## Search found 90 matches

Fri Jan 15, 2021 11:34 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: saplingQ. 2
Replies: 4
Views: 38

### Re: saplingQ. 2

I think I actually may have found your mistake, as well as mine. After watching today's lecture, I realized that the denominator for the percentage ionization equation is supposed to be the initial concentration of the acid. Once I acknowledged this, I was able to get the correct answer.
Fri Jan 15, 2021 11:33 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1
Replies: 7
Views: 48

### Re: Midterm 1

I was wondering the same thing! I am assuming that Dr. Lavelle may include some thermochemistry on midterm 1 because we start that next week, but that is just a guess.
Fri Jan 15, 2021 9:52 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: saplingQ. 2
Replies: 4
Views: 38

### Re: saplingQ. 2

I had trouble with this problem too! I found it helpful to write out the equation for the deprotonation of an acid. HA -> A- + H+. From this step, I used an ICE table to determine the x-value, and thus the concentrations of each element. From then, I plugged those values into the equation for percen...
Fri Jan 15, 2021 9:37 am
Forum: Student Social/Study Group
Topic: Exam Changes
Replies: 10
Views: 39

### Re: Exam Changes

On that note, does anyone know if we will join a Zoom with our TA during the exam time for the proctoring session?
Thu Jan 14, 2021 8:31 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 12
Views: 44

### ICE Tables

How do we know whether the change in the ICE tables are +x or -x? I have seen examples and homework problems where it might be +x but I have also seen examples where it might be -x. I am referring to the reactants in the ICE table, by the way.
Wed Jan 13, 2021 6:07 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: What is the Conjugate Seesaw
Replies: 10
Views: 49

### Re: What is the Conjugate Seesaw

I kind of like to draw it out and physically visualize a seesaw. When a stronger acid is present, then that means that the acid's conjugate base will be weaker. Vice versa for a stronger base. When a stronger base is present, then that means that the base's conjugate acid will be weaker.
Sun Jan 10, 2021 6:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling HW 1 Question 2
Replies: 5
Views: 25

### Re: Sapling HW 1 Question 2

I would re-do your ICE table because when I did it I got x=0.05429. When filling out your ICE table, be sure that for SO3 the change in equilibrium is -2x, and for SO2 it is +2x and for O2 it is +x.
Wed Jan 06, 2021 12:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Would equilibrium favor resonance?
Replies: 3
Views: 15

### Re: Would equilibrium favor resonance?

Yes, because equilibrium favors the most stable aspect of the reaction I believe it would favor resonance because resonance also favors the more stable drawing.
Wed Jan 06, 2021 12:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Self-Test 5G.1A
Replies: 4
Views: 25

### Self-Test 5G.1A

The answer to self-test 5G.1A includes water into the equilibrium constant. My TA went over this, but I just wanted to ensure that I fully understand. Water is included into the equilibrium constant because water is in its gaseous phase. I would appreciate it if someone could confirm this.
Tue Jan 05, 2021 5:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Meeting Passcode for Michael's UA Workshop
Replies: 1
Views: 33

### Meeting Passcode for Michael's UA Workshop

For anyone trying to get into Michael's UA Workshop, do you know the passcode? When I try to join the Zoom link it asks me to input a Meeting Passcode.
Tue Jan 05, 2021 4:18 pm
Forum: Student Social/Study Group
Topic: Learning Sessions
Replies: 24
Views: 91

### Re: Learning Sessions

I recommend attending as many as you can! They were super helpful for me last quarter, especially since I was exposed to many different practice problems.
Tue Jan 05, 2021 4:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Can I do hw if I don't have sapling yet?
Replies: 16
Views: 96

### Re: Can I do hw if I don't have sapling yet?

You should be able to choose a free trial on Sapling. I was able to use that option as well.
Sat Dec 12, 2020 7:23 pm
Forum: Bronsted Acids & Bases
Topic: determining cations or anions
Replies: 4
Views: 39

### Re: determining cations or anions

are we supposed to know how to do problems like J17a (in the textbook) on the final? I am very confused about how this would be solved :/ In each of the following salts, either the cation or the anion is a weak acid or a weak base in water. Write the chemical equation for the proton transfer reacti...
Sat Dec 12, 2020 7:17 pm
Forum: Sigma & Pi Bonds
Topic: CO2 sigma/pi bond composition
Replies: 3
Views: 30

### Re: CO2 sigma/pi bond composition

I believe the pi bond composition would just be (C2p, O2p) because p-orbitals are the ones able to take part in pi bonds.
Fri Dec 11, 2020 7:35 pm
Forum: Conjugate Acids & Bases
Topic: Amphoteric compounds memorization
Replies: 1
Views: 16

### Re: Amphoteric compounds memorization

I think if you memorize the trends on the periodic table, then you would be able to decipher which ones are amphoteric compounds.
Thu Dec 10, 2020 12:33 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: LiCl vs. NaCl Boiling Point
Replies: 1
Views: 18

### Re: LiCl vs. NaCl Boiling Point

I think NaCl has a higher boiling point because there is a bigger difference in electronegativity, making the NaCl molecule more ionic than the LiCl molecule. Thus, resulting it NaCl having a higher boiling point.
Thu Dec 10, 2020 12:17 pm
Forum: Balancing Chemical Reactions
Topic: Textbook L.35
Replies: 1
Views: 28

### Re: Textbook L.35

If you look on Dr. Lavelle's website, there is a file titled "Solution Manual Errors 7th Edition," and there is an error in which one of these chemical reactions is written. So if you were having trouble balancing it, I think this may have contributed to that struggle. Here is the error: i...
Thu Dec 10, 2020 12:12 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Protonation
Replies: 4
Views: 35

### Re: Protonation

This means that strong acids fully deprotonate (meaning they give away a proton) and strong bases protonate (meaning they accept a proton).
Thu Dec 10, 2020 12:10 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate of Strong Acids/Bases
Replies: 1
Views: 17

### Re: Conjugate of Strong Acids/Bases

I think it is because strong acids and bases fully dissociate in aqueous solutions. So, these strong acids and bases will not be accounted for in equilibrium.
Thu Dec 10, 2020 12:08 pm
Forum: Student Social/Study Group
Topic: Anxiety
Replies: 36
Views: 192

### Re: Anxiety

Take a breather. If you are anxious with regards to the final (as I am sure most of us are), I would recommend taking a few moments to write down what you do know and what you don't know. I personally like to take the time to go through each learning objective on all of the outlines and make note of...
Thu Dec 10, 2020 12:05 pm
Forum: Student Social/Study Group
Topic: Final
Replies: 18
Views: 105

### Re: Final

I think some questions will come directly from the textbook, but I assume that most of the questions on the final exam will simply be derived from textbook problems.
Thu Dec 10, 2020 11:17 am
Forum: Conjugate Acids & Bases
Topic: HW 6C.17
Replies: 3
Views: 21

### Re: HW 6C.17

Darlene Lien 1B wrote:Hi, I think you're supposed to look at Table 6C.2 to get the kB values!

Ahh, okay! Thanks so much!! Do you, by any chance, know if those values will be provided to us on the final exam if we encounter a question similar to this one?
Thu Dec 10, 2020 11:11 am
Forum: Conjugate Acids & Bases
Topic: HW 6C.17
Replies: 3
Views: 21

### HW 6C.17

For 6C.17, the question asks us to identify which is the stronger base: BrO- (hypobromite ion) or C17H19O3N (morphine). When I consulted the answer key, it came about answering this question by calculating the pKb values, but the question doesn't offer the Kb values. Are we expected to know the Kb v...
Thu Dec 10, 2020 9:14 am
Forum: Bronsted Acids & Bases
Topic: Why is formic acid stronger than acetic acid?
Replies: 2
Views: 21

### Re: Why is formic acid stronger than acetic acid?

The methyl group (-CH3) in acetic acid inductively donates electron density to the COOH. This makes the O-H bond less likely to break. Formic acid does not have an electron donating group, so its O-H bond is slightly more acidic. So would it be a good rule of thumb that when a methly group (-CH3) i...
Thu Dec 10, 2020 9:11 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: formic and acetic acid
Replies: 4
Views: 54

### Re: formic and acetic acid

Acetic acid is CH3COOH, and formic acid is HCOOH. Comparing these two acids, formic acid would be the stronger acid because it can more easily lose its Hydrogen (H+) to a base. This is because in acetic acid, the CH3 in acetic acid is an electron-donating group, meaning that CH3 inductively donates ...
Thu Dec 10, 2020 9:05 am
Forum: Industrial Examples
Topic: Chemotherapy
Replies: 18
Views: 376

### Re: Chemotherapy

On almost every UA sheet from Week 9, there was a question about cisplatin. I think Dr. Lavelle spent a significant amount of time explaining cisplatin (and transplatin), so I would expect it to show up on the final in one way or another. On almost every UA sheet from Week 9, there was a question a...
Thu Dec 10, 2020 9:00 am
Forum: Administrative Questions and Class Announcements
Topic: FINAL EXAM QUESTIONS
Replies: 24
Views: 276

### Re: FINAL EXAM QUESTIONS

I heard that some of the questions will come from the final, but I believe most (if not, all) will be derived from the textbook problems. I would recommend working through every single textbook problem and ensuring that you understand how to go about answering it, and I think you will be set for the...
Wed Dec 09, 2020 7:59 pm
Forum: Biological Examples
Topic: Final Exam
Replies: 8
Views: 118

### Re: Final Exam

I think it would be helpful to know these biological applications:
Cr - assist insulin in control of blood sugar
Fe - hemoglobin, myoglobin, electron transfer in the oxidation of carbohydrates, proteins, and fats (respiratory chain)
Co - vitamin b12
Mn, Ni, Cu, Zn - enzymatic functions
Wed Dec 09, 2020 2:36 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Chem Final
Replies: 7
Views: 60

### Re: Chem Final

Joshua Eidam 3D wrote:Does anyone know what the format of the test is going to be like as well as how long the test is going to be?

It is going to follow the same format of the previous midterms. It will be 30 multiple choice questions, and it will be 1 hour and 30 minutes (plus 5 extra minutes).
Wed Dec 09, 2020 12:38 pm
Forum: Hybridization
Topic: Hybridization Orbitals
Replies: 1
Views: 25

### Hybridization Orbitals

I am having a bit of trouble understanding hybridization orbitals. So, in hybridizations orbitals, are lower level electrons (say in the 2s state, for example) "promoted" to a higher energy level (such as 2p), and is that how they arise from atomic orbitals? Also, how would we go about dra...
Wed Dec 09, 2020 12:32 pm
Forum: Bronsted Acids & Bases
Topic: Respiratory Acidosis
Replies: 1
Views: 33

### Re: Respiratory Acidosis

Pg. 506 of the textbook goes over this. So, respiratory acidosis is a result when respiration decreases from conditions such as asthma, pneumonia, and emphysema, and even from inhaling smoke. These conditions raise the concentration of CO2 in the blood, and hence the concentration of H2CO3 is raised...
Wed Dec 09, 2020 10:55 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook 6C.19
Replies: 3
Views: 28

### Re: Textbook 6C.19

In part (a) you would consider the atomic radius/bond length, since it is a binary acid. However, for the rest of the question, you would consider electronegativity because it is a more complex acid.
Wed Dec 09, 2020 10:51 am
Forum: Student Social/Study Group
Topic: lecture bruincast #29 problem
Replies: 10
Views: 76

### Re: lecture bruincast #29 problem

I had a similar problem, and another student suggested to me to log into the VPN and it worked perfectly from there.
Wed Dec 09, 2020 10:44 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Overall Rxn K
Replies: 2
Views: 21

### Re: Overall Rxn K

I think Dr. Lavelle discussed this to highlight the basic concept that the overall Ka value is the product of Ka1 and Ka2. So, I believe that you are going about performing this correctly. But I also think that the biggest takeaway from this was that Ka1>Ka2>Ka3 because it harder to deprotonate a ne...
Wed Dec 09, 2020 10:41 am
Forum: Calculating the pH of Salt Solutions
Topic: Titration Diagram
Replies: 4
Views: 61

### Re: Titration Diagram

I believe they just highlight data points, so that when you draw the curve with all of your plotted data you would better be able to identify the stoichiometric point. I think those points you are asking about specifically are just the pH of solution as they correspond to the volume of the solution.
Wed Dec 09, 2020 10:39 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: week 10 Sapling Q12
Replies: 2
Views: 28

### Re: week 10 Sapling Q12

The strength of the acid would decrease as the amount of Oxygen atoms in the acid decreases because there are less Oxygen atoms to stabilize the acid. Thus, the acid would be least comfortable giving up its H+ ion because it has less Oxygen atoms to stabilize the acid after it has given up the H+.
Wed Dec 09, 2020 10:34 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acidity Stronger
Replies: 3
Views: 38

### Re: Acidity Stronger

You would typically refer to atomic radius/bond length when looking at binary acids, such as H-F, H-Cl, H-Br, and H-I. However, you would refer to electronegativity for acids that read like HClO4, H2SO4, and HNO3.
Wed Dec 09, 2020 10:25 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH to pOH
Replies: 8
Views: 60

### Re: pH to pOH

Heather Szeszulski 1I wrote:what is pOH? i am a little confused

pOH is a measure of the concentration of the hydroxide ion [OH-].
Just know that [OH-}*[H+]=1.00*10^-14, and pOH+pH=14.00
Here is a site that explains it in more detail: https://courses.lumenlearning.com/chemi ... h-concept/
Mon Dec 07, 2020 10:07 am
Forum: Administrative Questions and Class Announcements
Topic: Lecture Videos Not Playing [ENDORSED]
Replies: 16
Views: 128

### Lecture Videos Not Playing[ENDORSED]

When trying to watch today's lecture, I was prompted with Error Code: 232001. Has this happened to anyone else? If so, is there another way we can access today's lecture?
Sat Dec 05, 2020 9:46 pm
Forum: Lewis Acids & Bases
Topic: Application to the Period Table
Replies: 6
Views: 41

### Re: Application to the Period Table

In Friday's lecture, Dr. Lavelle noted that the alkali metals and alkaline earth metals (excluding Beryllium) typically give rise to bases (or basic oxides), whereas elements on the right hand side of the periodic table typically give rise to acids (or acidic oxides). However, amphoteric elements a...
Sat Dec 05, 2020 9:39 pm
Forum: Naming
Topic: Diatomic Molecules
Replies: 4
Views: 43

### Re: Diatomic Molecules

The prefixes do not apply to elements outside of the coordination sphere (or outside of the brackets). I think the only way to indicate that it is dichloride is to look at the charge of the coordination compound.
Sat Dec 05, 2020 9:37 pm
Forum: Bronsted Acids & Bases
Topic: CH3COOH vs HCl
Replies: 2
Views: 31

### Re: CH3COOH vs HCl

To be considered a strong acid, the acid must completely deprotonate. Thus, CH3COOH is considered to be a weak acid because it doesn't completely give up its protons, as it only gives up one H+ ion. However, HCl is considered to be a strong acid because it completely deprotonates in an aqueous solut...
Sat Dec 05, 2020 9:35 pm
Forum: Lewis Acids & Bases
Topic: Application to the Period Table
Replies: 6
Views: 41

### Re: Application to the Period Table

In Friday's lecture, Dr. Lavelle noted that the alkali metals and alkaline earth metals (excluding Beryllium) typically give rise to bases (or basic oxides), whereas elements on the right hand side of the periodic table typically give rise to acids (or acidic oxides). However, amphoteric elements ar...
Sat Dec 05, 2020 9:33 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acid
Replies: 4
Views: 52

### Re: Lewis Acid

I believe you are right with respect that Lewis acids accept electrons. With regards to the proton, I believe that acids produce hydrogen ions (which would be the protons) in solution because it reacts with the water molecules by giving a proton to them. This site speaks more on this: https://www.ch...
Sat Nov 28, 2020 6:16 pm
Forum: Sigma & Pi Bonds
Topic: sapling #15
Replies: 24
Views: 134

### Re: sapling #15

Sigma bonds are single bonds and pi bonds are the additional bonds that build on top of sigma bonds. So, for example, a double bound would have 1 sigma bond and 1 pi bond. Also, a triple bond would have 1 sigma bond and 3 pi bonds. It helps to think of it as the sigma bond being the initial first bo...
Fri Nov 27, 2020 11:06 pm
Forum: Student Social/Study Group
Topic: Sampling Give Up Option
Replies: 12
Views: 95

### Re: Sampling Give Up Option

If you give up on a question, you will lose the points available for that question. I'd recommend just attempting the question as many times as you need. Not only will you keep those easy points, but you'd also exercise your thinking which would eventually be beneficial when studying for the final e...
Fri Nov 27, 2020 11:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape Sheet
Replies: 7
Views: 77

### Re: Shape Sheet

I find that this one organizes it well: https://mmstcchemistry.weebly.com/uploa ... ometry.pdf
Fri Nov 27, 2020 11:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Outlines for the Final
Replies: 11
Views: 97

### Re: Outlines for the Final

I would expect all outlines to be covered on the final. Best of luck studying! :)
Sun Nov 22, 2020 3:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity of BrF3
Replies: 6
Views: 52

### Re: Polarity of BrF3

I believe that since there are lone pairs present on Br the dipole moments don't entirely cancel out, so it would be a polar molecule.
Sun Nov 22, 2020 3:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Problem of viewing the lecture
Replies: 9
Views: 47

### Re: Problem of viewing the lecture

I think it would help to restart your computer. Or maybe you could try using a different browser. I found that using Chrome is better than using Safari, if you have a Macbook.
Fri Nov 20, 2020 1:42 pm
Forum: Lewis Structures
Topic: Electron Density
Replies: 14
Views: 113

### Re: Electron Density

Electron density refers to the probability that an atom would be found in any given region of an orbital. And to answer your second question, I believe that any area where an electron could be found would be considered a region of electron density.
Fri Nov 20, 2020 1:41 pm
Forum: Ionic & Covalent Bonds
Topic: Which is strongest bond
Replies: 9
Views: 97

### Re: Which is strongest bond

Since F is the largest element, it would have a greater atomic radius, and thus greater bond length, so the bond would be weaker.
Fri Nov 20, 2020 1:39 pm
Forum: Ionic & Covalent Bonds
Topic: Polar Bonds
Replies: 19
Views: 107

### Re: Polar Bonds

Also, it is helpful to look at lone pairs. I remember there was a problem in the textbook in which we were asked to draw the figure of AsF3 and AsF5. And since the dipole moments cancelled out in AsF3, it was considered to have a lower boiling point because it was no longer polar. On the other hand,...
Fri Nov 20, 2020 1:36 pm
Forum: Sigma & Pi Bonds
Topic: Pi Bonds & Orbitals
Replies: 3
Views: 35

### Re: Pi Bonds & Orbitals

Sigma bonds show up only in s- orbitals and pi bonds show up in p- and d- orbitals, and so on. I'm not entirely sure if this is correct, but I distinctly remember reading this somewhere.
Sun Nov 15, 2020 12:08 am
Forum: Resonance Structures
Topic: lewis base or acid
Replies: 15
Views: 100

### Re: lewis base or acid

Lewis acids accept electrons, whereas Lewis bases donate electrons. It helps to draw out the Lewis structures to determine whether a molecule is a Lewis acid or base.
Fri Nov 13, 2020 11:22 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Exceptions?
Replies: 5
Views: 25

### Re: Electron Configuration Exceptions?

I believe the 4s subshell would be occupied first because it has a lower energy. But when it is written, you would write 3d before 4s. This link provides a nice visual for understanding which order subshells are filled: https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Map%3A_Organic_Chemist...
Fri Nov 13, 2020 11:18 pm
Forum: Electronegativity
Topic: Electronegativity Table/Chart in Lecture
Replies: 14
Views: 53

### Re: Electronegativity Table/Chart in Lecture

My TA said that we won't need to memorize the values. Rather, he suggested using and applying the trends in the periodic table to determine the difference in electronegativity.
Fri Nov 13, 2020 11:14 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 9
Views: 55

### Re: Polarizability

Polarizability refers to a measure of how easily an electron cloud is distorted by an electric field. And I believe polarizability and electronegativity are inversely related.
Fri Nov 13, 2020 11:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Textbook Question 2A3
Replies: 2
Views: 39

### Re: Textbook Question 2A3

For elements in the transition metals group, the elements occupy the d-block, which is why 3d^10 came before 4s^2. For example, for elements in period 4 would typically have this electron configuration: [Ar] 3d^10 4s^2. It helps to visualize it on a periodic table. Here's a link to check out: https:...
Sun Nov 08, 2020 1:44 pm
Forum: Octet Exceptions
Topic: Octet rule
Replies: 9
Views: 64

### Re: Octet rule

In simple terms, the octet rules refers to the tendency of atoms to prefer to have a full valence shell (8 electrons). Thus, atoms tend to form compounds in a way that allows them to have a complete valence shell. This website explains it very well: https://courses.lumenlearning.com/cheminter/chapte...
Fri Nov 06, 2020 11:05 pm
Forum: Student Social/Study Group
Topic: Studying From Home
Replies: 91
Views: 462

### Re: Studying From Home

It helps to change locations while studying at home! Sometimes I'd find myself unable to focus in my bedroom, but I've found that it helps to go to a different area in my house to study. Also, I recently read an article that said studying in various locations helps you retain the information you're ...
Thu Nov 05, 2020 12:38 pm
Forum: Lewis Structures
Topic: NO3-
Replies: 4
Views: 47

### Re: NO3-

I think Nitrogen, in this case, would be an exception because while drawing Lewis structures, symmetry also plays a role in determining the shape.
Tue Nov 03, 2020 6:18 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge and Lewis Structures
Replies: 10
Views: 71

### Re: Formal Charge and Lewis Structures

Formal charge would typically be used for determining the correct structure for the molecule. Thus, I believe you would most likely calculate formal charge when drawing structures that have resonance.
Tue Nov 03, 2020 6:10 pm
Forum: Trends in The Periodic Table
Topic: Inert-pair effect
Replies: 4
Views: 43

### Re: Inert-pair effect

In simple terms, the inert-pair effect is refers to the tendency of valence electrons to remain unshared in the compounds of post-transition metals. Here is a website that explains it well: https://courses.lumenlearning.com/chemistryformajors/chapter/periodicity-2/#:~:text=This%20phenomenon%2C%20the...
Sat Oct 31, 2020 8:47 pm
Forum: Trends in The Periodic Table
Topic: Periodic Table & Electron Affinity
Replies: 11
Views: 66

### Re: Periodic Table & Electron Affinity

Simply put, electron affinity increases as you move up a group and across a period. So, for example, Oxygen would have a higher electron affinity than Nitrogen and Sulfur.
Wed Oct 28, 2020 2:24 pm
Forum: Empirical & Molecular Formulas
Topic: Textbook Problem M.19
Replies: 8
Views: 82

### Re: Textbook Problem M.19

So firstly, what I would do is I would convert the masses of carbon dioxide, water, and nitrogen to the moles of Carbon in carbon dioxide, Hydrogen in water, and simply Nitrogen. To do this for carbon dioxide, you would essentially perform this calculation: 0.682gCO2 x (1molCO2/44.009gCO2) x (1molC/...
Wed Oct 28, 2020 2:14 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula - Whole Number Ratio
Replies: 9
Views: 85

### Re: Empirical Formula - Whole Number Ratio

There isn't really a set-in-stone cut off value for rounding moles to a whole number. But, in some of the UA sessions I've attended, they said to just use your logic in rounding and typically round down or up is the value is less than 0.1 or greater than 0.9. Hope this helps!
Wed Oct 28, 2020 2:13 pm
Forum: Administrative Questions and Class Announcements
Replies: 4
Views: 50

The UAs don't typically send out an answer key, in hopes of encouraging students to attend the Workshop/Step-Up/Drop-In sessions. I am sure you could post any lingering questions you may have about certain problems to Chemistry Community, and the students (including myself) would be more than happy ...
Tue Oct 27, 2020 8:57 pm
Forum: Photoelectric Effect
Topic: vacuum
Replies: 3
Views: 45

### Re: vacuum

The photoelectric effect needs to be done under a vacuum so that the experimental conditions are as controlled as possible. If the photoelectric effect weren't done under a vacuum, then the electrons would interact with the atoms in the atmosphere, which would have an influence on the experimental r...
Sat Oct 24, 2020 10:43 am
Forum: Molarity, Solutions, Dilutions
Topic: molar mass and g/mol
Replies: 2
Views: 43

### Re: molar mass and g/mol

Yes, typically when writing the molar mass, it is always assumed that its units are g/mol.
Wed Oct 21, 2020 3:55 pm
Forum: Student Social/Study Group
Replies: 7
Views: 78

I've been going to a few each week, and I find them super helpful! The UA workshops and step-up sessions are where UAs would give you a worksheet to work on, and it really great extra practice. I haven't gone to any drop-in sessions, but I hear that those are most like office hours, and you can go t...
Wed Oct 21, 2020 3:43 pm
Forum: *Shrodinger Equation
Topic: Midterm 1 [ENDORSED]
Replies: 3
Views: 101

### Re: Midterm 1[ENDORSED]

I think we will only have to be able to understand the relationship between Schrodinger's equation (H ψ = E ψ), wave functions, and orbitals. But not necessarily know how to apply them to particular questions. I think he just wants us to understand Schrodinger's equation from a fundamental and conce...
Wed Oct 21, 2020 3:39 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Midterm 1
Replies: 5
Views: 80

### Re: Midterm 1

We will not be tested on wave functions and atomic orbitals. In Dr. Lavelle's email, he stated that we wouldn't need to be responsible for the last 8 topics on the Outline 2: The Quantum World. Hope this clears up any confusion!
Mon Oct 19, 2020 3:18 pm
Forum: General Science Questions
Topic: Webcams
Replies: 17
Views: 119

### Re: Webcams

Hi! Here is a link to the webcam I purchased: https://www.amazon.com/gp/product/B088F ... UTF8&psc=1. I also have a MacBook Pro, and this camera works excellently.
Tue Oct 13, 2020 12:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Webcam
Replies: 5
Views: 117

### Webcam

Hi! So I just saw Dr. Lavelle's email regarding the Equipment Request form, and I noticed that a webcam was listed. Does this mean we need to purchase an additional webcam, even if our laptop already has a built-in one? Thanks!
Tue Oct 13, 2020 11:32 am
Forum: Properties of Light
Topic: Gamma Rays
Replies: 5
Views: 47

### Re: Gamma Rays

The order would be: Gamma Rays > X-rays > Ultraviolet Rays. On the electromagnetic spectrum, energy increases as frequency increases and wavelength decreases. Thus, the rays with the higher frequency and smaller wavelengths would generally be the strongest.
Tue Oct 13, 2020 11:30 am
Forum: SI Units, Unit Conversions
Topic: Nomenclature
Replies: 7
Views: 69

### Re: Nomenclature

If I remember correctly, I believe he said that on exams he would provide the name of the compounds with the molecular formula in parenthesis. I assume it would look similar to this: "carbon monoxide (CO)."
Tue Oct 13, 2020 11:24 am
Forum: Administrative Questions and Class Announcements
Topic: Quizzes in Discussion Sections?
Replies: 6
Views: 80

### Re: Quizzes in Discussion Sections?

The quizzes are just to test the lockdown browser for when we use Respondus for our midterms and final. On a separate note, does anyone know how we would be able to remain on Zoom during the duration of our exam if Respondus closes the Zoom application once we login?
Tue Oct 13, 2020 11:19 am
Forum: Properties of Electrons
Topic: keV
Replies: 4
Views: 26

### Re: keV

keV stands for 'kiloelectric volts.' This unit could be converted to Joules using this conversion factor: 1 eV = 1.602 × 10^-19 J.
Mon Oct 12, 2020 12:05 pm
Forum: Photoelectric Effect
Topic: Where does photon energy go if it does not emit an electron?
Replies: 6
Views: 69

### Re: Where does photon energy go if it does not emit an electron?

Hi! If there is not enough energy to emit an electron, then that energy will simply be absorbed by the metal.
Sun Oct 11, 2020 10:11 pm
Forum: Student Social/Study Group
Topic: High School Chemistry Review/Resources
Replies: 6
Views: 68

### Re: High School Chemistry Review/Resources

Hi! I agree with the post above, Khan Academy is a life saver! Also, if you look up "Chemistry Lumen Learning" on Google, it should take you to this website: https://courses.lumenlearning.com/introchem/. This is an excellent resource that explains topics in a a very understandable manner! ...
Mon Oct 05, 2020 2:42 pm
Forum: Administrative Questions and Class Announcements
Topic: UA Peer Learning Sessions
Replies: 7
Views: 94

### Re: UA Peer Learning Sessions

When expressing a number in scientific notation, the number being expressed should be between 1 and 10. For example, when expressing 10000.00 in scientific notation, I would express it as 1.00 * 10^4 rather than 100.00*10^2 because in the first one 1.00 is between 1 and 10. At least this is how I le...
Mon Oct 05, 2020 12:41 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question about Moles of Solute
Replies: 10
Views: 82

### Re: Question about Moles of Solute

Here's how I like to think of it (and this is a great example provided by Dr. Lavelle in today's lecture): Imagine you have a vitamin C (C6H8O6) tablet. When you add water to that tablet and that tablet dissolves, have the moles in that tablet changed? The answer to that would be no. Thus, in these ...
Mon Oct 05, 2020 11:00 am
Forum: Molarity, Solutions, Dilutions
Topic: Balancing Chemical Equations
Replies: 12
Views: 151

### Re: Balancing Chemical Equations

When balancing a chemical equation, you would typically want it in its simplest form for nicer numbers when doing calculations related to that chemical equation. I think there are definitely instances in which you balance a chemical equation and realize that it is not in its simplest form. In that c...
Mon Oct 05, 2020 10:53 am
Forum: Administrative Questions and Class Announcements
Topic: UA Peer Learning Sessions
Replies: 7
Views: 94

### Re: UA Peer Learning Sessions

I'm not entirely sure if each UA session goes over the same exact material, but I'd assume that they review the material that we are learning in lectures for that week. You don't need to attend every single UA session. I would recommend going to the sessions, as necessary. So if you feel that you ne...
Mon Oct 05, 2020 9:08 am
Forum: Student Social/Study Group
Replies: 13
Views: 145

### Re: E-book and Sampling Link

Hi! An email was sent out to a student in this course who had the same issue. Turns out, if you bought your code from the UCLA store, there's a chance you may not get it for a few more weeks. The reason being that the UCLA store has run out of Access Codes and they are still waiting for more from th...
Mon Oct 05, 2020 8:57 am
Forum: SI Units, Unit Conversions
Topic: Fundamentals F.23 [ENDORSED]
Replies: 7
Views: 163

### Re: Fundamentals F.23[ENDORSED]

So for this one, you are going to determine what percentage of C (Carbon) is present in each of these compounds. So, for example, in part (a) you will be determining what percentage of C (Carbon) is in ethene, whose molecular formula is C2H4. To do this, you will first find the molar mass of ethene....
Sun Oct 04, 2020 5:35 pm
Forum: Student Social/Study Group
Topic: Sapling Learning Problem
Replies: 3
Views: 107

### Re: Sapling Learning Problem

I had a similar issue, and I was able to resolve it by accessing Sapling Learning through Dr. Lavelle's page on CCLE. Just click on Dr. Lavelle's site and at the very bottom of the 'Site Info' tab there is a hyperlink that says "Chemistry Principles/Sapling Learning." Just click on that an...
Sat Oct 03, 2020 8:44 pm
Forum: Empirical & Molecular Formulas
Topic: Mass Percent for Empirical and Molecular Formulas [ENDORSED]
Replies: 9
Views: 302

### Re: Mass Percent for Empirical and Molecular Formulas[ENDORSED]

The mass percent is essential for finding empirical and molecular formulas because it tells you the amount of each element that is present in any given compound. Then by treating each mass percent as a portion of the compound with a sample of 100g, you can more easily find the amount of moles in eac...
Thu Oct 01, 2020 4:50 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions [ENDORSED]
Replies: 6
Views: 325

### Re: Balancing Chemical Reactions[ENDORSED]

This is how I went about this question: Skeletal Second Stage Chemical Equation - Fe3O4 + CO --> Fe + CO2 So for balancing the chemical equation for the second stage, I'd start by first balancing Fe. Thus, I'm left with this chemical equation: Fe3O4 + CO--> 3Fe + CO2. Next, I'd experiment to see how...