Search found 38 matches

by Diana Chavez-Carrillo 3J
Tue Nov 12, 2019 9:08 pm
Forum: Bond Lengths & Energies
Topic: Homework for week 7
Replies: 2
Views: 11

Re: Homework for week 7

Yes, my TA said we can do HW problems from chemical bonds and/or molecular shape and structure since we did not cover all of the chemical bonds and Lavelle finished covering it after the midterm. But I would suggest you try to do more HW problems on the section with molecular shape and structure sin...
by Diana Chavez-Carrillo 3J
Mon Nov 04, 2019 2:53 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarity vs Polarizability
Replies: 3
Views: 37

Re: Polarity vs Polarizability

Polarizability is the ability of an atom to form temporary dipoles. In other words, it is the ability to be polarized by another. Polarizing power is the ability to polarize another. Typically a bigger atomic radius means higher polarizability because a bigger electron cloud is more easily distorted...
by Diana Chavez-Carrillo 3J
Mon Nov 04, 2019 2:13 pm
Forum: Resonance Structures
Topic: Octet
Replies: 13
Views: 62

Re: Octet

So far what I have gathered from TAs and Lavelle's lectures, the exceptions include the following: Incomplete octets (meaning it can have less than 8 electrons) are the first 4 elements on the periodic table: H, He, Li, Be, AND B, Al. Expanded octets (meaning it can have more than 8 electrons) are e...
by Diana Chavez-Carrillo 3J
Mon Nov 04, 2019 2:00 pm
Forum: Trends in The Periodic Table
Topic: ionization energy vs electronegativity
Replies: 4
Views: 14

Re: ionization energy vs electronegativity

Just keep in mind that the ionzation energy trend is not exactly the same as the electronegativity trend because for ionization energy there is an exception when it comes to Nitrogen and Oxygen. For the most part, ionization energy does increase going up and across to the right of the periodic table...
by Diana Chavez-Carrillo 3J
Mon Nov 04, 2019 1:52 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy from the Review
Replies: 4
Views: 21

Re: Ionization Energy from the Review

So then when it comes to ionization energy is the only exemptions nitrogen and oxygen? Are the rest of the elements still increasing in ionization energy going up and across to the right of the periodic table which is the same trend as electronegativity on the periodic table?
by Diana Chavez-Carrillo 3J
Mon Nov 04, 2019 1:32 pm
Forum: General Science Questions
Topic: Midterm
Replies: 12
Views: 112

Re: Midterm

Does anyone know if we can use whiteout during the midterm exam? I know we are supposed to write in pen so I was wondering if we could use whiteout since we do have a limited amount of space to do calculations.
by Diana Chavez-Carrillo 3J
Wed Oct 30, 2019 11:29 pm
Forum: Electronegativity
Topic: Electronegativity trends
Replies: 5
Views: 17

Re: Electronegativity trends

Yes, electronegativity counts as a trend on the periodic table. It is important for things like determining if elements have an ionic bond or a covalent bond. Electronegativity, electron affinity, and ionization energy have the same trend (increase up the table and to the right across the periodic t...
by Diana Chavez-Carrillo 3J
Wed Oct 30, 2019 10:43 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 28
Views: 143

Re: Midterm

Since we need to know the electronegativity differences to determine if there are ionic bonds or covalent bonds, will we be given on the midterm an electronegativity chart that shows each element's electronegativity or do we need to memorize them?
by Diana Chavez-Carrillo 3J
Wed Oct 30, 2019 10:36 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 1710

Re: Test 1 [ENDORSED]

Will we be given some sort of answer key or rationale for the correct answers in Test 1 in order to review our mistakes and thus study for the midterm that will include questions similar to Test 1?
by Diana Chavez-Carrillo 3J
Wed Oct 30, 2019 10:00 pm
Forum: Ionic & Covalent Bonds
Topic: ionic vs covalent bonds
Replies: 6
Views: 30

Re: ionic vs covalent bonds

In today's lecture (10/30/19) Lavelle mentioned how Cl has a (-) charge while K is (+) charge. I know its probably really simple but could someone please clarify/remind me how do we determine if an element is +1 or -1. For example, how is Cl becoming into Cl-1 and K becoming K+.
by Diana Chavez-Carrillo 3J
Wed Oct 30, 2019 9:53 pm
Forum: Ionic & Covalent Bonds
Topic: Format of midterm?
Replies: 12
Views: 56

Re: Format of midterm?

Would we still be given partial credit for questions on the midterm like Test 1 or no?
by Diana Chavez-Carrillo 3J
Thu Oct 24, 2019 1:16 pm
Forum: Trends in The Periodic Table
Topic: Summary of Periodic Trends
Replies: 7
Views: 64

Re: Summary of Periodic Trends

Is electron affinity only important/ only affects Group 17 (according to Lavelle) and noble gases? Or why is it important to know the electron affinity?
by Diana Chavez-Carrillo 3J
Thu Oct 24, 2019 12:23 pm
Forum: Trends in The Periodic Table
Topic: Trends
Replies: 5
Views: 33

Re: Trends

I think some of the main trends you should keep in mind are: Electron affinity: Lavelle mentioned that this is less periodic but generally there is HIGH electron affinity for elements in the TOP RIGHT of the periodic table (Group 17). Atomic radius : increases DOWN the periodic table increases FROM ...
by Diana Chavez-Carrillo 3J
Thu Oct 24, 2019 11:54 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: coulomb potential energy
Replies: 4
Views: 28

Re: coulomb potential energy

What does the infinity-like symbol next to the equation (q1)(q2)/r mean?
Also, would we need this equation to do calculations or is it just the concept about like attraction and potential energy that we need to understand?
by Diana Chavez-Carrillo 3J
Thu Oct 24, 2019 11:17 am
Forum: Administrative Questions and Class Announcements
Topic: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
Replies: 44
Views: 1133

Re: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE

Does anyone know if any other UAs post their worksheets on Chemistry Community?? These worksheets are so helpful especially for me whose high school chemistry background is essentially nonexistent. Thank you so much Karen for posting these! Yeah, I found another UA who posts helpful worksheets too ...
by Diana Chavez-Carrillo 3J
Wed Oct 23, 2019 2:54 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations for electrons in the D subshell
Replies: 5
Views: 33

Re: Electron Configurations for electrons in the D subshell

Could someone explain to me why is it that when you start to include the d into our electron configuration the order is that d goes first then s. In highschool I was taught to just follow the order where it is s then p for the first 3 rows but then for the 4th row it would be s, d, p but I see that ...
by Diana Chavez-Carrillo 3J
Thu Oct 17, 2019 8:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: quantum number topic
Replies: 4
Views: 19

Re: quantum number topic

n is the principal quantum number that shows the number of shells and indicates the size and energy. l is the angular momentum quantum number that indicates the shape. ml shows the orbitals. ml is not the same number as l because l is the subshells that consist of 0 (s orbital),1 (p orbital),2 (d or...
by Diana Chavez-Carrillo 3J
Thu Oct 17, 2019 1:18 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.25
Replies: 2
Views: 14

Re: 1D.25

A subshell notation is basically whether it will be s, p, d, etc. So if n=2 and l=1 then the subshell will be 2p because l=0 is "s," l=1 is "p", l=2 would have been "d", etc.
by Diana Chavez-Carrillo 3J
Thu Oct 17, 2019 12:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quantum Numbers
Replies: 7
Views: 62

Re: Quantum Numbers

I am still confused about how to calculate the magnetic quantum number (ml) based on the principal quantum number (n) and angular momentum number( l ). Could someone please explain to me the process of finding it? Like I know that (l) is dependent on (n) but the (ml) still confuses me. m l is the m...
by Diana Chavez-Carrillo 3J
Wed Oct 16, 2019 2:35 pm
Forum: Properties of Light
Topic: Midterm- Electromagnetic spectrum
Replies: 3
Views: 29

Re: Midterm- Electromagnetic spectrum

I think it would be important if you at least get a general idea of where each electromagnetic radiation is like gamma rays being in the left side (before visible light) with the highest Energy and radios being in the right side (after the visible light spectrum which is usually in the middle) where...
by Diana Chavez-Carrillo 3J
Wed Oct 16, 2019 2:14 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quantum Numbers
Replies: 7
Views: 62

Re: Quantum Numbers

I am still confused about how to calculate the magnetic quantum number (ml) based on the principal quantum number (n) and angular momentum number( l ). Could someone please explain to me the process of finding it? Like I know that (l) is dependent on (n) but the (ml) still confuses me. For example, ...
by Diana Chavez-Carrillo 3J
Wed Oct 16, 2019 1:44 pm
Forum: Properties of Light
Topic: Constant for Speed of Light
Replies: 14
Views: 63

Constant for Speed of Light

I am wondering what constant would Lavelle prefer/require us to use throughout our homework problems and next exam when it comes to speed of light because the Solution Manual used 2.998*10^8 m*s^-1 but in my PLF we used 3.0*10^8 m*s^-1. I am aware that each one can you give you a different answer so...
by Diana Chavez-Carrillo 3J
Wed Oct 09, 2019 2:35 pm
Forum: Empirical & Molecular Formulas
Topic: Molecular formula
Replies: 6
Views: 75

Re: Molecular formula

Everyone above is correct but I personally like to see actual examples to better understand a concept so I provided you with a step-by-step example I solved from a cool website that provides practice problems like this https://chem.libretexts.org : Determine the empirical and molecular formula for c...
by Diana Chavez-Carrillo 3J
Wed Oct 09, 2019 2:22 pm
Forum: Significant Figures
Topic: Are we allowed to round when showing work?
Replies: 7
Views: 39

Re: Are we allowed to round when showing work?

I would personally say to write out your calculations exactly as you input them on your calculator ( unrounded) because if you do by any chance make a mistake with your sig figs in your final answer then your TA will look at your work (for partial credit) and by providing the unrounded values they w...
by Diana Chavez-Carrillo 3J
Wed Oct 09, 2019 1:58 pm
Forum: SI Units, Unit Conversions
Topic: Homework Grading Clarification [ENDORSED]
Replies: 8
Views: 298

Re: Homework Grading Clarification [ENDORSED]

So say we complete every part of the question correctly, but right at the end we mess up on our sig figs, we'll still get no credit for any of our previous work? In my discussion, one of the students asked this to our TA and he said that you will be able to get partial credit if you show your work ...
by Diana Chavez-Carrillo 3J
Wed Oct 09, 2019 1:38 pm
Forum: Significant Figures
Topic: Question About Significant Figures and Rounding
Replies: 22
Views: 193

Re: Question About Significant Figures and Rounding

When we add molar masses of elements to get the total matter weight of compounds, should I use the entire number that the periodic table gives? or should I round certain numbers? I noticed that the periodic table Lavelle has shown us compared to one I had back home has different amount of numbers a...
by Diana Chavez-Carrillo 3J
Wed Oct 09, 2019 1:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 962

Re: Week 2 Homework Problems [ENDORSED]

Are the TA's grading our homework based on completion or correctness?
by Diana Chavez-Carrillo 3J
Wed Oct 02, 2019 7:29 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: How to access e textbook
Replies: 4
Views: 47

Re: How to access e textbook

The sapling came in my bundle but to be completely honest I am not sure what is it used for like is it to just access an online version of the textbook or is there other important information we can only access through the sapling code/booklet that came with the bundle?
by Diana Chavez-Carrillo 3J
Wed Oct 02, 2019 7:16 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Solubility Rules Memorization ?
Replies: 3
Views: 37

Re: Solubility Rules Memorization ?

To build off of that question, if the question shows the solubility like (l) or (s) or (aq) would it matter if throughout our problem solving and the final answer it does not have the solubility or do we have to include it throughout and the final answer?
by Diana Chavez-Carrillo 3J
Wed Oct 02, 2019 7:06 pm
Forum: Empirical & Molecular Formulas
Topic: Homework question M.17
Replies: 2
Views: 26

Homework question M.17

In my discussion, we were working on problem M.17 but did not get to finish it and I got stuck near the end of solving the problem so I went to the Solution Manual and for "finding the molar mass of XA" it set it up as (231-1.0) + (125-17) to equal 338 g/mol. However, I do not understand w...
by Diana Chavez-Carrillo 3J
Tue Oct 01, 2019 11:43 pm
Forum: Significant Figures
Topic: Question About Significant Figures and Rounding
Replies: 22
Views: 193

Re: Question About Significant Figures and Rounding

As a visual learner, I found the following images attached below that have helped me better understand the rules with sig figs. Hopefully, it can help some of you too. In sum, nonzero digits always count as a sig fig. For zero digits, if its inbetween nonzero digits it counts and if the zeros are af...
by Diana Chavez-Carrillo 3J
Tue Oct 01, 2019 10:59 pm
Forum: Empirical & Molecular Formulas
Topic: Mass % Composition
Replies: 7
Views: 62

Re: Mass % Composition

I am still a bit confused about when to divide the mass percentage by 100g and when to just take the percentage and make it into grams. For example, in the homework problem E.11, we took the percentages like 7.42% from one of the isotopes and divided by 100 to get 0.0742. However, when looking at th...
by Diana Chavez-Carrillo 3J
Thu Oct 11, 2018 5:52 pm
Forum: General Science Questions
Topic: Periodic Table
Replies: 16
Views: 512

Re: Periodic Table

It is best and safer to just keep the number exactly as seen on the periodic table so that you do not round too much. Usually you do the rounding until the very end of your calculations.
by Diana Chavez-Carrillo 3J
Thu Oct 11, 2018 4:57 pm
Forum: Significant Figures
Topic: Rounding Using Significant Figures
Replies: 10
Views: 534

Re: Rounding Using Significant Figures

What is the rule with the zeros when counting sig figs because I know that there are times you do not count the zero as a sig fig but sometimes you do. When do you know to count the zero as a sig fig?
by Diana Chavez-Carrillo 3J
Thu Oct 11, 2018 4:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Number of questions on test one [ENDORSED]
Replies: 39
Views: 17735

Re: Number of questions on test one [ENDORSED]

If we do not understand what a question on the test asks is it allowed to ask for clarity from our TA's?
by Diana Chavez-Carrillo 3J
Wed Oct 03, 2018 8:36 pm
Forum: SI Units, Unit Conversions
Topic: Homework Grading Clarification [ENDORSED]
Replies: 8
Views: 298

Re: Homework Grading Clarification [ENDORSED]

Is it possible to get partial credit for homework problems?
by Diana Chavez-Carrillo 3J
Wed Oct 03, 2018 8:31 pm
Forum: SI Units, Unit Conversions
Topic: Textbook Homework Assignment
Replies: 11
Views: 534

Re: Textbook Homework Assignment

Is it possible to get credit if you do all the problems rather than just 7 problems?
by Diana Chavez-Carrillo 3J
Wed Oct 03, 2018 7:45 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 9
Views: 876

Re: Sig Figs

How can you check if your sig. figs. are too precise or not rounded off enough?

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