CHEMISTRY COMMUNITY

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He'll answer it at the review :) don't stress Lyndon is an excellent teacher!

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This is how I remember it, if the molecule looks like there is a ring on it, it is a chelate. What I mean by ring, is a string of atoms starting at the central atom, connecting to one another in a string type formation, and reconnecting to the central atom.

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Yes, during one of the workshops I was told we will need to memorize that whole table for the final.

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I think we're not allowed to because it doesn't fully show out the concept. This class is very conceptual, therefore the whole concept of each problem is expected to be shown in our work.

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The cisplatin example in class discussed the difference between cis-diamine-dichloro-platinum(II) and trans-diamine-dichloro-platinum(II). The cisplatin has two cl's on the left of the central atom (Pt) and two NH3's on the right of the central atom. The Transplatin (not exactly sure if that is how ...

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A Ka value is calculated by products being divided by reactants (products/reactants). Strong acids completely ionize in water, so there are no reactants left. This means the equation will be products/0. Any thing/0 is undefined. Therefore, strong acids can not have a Ka value.

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Generally, your objective is to make the structure have a formal charge of 0. But sometimes the overall structure will have a charge of -1, 1, or really any number. Sometimes it will be clear where the charge should be placed, but other times it can by places on multiple different atoms. This is whe...

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I am also extremely confused on this. Is this something we are going to have to know for the final?

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Claire Lo 3C wrote:Since there is a space between potassium and hexacyanidochromate (III), it indicates that potassium is out of the bracket.

K3 [Cr(CN)6]

I believe the potassium is out of the bracket not because of the space, but because it is a metal.

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I believe just naming them for now. More comes along in chem 14b I believe Lavelle said

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Hybridization depends on the # of regions of electron density. 2 regions of electron density = sp hybridization. 3 regions of electron density = sp2 hybridization. 4 regions of electron density = sp3 hybridization. 5 regions of electron density = sp3d hybridization. 6 regions of electron density = s...

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For part c the coordination number is 6 (en is bidentate) and d is also 6 (EDTA is hexadentate)

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Thank you guys! I truly appreciate it

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It depends on how many bonds there are. 1 bond=1isgma bond. 2bonds=1 sigma and 1 pie. 3bonds=1 sigma and 2 pie

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I believe it is 3, but maybe they are equal? I'm not entirely sure and am also wondering.

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I think it may have to do with the fact that in sigma bonds atoms can rotate. But I'm not 100% sure and am a little confused on this too.

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Yes, this will always hold true for what we are using them for in the p-block

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On the answer key it states B) may have lone pairs. How can this be if the structure is linear and not bent?

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So hydrogen bonds make the molecule harder to break apart? So then they have a higher boiling point?

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ml= -l to +l. so if l is 2 then ml= -2,-1,0,1,2.

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I also have the same question. This is confusing.

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You can only take it if you took a math course this quarter :(

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Why can only F, N, and O hydrogen bond? Are there exceptions to this?

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I think you're just supposed to know by the trend. Like electronegativity increases to the right and up the periodic table.

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You can tell how many orbitals there are by the l number. For example, the s has 1 orbital, p has 3, d has 5, and f has 7.

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I'm confused about this too. in some of the review sessions, they mentioned that there were only certain instances where the equation could be used. And you needed to know when.

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You have to focus on the formal charge to decide when to place a double bond. Whichever structure results in the lowest formal charge is the one you want.

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The 3rd period and after I believe it is.

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You only have to include additional resonance structures if it asks you to (One of the UA's said this today in a review session). As far as the formal charge goes, I think you should include it just to be safe, but I'm not sure if its always needed. It will help you to determine if your structure is...

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Are there exceptions to the ionic radius trend? Like any elements that don't follow it?

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Honestly I don't understand this either. It seems like there are so many exceptions to rules in Chemistry and it just makes no sense.

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I believe we do need to know 1C. On the syllabus, it says to read Appendix 1B, 1C, 1D, 1E. So we should probably know it if we were expected to read it.

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For resonance structures, do they have to follow the octate rule? And if not, when?

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I too am confused about this. On problem 1d.25, there is mention of a g subshell.

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The question asks "Why are s-block metals typically more reactive than p-block metals?" I think we discussed this topic a little bit in class today with how the size of them makes them react more? I'm not exactly sure though. Can someone by chance help?

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I am doing this week's homework on the quantum world. I think that is correct because the next section of homework doesn't really make sense yet.

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I always take pictures of the class slides. If you want them, just respond to this post with your email :)

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On problem 1D.23 I am having trouble. How do I begin to know how many orbitals can have the following quantum numbers in an atom? The concept, in general, confuses me, not just this specific question.

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Yes, they can be any of the 5 questions off the syllabus. it doesn't matter which ones you choose.

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In the equation E=hv, what does h represent? I know it is the number 6.63x10^-34, but I'm confused with what the number represents.

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When a question asks to calculate the De Broglie Wavelength, does that mean there is a certain wavelength that is specific to De Broglie? I thought it was just an equation to calculate wavelength in general, not a totally different wavelength. But the way some of these questions are worded it has me...

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It is 1 angstrom to 10^-10 m

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For this question, it says to list the types of photons of electromagnetic radiation in the order of increasing energy. Does this mean smallest to biggest?

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They are all due Sunday night. You can ask a question, make a post, respond to other people, etc.

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Why can't we use a graphing calculator on the tests?

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I too would like to know if there is a quicker way for these more complex reactions. I'm usually just stuck plugging in numbers for quite a while until I can balance them.

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On the syllabus, it says which homework problems we can pick from. What I do is read the sections the homework problems are in. That way you're reading the information that is imperative to do the homework and therefore do well on the tests.

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There is not a course reader. There is a required book though. It is titled "Chemical Principals the quest for insight" it is the 7th addition. You can purchase it in a bundle at the UCLA bookstore. The bundle will include a loose-leaf version of the book, online access to the book, and a ...

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The test will only be on the fundamentals. The first day it will be given out is Tuesday, October 8th in your discussion section. Every discussion will get it next week from Tuesday- Friday.

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What if the question doesn't have numbers in it? Should I just do it to 3?

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I took the 2.1 x 10^9 atoms of C and divided it by Avogadro's number, or 6.022 x 10^23. This gives you the moles of carbon because you are dividing atoms of carbon by atoms per moles, which leaves you with moles of carbon. You have canceled out the atoms.

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I just got the TI-30X IIS 2-Line Scientific Calculator. It was about $13. It seems like that is what most people have had for this course in the past.

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it seems like for the most part many of the problems are only to 2 sig figs.

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How are you guys showing your work? I just divided 630g.mol by 210 g.mol. I'm not sure if I should add units or if I should show any more work.

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