Search found 100 matches

by Lucy Weaver 1K
Mon Feb 22, 2021 1:16 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Conceptual understandings
Replies: 7
Views: 31

Re: Conceptual understandings

Electrochemistry has definitely felt more confusing than thermodynamics for me too. I think the Organic Chemistry Tutor on YouTube has really helped me though! This video goes through balancing redox half reactions in acidic or basic solutions, and it really helped me with some of the textbook prob...
by Lucy Weaver 1K
Mon Feb 22, 2021 11:58 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Conceptual understandings
Replies: 7
Views: 31

Conceptual understandings

For some reason this topic is just not landing with me when I watch the lectures, I don't know if its because I'm trying to write down all the concepts as Lavelle talks about them so I'm not actually internalizing the information or if it's just a hard topic, but I feel like I leave lecture not real...
by Lucy Weaver 1K
Sun Feb 21, 2021 9:50 pm
Forum: Balancing Redox Reactions
Topic: Sapling question 3
Replies: 2
Views: 22

Sapling question 3

For some reason, I've been struggling with this problem. I cannot get the balanced equation, I've been balancing the half equations and adding water. So far my half equations look like this SO32- + H2O--> SO42- + H2 + 2e- 2Ag+ + 2e- --> 2Ag I'm not sure where I'm going wrong here, if someone could s...
by Lucy Weaver 1K
Sun Feb 21, 2021 9:30 pm
Forum: Balancing Redox Reactions
Topic: Sapling question 2
Replies: 3
Views: 12

Re: Sapling question 2

RylanPurificacion 3J wrote:Are you capitalizing the letters? Sapling can get pretty specific with that, and I noticed that I had to capitalize each element or else nothing would show up.

Thank you! I wasn't capitalizing them
by Lucy Weaver 1K
Sun Feb 21, 2021 9:01 pm
Forum: Balancing Redox Reactions
Topic: Sapling question 2
Replies: 3
Views: 12

Sapling question 2

I'm having a hard time formatting this answer.. I try to type in the reaction but it won't let me type actual letters. I'm probably just being stupid but what should the format of the actual answer to this look like?
by Lucy Weaver 1K
Sun Feb 21, 2021 8:46 pm
Forum: Administrative Questions and Class Announcements
Topic: struggling
Replies: 66
Views: 214

Re: struggling

I also recommend reading the textbook, it helps me because it concentrated on minute details and gives lots of examples on how to work through problems, and I find that it often includes things that Lavelle sometimes leaves out of his lectures.
by Lucy Weaver 1K
Sun Feb 21, 2021 8:42 pm
Forum: Balancing Redox Reactions
Topic: cool acronym
Replies: 25
Views: 96

Re: cool acronym

Very helpful thank you for this!
by Lucy Weaver 1K
Sun Feb 21, 2021 8:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Porous vs Salt
Replies: 2
Views: 13

Re: Porous vs Salt

I think for the purposes of this class they are essentially the same thing and they serve the same purpose
by Lucy Weaver 1K
Sun Feb 21, 2021 8:37 pm
Forum: Balancing Redox Reactions
Topic: Oxidation numbers
Replies: 4
Views: 24

Oxidation numbers

Is there any easy way to remember how to find oxidation numbers of compounds or should we memorize them?
by Lucy Weaver 1K
Thu Feb 18, 2021 4:55 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Monatomic and Linear Gases
Replies: 4
Views: 16

Monatomic and Linear Gases

Should we be able to identify whether a gas is monatomic or linear for Midterm 2? / can anyone give me some examples of these?
by Lucy Weaver 1K
Sun Feb 14, 2021 7:50 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Sapling question 7
Replies: 8
Views: 38

Sapling question 7

Does anyone understand why the higher entropy values were the ones associated with being the most ordered in this problem? I was under the impression that a higher entropy value would mean more disorder. C2H5OH has a delta S of 121.75, C6H6 has a delta s of 33.77 and C4H10 has a delta s of 21.6.
by Lucy Weaver 1K
Sun Feb 14, 2021 6:35 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling question 18
Replies: 4
Views: 30

Sapling question 18

For this problem, the way I am going about it is by first subtracting deltaG (products) - deltag(reactants). I then use the equation deltag = -RTln(k) to solve for k, making sure to convert joules of the ideal gas constant to kj, and I keep getting it wrong. Does anyone know what I'm doing wrong or ...
by Lucy Weaver 1K
Sun Feb 14, 2021 6:29 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling 18
Replies: 3
Views: 24

Re: Sapling 18

Hey! So for problem 18 its asking you to find K values for certain reactions given the reactants and products ΔG of formation values. In order to find this you multiply the ΔG of formation of each product and reactant by their stoichiometric coefficients, then add the ΔG of the products and subtrac...
by Lucy Weaver 1K
Sun Feb 14, 2021 6:25 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling Week 5/6 #5
Replies: 7
Views: 64

Re: Sapling Week 5/6 #5

You are not solving for mols correctly, I also did this incorrectly to start and found .4068 to be the molar heat capacity. To solve for molar heat capacity using PV=nRT, you need to use 298.25 K as the temperature since we're solving for initial mols. using this to solve for n (.0986*18=n*.0826*29...
by Lucy Weaver 1K
Sat Feb 13, 2021 6:19 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling question 5
Replies: 2
Views: 14

Sapling question 5

How are people finding the equation delta s= cv*ln(t2/t1) because I don't have it in my notes from the lecture, was it in the textbook?
by Lucy Weaver 1K
Sat Feb 13, 2021 6:12 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling Week 5/6 #5
Replies: 7
Views: 64

Re: Sapling Week 5/6 #5

You are not solving for mols correctly, I also did this incorrectly to start and found .4068 to be the molar heat capacity. To solve for molar heat capacity using PV=nRT, you need to use 298.25 K as the temperature since we're solving for initial mols. using this to solve for n (.0986*18=n*.0826*298...
by Lucy Weaver 1K
Sat Feb 13, 2021 5:44 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling question 4
Replies: 9
Views: 27

Sapling question 4

Does anyone understand how to do this question because I'm very lost as to where we start. Any help would be appreciated, thanks!
by Lucy Weaver 1K
Sun Feb 07, 2021 7:02 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Sapling #18
Replies: 4
Views: 35

Re: Sapling #18

This is my work from this problem with my given values if it helps, sometimes it helps me to actually see it written out
by Lucy Weaver 1K
Sun Feb 07, 2021 6:44 pm
Forum: Calculating Work of Expansion
Topic: Sapling #14 for Wk 3 and 4
Replies: 12
Views: 65

Re: Sapling #14 for Wk 3 and 4

I think we use two different values for R because the first value of .0826 has units of L atm K−1 mol−1, which are the units we need because we are dealing with temperature, atm, and mols and we want to be left with units respective to L since in the next part we are dealing with calculations relati...
by Lucy Weaver 1K
Sun Feb 07, 2021 6:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 19 sapling
Replies: 3
Views: 37

Question 19 sapling

Why do we ignore the masses given in this problem? I noticed the only thing you need to do to solve this is divide the q given by the origional change in temperature to obtain the heat capacity of the calorimeter and then multiply this value by the second change in t to obtain the new delta U, but i...
by Lucy Weaver 1K
Sun Feb 07, 2021 4:10 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Cp and Cv
Replies: 7
Views: 46

Cp and Cv

How does Cv relate to the constant‑pressure molar specific heat, Cp?
by Lucy Weaver 1K
Sun Feb 07, 2021 3:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: sapling question 14 week 5
Replies: 3
Views: 56

sapling question 14 week 5

Can anyone explain how they found the answer to part a of this question? Somehow I've found path b but keep getting a wrong
by Lucy Weaver 1K
Sun Jan 31, 2021 4:52 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calculating heat of combustion
Replies: 1
Views: 23

Calculating heat of combustion

for the question: Suppose a 3.813 g sample of a second compound, compound B, is combusted in the same calorimeter, and the temperature rises from 24.45 ∘C to 28.32 ∘C. What is the heat of combustion per gram of compound B? Why do we multiply c* delta t and then divide by mass of compound b if the eq...
by Lucy Weaver 1K
Sun Jan 31, 2021 4:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: When to convert mass of a substance given to moles
Replies: 5
Views: 44

When to convert mass of a substance given to moles

I notice in question 10 on sapling week 3 and 4 homework, we convert the mass of ice given to moles in order to multiply by specific heat capacity, but in question 11 we don't convert the mass of aluminum given to moles. How do we know when to do this conversion and when not to?
by Lucy Weaver 1K
Sun Jan 31, 2021 2:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: How to calculate change in temperature
Replies: 3
Views: 34

How to calculate change in temperature

This might be a silly question, but for number 9 on the sapling homework for weeks 3 and 4, i'm confused on if we've learned how to do this yet: If you combine 320.0 mL of water at 25.00 ∘C and 120.0 mL of water at 95.00 ∘C, what is the final temperature of the mixture? Use 1.00 g/mL as the density ...
by Lucy Weaver 1K
Wed Jan 27, 2021 3:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook problem 5I.13
Replies: 1
Views: 12

Textbook problem 5I.13

For some reason I keep getting this problem wrong, I am finding the equillibrium concentration of Cl for thefirs part by using the equation they give us in the table. I first convert 2 mmol to .002 mol, set up my ice table and use the k value to solve for the [cl] concentration at equillibrium but I...
by Lucy Weaver 1K
Mon Jan 25, 2021 3:08 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Monday's lecture clarification
Replies: 3
Views: 33

Monday's lecture clarification

In the last half of the lecture today when he was calculating the last example, did anyone understand the process he went through to obtain the value -2.9 kj? At one point I think he said it was actually 2900, and if so why did he find it to be 2.9? If anyone understood that example let me know
by Lucy Weaver 1K
Sun Jan 24, 2021 10:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Fridays Lecture Clarification
Replies: 3
Views: 38

Fridays Lecture Clarification

Did anyone understand the context of what Dr. Lavelle was explaining when he was listing the standard states for gasses, solutions, pure liquids and solids etc? I did not understand in what context this information would be useful
by Lucy Weaver 1K
Sun Jan 24, 2021 10:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to find equations
Replies: 4
Views: 18

Re: How to find equations

I mean like the balanced chemical equations you need to solve the problem
by Lucy Weaver 1K
Sun Jan 24, 2021 10:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pka, Ph, charged and neutral species
Replies: 7
Views: 46

Pka, Ph, charged and neutral species

Are these statements correct:
For an acid, when pH>pKa, the charged species is dominant
For an acid, when pH<pKa, the neutral species is dominant
For a base, when pH>pKa, the neutral species is dominant
For a base, when pH<pKa, the charged species is dominant
by Lucy Weaver 1K
Sun Jan 24, 2021 10:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to find equations
Replies: 4
Views: 18

How to find equations

How do you find the chemical equations for problems like this: HClO is a weak acid ( ka=4.0×10−8 ) and so the salt NaClO acts as a weak base. What is the pH of a solution that is 0.018 M in NaClO at 25 °C?
by Lucy Weaver 1K
Sun Jan 24, 2021 10:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Homework 2 #5
Replies: 2
Views: 16

Re: Sapling Homework 2 #5

Thank you so much, I was dividing the concentration of B by OH, not the other way around. I really appreciate it!
by Lucy Weaver 1K
Sun Jan 24, 2021 10:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Homework 2 #5
Replies: 2
Views: 16

Sapling Homework 2 #5

The Kb for an amine is 1.250×10−5. What percentage of the amine is protonated if the pH of a solution of the amine is 9.387 ? Assume that all OH− came from the reaction of B with H2O. I think I'm setting up my ice table wrong for this problem. From the pH, I calculate pOH, and from there I calculate...
by Lucy Weaver 1K
Sun Jan 24, 2021 9:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #2 week 2
Replies: 5
Views: 26

Re: Sapling #2 week 2

Thanks so much, I was dividing by .0024 instead of .128
by Lucy Weaver 1K
Sun Jan 24, 2021 9:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #2 week 2
Replies: 5
Views: 26

Sapling #2 week 2

Im not sure why I'm getting this problem wrong, the question is: The ka of a monoprotic weak acid is 0.00247. What is the percent ionization of a 0.128 M solution of this acid? I first set up the ice table for the week acid, so HA +H2O --> A- + H I .128 - 0 0 C -x - +x +x E .128-x - x x Then, I solv...
by Lucy Weaver 1K
Sat Jan 16, 2021 6:41 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Temperature
Replies: 12
Views: 81

Re: Temperature

Yes I believe you would have to write two different equations, if there was a certain temperature required for equilibrium and the temperature suddenly changed, you would have to calculate the k and q values for temperature change.
by Lucy Weaver 1K
Sat Jan 16, 2021 6:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Week 1 Sapling #5
Replies: 2
Views: 52

Re: Week 1 Sapling #5

I think that we are able to manipulate equilibrium constants like this because regardless of concentration, equilibrium constants for a particular equation will always be constant. So if we are able to manipulate equations to eventually end up with the same products and reactants, we know that their...
by Lucy Weaver 1K
Sat Jan 16, 2021 6:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw constant
Replies: 25
Views: 62

Re: Kw constant

Since water is in large excess, we assume its concentration to be relatively unchanged. That is, we aren't able to detect the change in water since it's probably something in the decimal units so it is essentially undetectable.
by Lucy Weaver 1K
Sat Jan 16, 2021 6:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table and Molarity units
Replies: 18
Views: 71

Re: ICE table and Molarity units

I think that if it asks for the final concentration then it is assuming your final answer must be in mol/L, but if it asks for the final molar concentration I think keeping it in moles is fine. I usually always convert thought if it gives me a measurement for volume
by Lucy Weaver 1K
Thu Jan 14, 2021 7:30 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sapling question 9
Replies: 5
Views: 63

Sapling question 9

Can anyone help me with question 9 on sapling? I keep getting a concentration of a negative value for x and I'm not sure what I'm doing wrong. If someone can share how they did this problem thatd be great thx!
by Lucy Weaver 1K
Sun Jan 10, 2021 11:50 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Module 2
Replies: 2
Views: 65

Module 2

Can anyone explain how to do this question?
by Lucy Weaver 1K
Sun Jan 10, 2021 10:56 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Video Module question 19
Replies: 3
Views: 25

Video Module question 19

19. Calculate the reaction quotient, QC, from the following equilibrium data collected in a 3.00 L sealed reaction vessel for the reaction: AsH3 (g) ⇌ As (s) + H2 (g) AsH3 = 5.55 x 10^-4 mol, As = 3.31 x 10^-3 mol, H2 = 1.23 x 10^-3 mol. I keep getting .006 for this question, I'm dividng (1.23 x 10^...
by Lucy Weaver 1K
Sun Jan 10, 2021 8:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: identifying solids and non homogeneous reactant/product
Replies: 4
Views: 13

Re: identifying solids and non homogeneous reactant/product

I think most of the time its labeled in the equation after the element (co2 will be listed as CO2 (g) in an equation) as (aq), (l), (s), or (g). I dont beleive were expected to know.
by Lucy Weaver 1K
Sun Jan 10, 2021 8:05 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: aqueous solutions
Replies: 9
Views: 49

aqueous solutions

cam elements in an equation labeled (aq) also not be included in the equilibrium constant equation?
by Lucy Weaver 1K
Sun Jan 10, 2021 8:03 pm
Forum: Student Social/Study Group
Topic: Group Me
Replies: 6
Views: 43

Group Me

Is there a group me for this class
by Lucy Weaver 1K
Sun Dec 13, 2020 9:13 am
Forum: Trends in The Periodic Table
Topic: When to use size and when to use electronegativity in respect to determining acidity
Replies: 1
Views: 19

When to use size and when to use electronegativity in respect to determining acidity

Does anyone know when we should use the size of an atom to determine acidity and when to use its electronegativity? I know that as ions get bigger, their bond to hydrogen becomes weaker since its a longer bond which makes this compound more acidic. Also, when Hydrogen is bound to two atoms, the more...
by Lucy Weaver 1K
Sun Dec 13, 2020 9:09 am
Forum: *Shrodinger Equation
Topic: Wave properties of electron diffraction
Replies: 6
Views: 58

Re: Wave properties of electron diffraction

One of the UA's in her review session posted this which I thought was helpful in understanding the concept
by Lucy Weaver 1K
Sun Dec 13, 2020 9:05 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Determining Which is More Acidic Between 2 Weak Acids
Replies: 3
Views: 50

Re: Determining Which is More Acidic Between 2 Weak Acids

I think you should always start by drawing out the lewis structures and seeing which molecules the partial charge lies on and keep in mind the electronegativity of the molecules(electron pulling ability)
by Lucy Weaver 1K
Sun Dec 13, 2020 9:03 am
Forum: Calculating the pH of Salt Solutions
Topic: Solving PH/PoH
Replies: 11
Views: 98

Re: Solving PH/PoH

It helps me to remember these rules
pH: -log of (H+ concentration)
pH: 14-pOH
pOH:14-pH
pOH: -log of (OH- concentration)
H+: 10^-pH
OH-: 10^-pOH
by Lucy Weaver 1K
Sun Dec 13, 2020 8:59 am
Forum: Identifying Acidic & Basic Salts
Topic: Question 7 sapling
Replies: 5
Views: 25

Question 7 sapling

IS there an easier way to distinguish these salts acidic or basic? The solution for this question is sort of confusing
by Lucy Weaver 1K
Sat Dec 05, 2020 7:58 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Final Exam Material [ENDORSED]
Replies: 7
Views: 128

Re: Final Exam Material [ENDORSED]

I don't think we will need to calculate it but my TA always says that anything Dr. Lavelle says in lecture is fair game on tests.
by Lucy Weaver 1K
Sat Dec 05, 2020 7:56 pm
Forum: Lewis Acids & Bases
Topic: How do you tell if something is a strong base?
Replies: 3
Views: 23

How do you tell if something is a strong base?

I know that group 1 metal hydroxides and group 1/2 metal oxides are strong bases, but does anyone know the chemical properties that make them such?
by Lucy Weaver 1K
Sat Dec 05, 2020 7:51 pm
Forum: Bronsted Acids & Bases
Topic: Do acids always list hydrogens as the first element in a molecule?
Replies: 3
Views: 22

Do acids always list hydrogens as the first element in a molecule?

In the textbook it says that acids contain hydrogen atoms and always list them as the first element, but are there cases where this is not true?
by Lucy Weaver 1K
Sat Dec 05, 2020 7:25 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Pka and Ka
Replies: 6
Views: 53

Pka and Ka

Can anyone explain the difference between Pka and Ka values.
by Lucy Weaver 1K
Sat Dec 05, 2020 7:25 pm
Forum: Bronsted Acids & Bases
Topic: Relative strength of acids and bases
Replies: 2
Views: 23

Relative strength of acids and bases

Hi, Can anyone explain the equation Dr. Lavelle went over in lecture to calculate weak acids/bases, I understand that if Ka is a large value this means that the acid is strong but I'm a little unsure of what the variables are and what values you need to calculate this? ka = [A-][H+]/[AH].
by Lucy Weaver 1K
Sat Nov 28, 2020 6:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sapling question 18
Replies: 2
Views: 34

sapling question 18

does anyone understand why in this question where H2C(Cx)CH2, x= a whole number, why when x is even the Hydrogen atoms are coplanar but when x is odd, the hydrogen atoms lie on perpendicular planes? I'm not sure what this means or why only two of the hydrogen strcutures are oriented this way. If som...
by Lucy Weaver 1K
Sat Nov 28, 2020 5:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Delocalized Pi Bond
Replies: 5
Views: 17

Re: Delocalized Pi Bond

Sorry disregard the above answer, I think it just has to do with resonance structures and whether or not double/triple bonds can be moved around.
by Lucy Weaver 1K
Sat Nov 28, 2020 5:04 pm
Forum: Hybridization
Topic: Question 11 sapling
Replies: 5
Views: 18

Re: Question 11 sapling

Okay thanks everyone that makes sense, I did'nt realize it was only wanting us to look at phosphorus.
by Lucy Weaver 1K
Sat Nov 28, 2020 5:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Delocalized Pi Bond
Replies: 5
Views: 17

Re: Delocalized Pi Bond

I think this has to do with when atoms have unhybridized p orbitals, like in the example he did in class for Benzene (C6H6). In this molecule, each carbon atom has a unhybridized p orbital, so each carbon contributes one electron to this ring of carbons. The unhybridized p orbitals make the C-C bond...
by Lucy Weaver 1K
Sat Nov 28, 2020 4:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: pi and sigma bonds
Replies: 17
Views: 123

Re: pi and sigma bonds

Usually how I determine it is using the fact that a sigma bond is a single bond, and a double bond has one pi bond and one sigma bond. So if a molecule has 3 single bonds and one double bond, it would have 4 sigma bonds and 1 pi bond. Hope that helps.
by Lucy Weaver 1K
Sat Nov 28, 2020 4:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Weeks 7-8 #7
Replies: 3
Views: 35

Re: Sapling Weeks 7-8 #7

I beleive that since the Cl molecules have a -1 charge because of their 3 lone pair electrons, the shape of the molecule is asymmetrical which means that the dipole moments do not cancel. It might also have something to dow with the fact that the electronegativity difference between Cl and C is high...
by Lucy Weaver 1K
Sat Nov 28, 2020 4:51 pm
Forum: Dipole Moments
Topic: dipole moments
Replies: 4
Views: 18

dipole moments

How do you determine whether or not an atom has a high dipole moment
by Lucy Weaver 1K
Sat Nov 28, 2020 4:45 pm
Forum: Hybridization
Topic: hybridization
Replies: 5
Views: 61

Re: hybridization

During one of his lectures he did have a slide which described that if you have a trigonal bipyramidal atom (5 regions of electron density), you need to invoke 5dsp3 hybridization(1 s orbital, 3 p orbitals and 1 d orbital). And if you have an octahedral atom(6 regions of electron density), you need ...
by Lucy Weaver 1K
Sat Nov 28, 2020 4:37 pm
Forum: Hybridization
Topic: Question 11 sapling
Replies: 5
Views: 18

Question 11 sapling

Could someone explain why the hybridization if p4o6 is sp3? I understand all the rest of the atoms in this question except for this one. Thanks in adance
by Lucy Weaver 1K
Sun Nov 22, 2020 4:29 pm
Forum: Student Social/Study Group
Topic: CHEM 14B Time Conflict
Replies: 13
Views: 163

Re: CHEM 14B Time Conflict

I beleive on My UCLA it says that the lectures are recorded again, obviously not the lab but there are so many lab's hopefully you can find a time that works.
by Lucy Weaver 1K
Sun Nov 22, 2020 4:28 pm
Forum: Student Social/Study Group
Topic: grade worries
Replies: 110
Views: 1228

Re: grade worries

I am also worried, will probably end up taking the class for P/NP instead of a letter grade
by Lucy Weaver 1K
Sun Nov 22, 2020 4:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 7 Sapling
Replies: 12
Views: 173

Re: Week 7 Sapling

I beleive that they're both due next Sunday.
by Lucy Weaver 1K
Sun Nov 22, 2020 4:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Scores
Replies: 28
Views: 217

Re: Midterm 2 Scores

I think within this week, although it could be later due to the holiday.
by Lucy Weaver 1K
Sun Nov 22, 2020 4:23 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving week lectures
Replies: 5
Views: 63

Thanksgiving week lectures

Does anyone know if we will be having lectures/discussions on Wednesday and Friday of thanksgiving week?
by Lucy Weaver 1K
Thu Nov 12, 2020 2:55 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Finding Oxidation number
Replies: 1
Views: 24

Finding Oxidation number

Have we learned how to find the oxidation number of an element yet? There's a question that asks us to on sapling and I don't remember Dr. Lavelle going over this is lecture
by Lucy Weaver 1K
Thu Nov 12, 2020 2:54 pm
Forum: Ionic & Covalent Bonds
Topic: Dipole-Dipole and Ion-Dipole
Replies: 1
Views: 13

Dipole-Dipole and Ion-Dipole

How should I go about telling the difference between Dipole-Dipole and Ion-Dipole interactions?
by Lucy Weaver 1K
Thu Nov 12, 2020 2:49 pm
Forum: Ionic & Covalent Bonds
Topic: Hydrogen Bond Homework Question
Replies: 3
Views: 15

Re: Hydrogen Bond Homework Question

Hydrogen bonds can only occur with a N,O, or F atom which must have a hydrogen atom covalently bonded to the electronegative atom. This atom must also have another electronegative atom bound to hydrogen close by with an available lone pair. It helps me to draw the molecules out and see what can bond...
by Lucy Weaver 1K
Thu Nov 12, 2020 2:44 pm
Forum: Ionic & Covalent Bonds
Topic: sapling homework question 12
Replies: 4
Views: 29

Re: sapling homework question 12

Thanks everyone that makes sense!
by Lucy Weaver 1K
Thu Nov 12, 2020 2:40 pm
Forum: Octet Exceptions
Topic: Octet Rule Exceptions
Replies: 20
Views: 214

Octet Rule Exceptions

I know in class we were taught that H,He, Li, and Be are exceptions to the octet rule as well as group 13 elements, but are there any otheres? in the sapling homework I learned that phosphate is also an exception because it can have 10 (5 shared) if it makes the formal charge lesser. I'm curious to ...
by Lucy Weaver 1K
Wed Nov 11, 2020 8:19 pm
Forum: Ionic & Covalent Bonds
Topic: sapling homework question 12
Replies: 4
Views: 29

sapling homework question 12

I understand why the fourth option is a hydrogen bond, but I don't understand why the first or second option isn't, can anyone explain?
by Lucy Weaver 1K
Sun Nov 08, 2020 7:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Question Count
Replies: 17
Views: 134

Re: Midterm 2 Question Count

I've heard it will be more questions that are shorter
by Lucy Weaver 1K
Sun Nov 08, 2020 7:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Format
Replies: 7
Views: 41

Re: Midterm 2 Format

I've heard it will be the same format but it will be more questions that are shorter.
by Lucy Weaver 1K
Sun Nov 08, 2020 7:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Scores
Replies: 28
Views: 272

Re: Midterm Scores

You can't review your actual midterm but if you ask your TA to go over concepts that you got wrong mine helped me with that.
by Lucy Weaver 1K
Sun Nov 08, 2020 7:49 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Solutions
Replies: 4
Views: 42

Re: Midterm Solutions

You can ask your TA to go over specific concepts that you missed! But they will not show you specific questions
by Lucy Weaver 1K
Sun Nov 08, 2020 7:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Posting Screenshots on Chem Community
Replies: 3
Views: 32

Re: Posting Screenshots on Chem Community

I always just drag the screenshot from my desktop into the text section and it will post it automatically when you post your question
by Lucy Weaver 1K
Sun Nov 08, 2020 7:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2
Replies: 3
Views: 60

Re: Midterm 2

I've heard it will be more than 12 questions this time.
by Lucy Weaver 1K
Sun Nov 08, 2020 7:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Curve?
Replies: 12
Views: 140

Re: Midterm Curve?

In past classes it has not been curved so I dont think it will be this year.
by Lucy Weaver 1K
Sun Nov 01, 2020 11:07 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Sapling #21
Replies: 4
Views: 52

Re: Sapling #21

It helps me to go through it with the chart that Dr. Lavelle showed us in his lecture Friday of week 3. So for example, if it tells you that n=3, you know that there are three subshells (s,p, and d). In the s subshell, there are two spots for electrons, in the p subshell, there are 6 spots for elect...
by Lucy Weaver 1K
Sun Nov 01, 2020 11:02 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: sapling 13
Replies: 7
Views: 67

Re: sapling 13

It helps me to go through it with the chart that Dr. Lavelle showed us in his lecture Friday of week 3. So for example, if it tells you that n=3, you know that there are three subshells (s,p, and d). In the s subshell, there are two spots for electrons, in the p subshell, there are 6 spots for elect...
by Lucy Weaver 1K
Sun Nov 01, 2020 10:50 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nuclear charge
Replies: 1
Views: 11

Nuclear charge

What determines which elements have a higher nuclear charge than others?
by Lucy Weaver 1K
Sun Nov 01, 2020 10:30 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital energy
Replies: 5
Views: 46

Orbital energy

Could someone explain why 4s is refered to as having lower energy than 3d?
by Lucy Weaver 1K
Tue Oct 27, 2020 12:36 pm
Forum: Properties of Light
Topic: textbook problem 1A 15
Replies: 2
Views: 44

textbook problem 1A 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 Does anyone have any advice on how to start this problem? does it have to d...
by Lucy Weaver 1K
Sat Oct 24, 2020 9:37 pm
Forum: DeBroglie Equation
Topic: How to convert from joules to volts
Replies: 5
Views: 51

How to convert from joules to volts

Problem 22 in sapling homework asks us to convert from Joules to Volts, does anyone know how to do this calculation?
by Lucy Weaver 1K
Sat Oct 24, 2020 9:36 pm
Forum: Properties of Electrons
Topic: Question 12 on sapling week 2
Replies: 4
Views: 57

Re: Question 12 on sapling week 2

Thanks all that makes so much sense!
by Lucy Weaver 1K
Sat Oct 24, 2020 9:02 pm
Forum: Properties of Electrons
Topic: Question 12 on sapling week 2
Replies: 4
Views: 57

Question 12 on sapling week 2

Does anyone know why the solution for this problem requires you to use 1.0974 * 10^7 as R instead of what reybergs constant is listed on the equation sheet? Origionally I had done 1/lamba=3.28984 × 1015 Hz*(1/n1^2-1/n2^2) But the solutions say to do 1/lamba=1.0974 * 10^7 m^-1*(1/n1^2-1/n2^2) I am un...
by Lucy Weaver 1K
Sat Oct 24, 2020 12:45 pm
Forum: Properties of Electrons
Topic: How to convert from Energy per photon to Energy per electron
Replies: 2
Views: 53

How to convert from Energy per photon to Energy per electron

For question 25 on the sapling homework, I know how to find the energy per photon but I am unsure of how to use this to find the energy per electron, don't we need to know the velocity of electron for this?

Any help with this question would be great, thanks!
by Lucy Weaver 1K
Fri Oct 23, 2020 8:39 pm
Forum: Properties of Electrons
Topic: Sapling Homework Week 2 question 8
Replies: 3
Views: 50

Sapling Homework Week 2 question 8

When this question asks for the values of n for the beginning and ending energy levels of the electron, I do not really understand what it means, how should I go about starting this problem?
by Lucy Weaver 1K
Fri Oct 23, 2020 7:15 pm
Forum: Properties of Electrons
Topic: sapling homework question 6
Replies: 3
Views: 17

Re: sapling homework question 6

Hi! For this question, I used the Rydberg equation (v= R(1/n1^2)-(1/n2^2)) to find the frequencies between levels 6 and 1 and levels 6 and 5. For n=6 to n=1, the frequency is (3.29x10^15)(1^(-2) - 6^(-2) = 3.20x10^15 Hz. Using the same equation, I found that the frequency of the n=6 to n=5 transiti...
by Lucy Weaver 1K
Fri Oct 23, 2020 6:21 pm
Forum: Properties of Electrons
Topic: sapling homework question 6
Replies: 3
Views: 17

sapling homework question 6

I am having trouble understanding what I am doing wrong for this problem. I understand the first question, but for the range of wavelengths I keep getting it wrong. I found the difference between n1 and n6 to be 2.12 * 10^-18, and the difference between n5 and n6 to be 2.66*106-20. I then converted ...
by Lucy Weaver 1K
Fri Oct 23, 2020 3:52 pm
Forum: Properties of Light
Topic: Sapling Homework week 2 problem 5
Replies: 11
Views: 137

Sapling Homework week 2 problem 5

HI! I'm having a lot of trouble solving the 5th problem on sapling. I muplipled planks constant by the speed of light, got 1.98644582 × 10-25 m3 kg / s2, then divided that by 9.33 * 10^-4 to get E. I found that E= 2.13 *10^-22.Then I divided that by 100 to turn it from centimeters to meters. I got 2...
by Lucy Weaver 1K
Sat Oct 10, 2020 6:26 pm
Forum: Empirical & Molecular Formulas
Topic: Calculating Atomic Mass of a Molecule
Replies: 9
Views: 78

Re: Calculating Atomic Mass of a Molecule

I usually use the exact values provided on a periodic table, for exams I beleive we will be given a periodic table so we should just use the exact values from that and then round our answers accordingly depending on what decimal place is specified.
by Lucy Weaver 1K
Sat Oct 10, 2020 6:20 pm
Forum: Limiting Reactant Calculations
Topic: Question 10 homework
Replies: 9
Views: 152

Question 10 homework

I am a little confused about how to balance the reaction for the last question on the homework, it does not seem to be working out

Right now I have the chemical equation as
C4H8O +C3H7Br +Mg --> C7H16O

It doesn't seem to me that this equation is able to be balanced
by Lucy Weaver 1K
Thu Oct 08, 2020 4:33 pm
Forum: Empirical & Molecular Formulas
Topic: difference between empirical and molecular
Replies: 15
Views: 70

difference between empirical and molecular

How do you know if the empirical and molecular formula are equal?
by Lucy Weaver 1K
Thu Oct 08, 2020 4:28 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect post quiz question
Replies: 1
Views: 37

Photoelectric Effect post quiz question

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. I know how to find the minimum energy needed to produce this effect, but I am having trouble answering this question: If molybdenum is irradiated with 194 n...
by Lucy Weaver 1K
Thu Oct 08, 2020 4:23 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect question help
Replies: 1
Views: 21

Photoelectric Effect question help

Im having a lot of trouble with this question,

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1.

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