: Balancing chemical equations involving combustion

When anything is "combusted" or oxidized, we know that oxygen is always one of the reactants and we know that the products of combustion will always be CO2 as well as H20.

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