Search found 52 matches

by Alan Cornejo 1a
Mon Feb 10, 2020 11:23 pm
Forum: Phase Changes & Related Calculations
Topic: Molar Internal Energy
Replies: 2
Views: 19

Re: Molar Internal Energy

Thank you
by Alan Cornejo 1a
Mon Feb 10, 2020 8:00 pm
Forum: Phase Changes & Related Calculations
Topic: Reversible or Irreversible
Replies: 5
Views: 17

Re: Reversible or Irreversible

Yes we would assume it is reversible as most chemical reactions are reversible, usually from the context you can infer from the question such as it stating that the pressure is constant or not constant,
by Alan Cornejo 1a
Mon Feb 10, 2020 7:49 pm
Forum: Phase Changes & Related Calculations
Topic: Molar Internal Energy
Replies: 2
Views: 19

Molar Internal Energy

Does anybody know if the midterm will be covering molar internal energy with the likeliness of translational and rotational energy ?
by Alan Cornejo 1a
Sun Dec 08, 2019 11:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Representing larger molecules
Replies: 4
Views: 43

Re: Representing larger molecules

The atom thats least electronegative should be the central atom, if you have two I would assume it would be best to create the shape by simply drawing the structure according to the appearance in the chemical formula.
by Alan Cornejo 1a
Sun Dec 08, 2019 11:44 pm
Forum: Hybridization
Topic: Charges
Replies: 4
Views: 51

Re: Charges

If the molecule or atom has a negative or positive charge it is best to portray so, if it is neutral there is really no need.
by Alan Cornejo 1a
Sun Dec 08, 2019 11:42 pm
Forum: Naming
Topic: ion at end of name
Replies: 4
Views: 44

Re: ion at end of name

405268063 wrote:Yup, if there are no cations or anions attached to it, you also add "ion" at the end of the name.


THis is correct, if not cations or anions seem to from with it, the ion name will be added
by Alan Cornejo 1a
Sun Dec 08, 2019 11:39 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 2
Views: 31

Re: Lewis Structures

the least electronegative atom is typically the central molecule. hydrogens will always be on the outside since they can only form one bond. make sure to know specific trends (such as how carbon always wants to make 4 bonds to keep the FC at 0) This is correct, usually the atom thats least electron...
by Alan Cornejo 1a
Sun Dec 08, 2019 11:37 pm
Forum: Lewis Structures
Topic: Cl as a central atom
Replies: 3
Views: 51

Re: Cl as a central atom

Chlorine is one of the few atoms of which can also break the octet rule allowing it to expand its shells and hold more than 8 electrons
by Alan Cornejo 1a
Sun Dec 08, 2019 11:35 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Vs Pi
Replies: 10
Views: 64

Re: Sigma Vs Pi

Pi bonds occur with double bonded or triple bonded atoms, while sigma bonds occur with single bonds. Sigma bonds are going to be weaker and longer bonds than a pi bond.
by Alan Cornejo 1a
Sun Dec 08, 2019 11:09 pm
Forum: Properties of Light
Topic: speed of light and protons
Replies: 3
Views: 51

Re: speed of light and protons

For the simple fact that protons of mass, they cannot reach the speed of light, objects with mass cannot travel at the speed of light
by Alan Cornejo 1a
Sun Dec 08, 2019 11:05 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7826
Views: 1086448

Re: Post All Chemistry Jokes Here

Helium walks into a bar,
The bar tender says "We don't serve noble gasses in here."
Helium doesn't react.
by Alan Cornejo 1a
Sun Dec 08, 2019 11:02 pm
Forum: General Science Questions
Topic: Curve
Replies: 9
Views: 128

Re: Curve

In order to pass the class you need at least 250/500 points to pass with a C-. The rest of the grades as far as A's and B's I believe will be graded on a curve dependent on the overall/average score of students.
by Alan Cornejo 1a
Sun Dec 08, 2019 10:58 pm
Forum: Student Social/Study Group
Topic: Final Jitters
Replies: 97
Views: 20182

Re: Final Jitters

Being able to be in a relaxed state of mind is the best thing you can do for your self, this can be done through reviewing days ahead in advance to avoid cramming and using the last day to do an easy guide over and to relax and have fun, as having fun and laughing is proven to enhance neural pathway...
by Alan Cornejo 1a
Sat Dec 07, 2019 10:08 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 1684

Re: Rydberg equation [ENDORSED]

Can someone help me understand why we use the Rydberg equation? The Rydberg equation is used to calculate the energy of an electron at a certain principle quantum level of an atom. We'll usually use it in problems where we're asked to calculate the change in energy, frequency, or velocity that occu...
by Alan Cornejo 1a
Sat Dec 07, 2019 10:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarizability
Replies: 4
Views: 39

Re: polarizability

London dispersion forces are weaker than the other intermolecular forces and therefore does not exert high polarizability
by Alan Cornejo 1a
Sat Dec 07, 2019 9:55 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelates
Replies: 5
Views: 68

Re: Chelates

You would look for ligands that act as polydentate. For example, if the coordination compound has ethylenediamine or en, you would know that it is chelating since en is a bidentate. This is correct, as long as you identify the ligands that have two or more atoms capable of binding to a central meta...
by Alan Cornejo 1a
Sat Dec 07, 2019 9:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand polydentate
Replies: 4
Views: 47

Re: Ligand polydentate

I'm not entirely sure, but I think it depends on the lone pairs within a molecule. Like water is a monodentate because it can only bond through oxygen which has 2 sets of lone pairs. With en (ethylenediamine) since it has multiple nitrogens with lone pairs, it is able to bond through multiple site,...
by Alan Cornejo 1a
Sat Dec 07, 2019 9:47 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelating ligands [ENDORSED]
Replies: 21
Views: 1892

Re: chelating ligands [ENDORSED]

Angela Prince 3B wrote:
Elizabeth Harty 3A wrote:How do you know if there are sigma bonds available for rotation?


all sigma bonds can rotate, but pi bonds cannot


Thank you for the clarification .
by Alan Cornejo 1a
Sat Dec 07, 2019 9:45 pm
Forum: Lewis Structures
Topic: Expanded Octets
Replies: 2
Views: 25

Expanded Octets

I know that atoms in group 3 can break the octet rule, but I have also seen similarly that even atoms like Cl can break the octet rule, Is there any other atoms outside of group 3, that can also break the octet rule, and if so is there a certain way to identify why exactly they are able to break the...
by Alan Cornejo 1a
Sat Dec 07, 2019 9:41 pm
Forum: Lewis Structures
Topic: Bent or Angular?
Replies: 15
Views: 95

Re: Bent or Angular?

Jamie Lee 1D wrote:Technically they are the same thing so I don't think it matters, you would most likely get a problem correct with either name. Lavelle used bent in his lecture though.


Both terms usually refer to the same thing, correct.
by Alan Cornejo 1a
Sat Dec 07, 2019 9:39 pm
Forum: Lewis Structures
Topic: Lewis for carbon monoxide
Replies: 3
Views: 25

Re: Lewis for carbon monoxide

Carbon Monoxide has a total of 10 valence electrons. Carbon having four and Oxygen having six they combine to have 10 total valence electrons. If the carbon and oxygen were double bonded (4 shared electrons), and each had a single pair then you would only have a total of 8 valence electrons. 1 lone ...
by Alan Cornejo 1a
Sat Dec 07, 2019 9:32 pm
Forum: Octet Exceptions
Topic: Octet exception
Replies: 13
Views: 104

Re: Octet exception

Elements in the 3p or higher orbital are exceptions to the octet rule. This is because they have an empty d-orbital that allows them to hold more than 8 valence e-, e.g. for P, it is located in the 3p orbital, but has an empty 3d orbital that allows it to hold more than 8 e- and be an exception. Th...
by Alan Cornejo 1a
Sat Dec 07, 2019 9:29 pm
Forum: Sigma & Pi Bonds
Topic: Sigma vs. Pi
Replies: 15
Views: 108

Re: Sigma vs. Pi

zachary_nhem_4I wrote:Sigma bonds are stronger because the two orbitals overlap, as opposed to a pi bond where the two orbitals are side by side.


This response is correct as the overlapping of two P orbitals causes the stronger force.
by Alan Cornejo 1a
Sat Dec 07, 2019 9:26 pm
Forum: Sigma & Pi Bonds
Topic: pi bonds
Replies: 5
Views: 47

Re: pi bonds

Yes any single bond has one sigma bond, a double bond has one sigma and two pi bonds, and a triple bond has 1 pi and two sigma bonds
by Alan Cornejo 1a
Wed Dec 04, 2019 6:26 pm
Forum: Sigma & Pi Bonds
Topic: sigma and pi bonds
Replies: 19
Views: 110

Re: sigma and pi bonds

Yes all single bonds are sigma bonds, and double bonds contain one sigma and one pi bond, and a triple bond contains 2 pi bonds and one sigma.
by Alan Cornejo 1a
Wed Dec 04, 2019 6:24 pm
Forum: Administrative Questions and Class Announcements
Topic: How to list Chem_Mod posts
Replies: 12
Views: 32640

Re: How to list Chem_Mod posts

Thanks for the help !
by Alan Cornejo 1a
Wed Dec 04, 2019 6:23 pm
Forum: Student Social/Study Group
Topic: Finals Preparation
Replies: 7
Views: 53

Re: Finals Preparation

I think that a good night's sleep is pretty important too. I'd suggest to not stay up super late cramming because that can limit your ability to perform on the test due to lack of sleep. Yeah I've read about how sleep can inhibit cognitive abilities by over 60% over just one bad nights sleep. Thanks
by Alan Cornejo 1a
Wed Dec 04, 2019 6:21 pm
Forum: Student Social/Study Group
Topic: Week 10 Chemistry Community
Replies: 9
Views: 108

Re: Week 10 Chemistry Community

Sunday is the deadline and we must have 50 posts
by Alan Cornejo 1a
Wed Dec 04, 2019 6:19 pm
Forum: Student Social/Study Group
Topic: Practice Final
Replies: 17
Views: 237

Re: Practice Final

If you search for "marshmallow" you will find past exam problems for review
by Alan Cornejo 1a
Wed Dec 04, 2019 6:18 pm
Forum: Student Social/Study Group
Topic: Grades
Replies: 14
Views: 154

Re: Grades

On the syllabus it says a 50% is needed to pass with a C- or higher and so I assume thats a curve in and of itself
by Alan Cornejo 1a
Wed Dec 04, 2019 6:16 pm
Forum: Student Social/Study Group
Topic: Preparing for the final
Replies: 25
Views: 161

Re: Preparing for the final

I really feel like going to the review sessions helps alot as it helped me greatly and they are very useful
by Alan Cornejo 1a
Wed Dec 04, 2019 6:13 pm
Forum: Student Social/Study Group
Topic: Finals Preparation
Replies: 7
Views: 53

Re: Finals Preperation

ramiro_romero wrote:Just make sure you eat an apple, glucose molecules will store in your body and fuel your brain ability!

Thats a great idea, thanks for the advice.
by Alan Cornejo 1a
Wed Dec 04, 2019 6:10 pm
Forum: Student Social/Study Group
Topic: Finals Preparation
Replies: 7
Views: 53

Finals Preparation

Any thoughts/advice as to the best nutritious and energizing breakfasts for sunday morning before the final ?
by Alan Cornejo 1a
Sun Oct 27, 2019 8:13 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7826
Views: 1086448

Re: Post All Chemistry Jokes Here

A conversation between two atoms:
I think I’ve lost an electron.
Are you sure?
Yeah, I’m positive.
by Alan Cornejo 1a
Sun Oct 27, 2019 8:12 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7826
Views: 1086448

Re: Post All Chemistry Jokes Here

My teacher threw Sodium Chloride at me. That’s a salt.
by Alan Cornejo 1a
Sun Oct 27, 2019 8:11 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7826
Views: 1086448

Re: Post All Chemistry Jokes Here

“What do you do with a sick chemist?”
“If you can’t helium, and you can’t curium, then you might as well barium.”
by Alan Cornejo 1a
Sun Oct 27, 2019 8:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7826
Views: 1086448

Re: Post All Chemistry Jokes Here

helium walks into a bar and orders a beer. The bartender says, “Sorry, we don’t serve noble gases here.” He doesn’t react
by Alan Cornejo 1a
Sun Oct 20, 2019 11:12 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Advice for studying
Replies: 58
Views: 544

Re: Advice for studying

Alexis 3F wrote:I've been attending the workshops a few times a week and it's made suchhhh a positive improvement!!!!


I also found this to be super helpful
by Alan Cornejo 1a
Sun Oct 20, 2019 11:10 pm
Forum: Properties of Electrons
Topic: Angstrom Conversion
Replies: 12
Views: 103

Re: Angstrom Conversion

905416023 wrote:It is 1 angstrom to 10^-10 m


correct answer
by Alan Cornejo 1a
Sun Oct 20, 2019 11:04 pm
Forum: Properties of Light
Topic: What are the units of hertz
Replies: 41
Views: 239

Re: What are the units of hertz

nicolely3B wrote:Hz is the unit for 1 cycle/second. The cycle refers to a wave's cycle and it's from the peak of one wave to the trough of the next



perfect explanation
by Alan Cornejo 1a
Sun Oct 20, 2019 10:59 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 132
Views: 77562

Re: Reading the textbook [ENDORSED]

reading the textbook is an obvious super helpful tool, to better go in depth as to what you are learning and practice.
by Alan Cornejo 1a
Sun Oct 20, 2019 10:57 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent
Replies: 29
Views: 520

Re: Ionic vs Covalent

Typically, ionic bonds are stronger but there are exceptions such as weakened ionic bonds as water as well as special strengthened covalent bonds known as covalent network bonding.
by Alan Cornejo 1a
Sun Oct 13, 2019 10:04 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 132
Views: 77562

Re: Reading the textbook [ENDORSED]

I used these for my AP Chemistry class in high school, but I think they have some college-level chem as well: https://chem.libretexts.org/ https://www.youtube.com/channel/UCEWpbFLzoYGPfuWUMFPSaoA https://www.youtube.com/watch?v=IFKnq9QM6_A&list=PLJfwA7_CzYE_qLSXH2hJkpffcrc76NjHJ Hope this helps...
by Alan Cornejo 1a
Sun Oct 13, 2019 10:02 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Wavelength Plausibility
Replies: 30
Views: 858

Re: Wavelength Plausibility

madeleine_dis1E wrote:Yes, the 700-400nm example he gave is meant to provide a mental picture of the range however the actual scale is from 720-400. Either way you want to remember it is ok.


correct, 700 is just used for an easier conceptualization of the actual range
by Alan Cornejo 1a
Sun Oct 13, 2019 9:54 pm
Forum: Administrative Questions and Class Announcements
Topic: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
Replies: 53
Views: 2484

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

great tool and resource to help review and further cement the fundamentals of each topic covered in class !
by Alan Cornejo 1a
Sun Oct 13, 2019 9:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 1692

Re: Week 2 Homework Problems [ENDORSED]

You have the option of either doing more problems from week 1 of Chem review or the quantam world
by Alan Cornejo 1a
Sun Oct 13, 2019 9:38 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 2840

Re: Test 1 [ENDORSED]

I don't know if someone has asked this already but would we get partial credit for unfinished problems headed in the right direction? I was also wondering this as, I was also curious as to how far off of an answer would grant us the maximum amount of points ie. our answer is 8.4 whereas the actual ...
by Alan Cornejo 1a
Sun Oct 06, 2019 10:13 pm
Forum: Limiting Reactant Calculations
Topic: Steps to Finding the Limiting Reactant
Replies: 3
Views: 52

Re: Steps to Finding the Limiting Reactant

You only need to use the molar mass of one reactant to find the product, so you can keep the molar masses of the products separated. First, convert the grams given of a particular reactant to moles. Then, use the molar ratio of the balanced equation to determine how much of a particular product is ...
by Alan Cornejo 1a
Sun Oct 06, 2019 10:07 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Theoretical vs. Actual Yield
Replies: 38
Views: 470

Re: Theoretical vs. Actual Yield

Actual yields will be less than theoretical yields due to side reactions that can occur, some products could stick to the sides of the reaction container, and impurities that are bound to happen during almost all chemical reactions. Hope this was helpful/answered your question! exactly ! There are ...
by Alan Cornejo 1a
Sun Oct 06, 2019 10:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 141
Views: 3648

Re: Advice from a Medical Student - Part II [ENDORSED]

Great and awesome to hear that you still think about and take time to give advice to students of a teacher you had so long ago. We all appreciate the advice and good luck to you and all your endeavours .
by Alan Cornejo 1a
Sun Oct 06, 2019 9:58 pm
Forum: Student Social/Study Group
Topic: Final Jitters
Replies: 97
Views: 20182

Re: Final Jitters

I think the best way to relax and get rid of the nerves is to just close your eyes and breathe, just focus on good and positive memories and experiences will enhance your mood making you happier, the happier you are the more willing you are to focus and do something, it will also help clear your min...
by Alan Cornejo 1a
Sun Oct 06, 2019 9:53 pm
Forum: SI Units, Unit Conversions
Topic: Sig Fig Mistakes
Replies: 17
Views: 179

Re: Sig Fig Mistakes

Typically the amount of significant figures used for your answer is determined by the amount gaven to you in the question. Usually it follows these rules
any non-zero digits are always significant.
Any zeros between two significant digits are still significant.

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