CHEMISTRY COMMUNITY

Arlene Linares 3A

Can someone explain lone pairs to me?

Arlene Linares 3A

Any techniques to memorizing this?

Arlene Linares 3A

How do we figure out the AXE formula? I am still having trouble with this.

Arlene Linares 3A

Instead of using the formula, a shortcut in finding the formal charge is (number of valence electrons - number of the dots/number of lines). Here is a good youtube video I found explaining how to use the shortcut method! Hope this helps! https://www.youtube.com/watch?v=38fSDZypRB0 Thank you for the...

Arlene Linares 3A

Daniel_Frees_1L wrote:Its good to know the trends either way. Electronegativity, electron affinity both increase up and to the right. Atomic radius increases down and to the left

Thank you I was wondering about that because I understood left to right is positive and down is negative.

Arlene Linares 3A

An ion-ion bond would be an ionic bond, which is the strongest type of bond. This is because it is based on the transfer of electrons, whereas an H bond is more like an electrostatic attraction between a proton and lone pair. This is also evidenced by the high melting/boiling points of ionic substa...

Arlene Linares 3A

Vana Mirzakhani 3G wrote:Lone pairs have great repulsion strength from one another, always trying to move as far apart as possible while keeping an equally distributed distance from the central atom.

Thank you

Arlene Linares 3A

Alexandra Ortega 4D wrote:I don't think we will need to draw hybrid orbitals, but I am not sure. If we do. You would just use the diagram for the valence electrons of the central atom and show that the orbitals can be hybridized, or mixed, with each other to form sp or spd hybrid orbitals.

Thank you

Arlene Linares 3A

Ricky Ma DIS 4I wrote:Just think about the net dipoles and whether they cancel. You have to take in account the shape of the molecule.

Thank you for the information.

Arlene Linares 3A

Schuyler_Howell_4D wrote:Hybridization is important for bonding. You "mix" the orbitals together to visualize and determine how any valance electrons area available for bonding.

Thank you

Arlene Linares 3A

Xiangkun Shi 3E wrote:VSEPR theory applies to gases just as it applies to other molecules. For example, CH4 is a gas that has a tetrahedral shape and NH3 is also a gas that has trigonal pyramidal shape.

How can you memorize this like the names?

Arlene Linares 3A

Brice McKeown 3D wrote:Why is it that molecules with the same VESPR formula and lone pairs present have different bond angles? For example, look at the VESPR formula AX2E. O3 has bond angles of 116.8, but SO2 has bond angles of 119.5.

I see thank you.

Arlene Linares 3A

Bond angles are determined by the largest angle between to atoms in a molecule. It is dependent on how many bonds are in the molecule. For example, a molecule with two bonds coming off of the central atom will be linear, as a 180 degree angle is the largest possible angle between these two bonds. T...

Arlene Linares 3A

I think we will because you can't get make up extra significant figures. We have to get our answer from what data is available to us. If we get it wrong do you think we will still get partial credit for trying? I think we will as long as our answer is relatively close to the actual answer. Awesome ...

Arlene Linares 3A

I'm having trouble even finding a way to post in this forum. Can someone tell me where/how I can post a question? I agree I am having trouble with that too but in the upper left side with the three lines next to "Quick Links" shows a tab that you can view "your posts" So you go ...

Arlene Linares 3A

Zubair Ahmed 1E wrote:
Arlene Linares 3A wrote:For the midterm, does anyone knows how much the units are worth when graded?

I believe both units and sig figs are each worth one point.

Thank you

Arlene Linares 3A

alanaarchbold wrote:as the intermolecular attraction increases, vapor pressure decreases

Thank you for the information.

Arlene Linares 3A

I am a bit confused about the stable condition and the equation used to calculate it. Is a molecule or atom the most stable when it's Lewis Structure is equal to zero or is it the most stable when it is equal to the charge? Like for [SO4]2-, is the molecule most stable when the Lewis Structure is e...

Arlene Linares 3A

How many points was the FC worth on the midterm?

Arlene Linares 3A

Alyssa Parry Disc 1H wrote:Depending on the order of the reaction which should be given, you would use the integral of the rate law equation.

Good to know thank you for the information.

Arlene Linares 3A

I will discuss this in class tomorrow. AVERAGE RATE = (CONC(t2) − CONC(t1))/(t2 −t1) = ∆CONC/∆t INSTANTANEOUS RATE = −(d[R])/dt OR INSTANTANEOUS RATE = (d[P])/dt AVERAGE & INSTANTANEOUS RATES CAN BE DIFFERERENT FOR THE INDIVIDUAL R & P. THINK OF THEM AS THE EXPERIMENTALLY MEASURED RATES (CO...

Arlene Linares 3A

For the midterm, does anyone knows how much the units are worth when graded?

Arlene Linares 3A

emilyn1999 wrote:Yes, the more negative atom will be the more electronegative atom since they want to attract electrons to fill their outer shell.

So when they attract the atoms, will they become positive or stay negative?

Arlene Linares 3A

In ionic bonds, metals and non metals either gain or lose electrons to achieve the electron configuration of the nearest noble gas. Thus, the transfer of electrons leads to an octet of electrons (although there is an exception for H, He, Li, and Be). Main group metals form cations. They lose s and ...

Arlene Linares 3A

Yes! I believe that your assumptions would be correct based on what Professor Lavelle taught in lecture. He introduced the concepts of correcting BOTH the covalent and iconic models. For covalent models, he discussed the fact that electron pairs in covalent bonds may not be equally shared all the t...

Arlene Linares 3A

Beatrice Petelo 1F wrote:I find completing practice problems extremely helpful! Try to do all the hw problems and other problems in the textbook. Also, reviewing the tests and going over the problems again and your mistakes.

This is good advice thank you

Arlene Linares 3A

Katie Sy 1J wrote:I tend to just use the whole number listed on the periodic table to make sure my answers are exact as possible, but if it's a super long number, I usually stop after 3 decimal places

That's helpful to know thank you

Arlene Linares 3A

Reading Fundamentals in the textbook before the ones assigned were extremely helpful as well. I felt much more prepared after I read fundamentals A-D specifically. Also, just reading the textbook provides more background knowledge that helps understanding the course reader as well. Would you recomm...

Arlene Linares 3A

Just to add on-- Crash Course on Youtube is great for conceptual chemistry and overarching themes, and really helps with understanding the "greater picture" when it comes to some concepts. If you are looking for more step-by-step instruction with worked out examples, I'd highly recommend ...

Arlene Linares 3A

Just to add on-- Crash Course on Youtube is great for conceptual chemistry and overarching themes, and really helps with understanding the "greater picture" when it comes to some concepts. If you are looking for more step-by-step instruction with worked out examples, I'd highly recommend ...

Arlene Linares 3A

Sarah Jeong 4F wrote:Hi Matia,
I think in terms of sig figs for constant, just copy the full number from that is given on the formula sheet.
But for the actual final answer, use the sig figs of the numbers that are given in the question.

Thank you the info

Arlene Linares 3A

Matia Kim 1B wrote:In terms of given variables (e.g. speed of light), how many significant figures is recommended to answer a problem?

good question to ask didn't think about this.

Arlene Linares 3A

Chem_Mod wrote:1. Click "Quick links" top left
2. Click "Search"
3. In "Search for author" type: Chem_Mod
4. Click "Search" button at bottom of page
5. All Chem_Mod posts are listed starting with most recent.
6. Enjoy the informative reading!
:-)

thank you very much

Arlene Linares 3A

Chase Yonamine 1K wrote:1mmol is equal to 1x10^-3 mol. the m in front mmol means milli or 10x^-3.

Thank you

Arlene Linares 3A

Justin Le 2I wrote:I think we will because you can't get make up extra significant figures. We have to get our answer from what data is available to us.

If we get it wrong do you think we will still get partial credit for trying?

Arlene Linares 3A

Ismail 1F wrote:Yes, you can use Avogadro's number to convert to formula units.

so that will be the only number we use if it says that?

Arlene Linares 3A

Meghanhe1l wrote:Hello, I am wondering if we are still handing in our 7 homework questions on Friday, or if we are now handing them in during our discussions. Thanks!

Yes, we need to turn in our homework every time we have discussion now.

Arlene Linares 3A

Rachel Chau 1L wrote:does anyone know if we need to get test materials from the student store

No, we do not just a pen and a scientific calculator.

Arlene Linares 3A

I attended a chemistry study session where I was told there would only be about 3-4 questions, but most likely with multiple parts. I was also told that really studying and understanding what is listed in Outline 1 would help us on the test! I don't know how strict they'll be on grading though:/ Ye...

Arlene Linares 3A

So I keep hearing different responses from different people and I can't seem to find the answer on the syllabus or website: Do we have to have 3 posts for credit per week, or 1? I was originally told 3 by a classmate, but then another classmate said we only need 1... Replying and putting your own p...

Arlene Linares 3A

I agree I wonder if they are extra credit that would be very helpful but the professor hasn't mentioned nothing about extra credit.

Arlene Linares 3A

Is there any restriction as to how many questions we can answer from each section? ( only one question from E, only one from F, and so on) or can i answer any number of questions i want from any section as long as i end up submitting seven questions? Yes, you can pick any 7 questions from the weeks...

Arlene Linares 3A

Isabel Nkd 4D wrote:Can you clarify if its 2 points max. per week or 3 points max. ?

Thank you!

It is actually 3 points per week, so if you post three times either your own or comments you will get a point.

Arlene Linares 3A

charlotte_jacobs_4G wrote:I have been writing at least part of the question out on the homework. I find that if helps me review and remember what the question was asking without going all the way back into the book.

Thank you. I did not think of this and it does sound helpful to review what you are learning.

Arlene Linares 3A

Sollie1G wrote:Have you heard the one about a chemist who was reading a book about helium?
He just couldn't put it down.

AHAH this one is funny as well.

Arlene Linares 3A

Sollie1G wrote:What kind of dogs do chemists have?

Laboratory retrievers

Lol, this one is really good too.

Arlene Linares 3A

mitalisharma2B wrote:Did you know that oxygen went for a second date with potassium?
How did it go?
It went OK2!

This one is really funny and creative.

Arlene Linares 3A

Anne Kim 3F wrote:I'm having trouble even finding a way to post in this forum. Can someone tell me where/how I can post a question?

I agree I am having trouble with that too but in the upper left side with the three lines next to "Quick Links" shows a tab that you can view "your posts"

Arlene Linares 3A

Raquel Rodriguez wrote:Do you guys know when our first test is?

In the website, there is a tab that says "Test and Exam Schedule" but the first test will be on October 9 in your discussion section.

Arlene Linares 3A

Thank you so 3 posts throughout the week will equal 3 points so one for each.

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