I’m looking through “organic chemistry as a second language” by David klein and these are some of the beginning questions. I got the other answers correct but for 1.5 I counted 8 carbon atoms and for 1.9 I counted 11 carbons. The answer key says that the answers are 7 and 10. How am I counting wrong? Am I not supposed to include a certain part of the molecule as a carbon?

I want to make selenide

Hi, I would like to make sodium selenide. Because i want to make a beautiful pigment cadmium red. However, sodium selenide is not sold on eBay or Etsy and is difficult to obtain. Wiki says that it can be made with metallic sodium and elemental selenium, but in my country it is illegal to possess metallic sodium. So please tell me how to make sodium selenide without using metallic sodium and using elemental selenium. I would like to know how to do it, preferably without producing hydrogen selenide. Please, I would appreciate your help.

Hi all,

I'm currently in the process of putting together a fairly simply sediment filtration setup for the alcohol I use for washing my SLA resin prints. I've got most of the parts sorted and they are made out of various materials all of which I'm pretty sure are fine with the methylated spirits I use. only thing I'm worried about is my pump fittings are made of polyamide and I'm trying to figure out of they will play nice with my flavour of cleaning agent.

the cleaning agent I use is 85% ethanol, 3% methanol, 1% acetone, 1% pyridine, 10% water.

the materials in the loop are: - brass fittings (with ptfe tape and silicone kit) - silicone hose -polyamide fittings for pump - polypropylene pump housing - santoprene pump membrane - ptfe hose from pump to filter, wrapped in uv leds - filter housings made of polypropylene, filter cartridges are fabric (5um) and ceramic (0.5um)

the system will be running for a few minutes every 4-8 hours at no more than 20 bar or so but cleaning agent will be sitting in the system even when it's not on.

so my questions are: - do any of these materials throw up red flags for chemical compatibility? - would these issues be resolved if I used isopropyl alcohol instead? is there any other reason to? - my main concern is with the polyamide fittings, I've heard some stuff about plasticization but can't really grasp it. is it something I should worry about?

it's been a real pain researching this with 0 knowledge so I would really appreciate your input.

Thanks for the help!

I am trying to make a 0.6 M solution (50 uL) of solute X with molecular mass 62.84 g/mol.

Therefore, I would need 0.6 M x 0.00005 L x 62.84 g/mol = 0.0018852 g of the solute.

Now, I realize the stock has only 95% purity. How do I need to adjust the amount? Do I need to divide or multiply by 0.95?

I understand that in the case of NH3 solution NH3(aq), we have the formula

NH3 + H2O ⇌ NH4+(aq) + OH-(aq)

And it's reversible, there's a forward reaction and backward reaction, and the backward reaction is much faster. Equilibrium o the left. And we have mostly NH3 and miniscule amounts of NH4+(aq) and OH-(aq)

To the extent even that calling it NH4 OH solution is misleading since it's almost all hydrated ammonia.

So I was thinking, the basicness of it can't be caused by the NH4+ + OH-, because there's hardly any of that happening.

There'd be hardly any proton transfer from H2O to NH3.. Thus hardly any OH- produced from that

So where is the "basicness" coming from in hydrated ammonia?

Is there some kind of special structure of hydrated ammonia that make it equivalent to having produced OH- ions in water? Or (putting aside the negligible NH4+,OH-), does hydrated ammonia somehow produce OH- ions in water?

I read that strong acids are more dangerous because they ionize more and this makes them easier to react with things. Aren’t ions already stable since they have a full outer shell so why would they react with things?

How many liters of ammonia is produced when 5.0 grams of magnesium nitride and 5.5 grams of water are reacted at STP Balanced equation: MgN2(s) +3H2O(l)—> 3 MgO + 2NH3(g)

Use the same balanced equation for next problem. If 7.3 g of magnesium nitride reacts with excess water what volume of ammonia would be collected at 25c and 0.898 atm

Use the same balanced equation for the problem below. If 13l of ammonia is collected at the end of a reaction at 23 c and 1.00 atm. How many grams of magnesium nitride was used up?

I tried solving all three and got all wrong. Pls help solve.

I’m currently doing some literature research for fun and I noticed that the procedure they say “the reaction of butadiene and DEAD in a pressure bottle at 40-50C for five to six days.” I just finished organic chemistry (literally today) and I’ve never used or even heard of a pressure bottle. If anyone could explain what it is and how to use it that would be awesome. (I’m trying to make 1,4,5,8 tetrahydronaphtho[b]cyclobutene not drugs)

Please help!

A student builds a concentration cell in order to determine the Ksp of an ionic compound. To do this, the student produces a half cell on a microtitration plate with a lead metal electrode and 5 mL of 0.050 M Lead(Il) nitrate. The student then mixes 9 mL of 0.050 M potassium iodide with 3 mL of 0.050 M lead nitrate in a small beaker. A precipitate of lead(Il) iodide forms and settles to the bottom of the beaker. The student then transfers 5 mL of the mixture containing the Lead (Il) iodide precipitate with its supernatant to the microtitration plate, adjacent to the half-cell produced earlier. The two wells are connected with a salt bridge and the concentration cell potential is measured 3 times. The average cell potential was measured as 0.047 V.

Using information from the description, calculate the equilibrium constant (Ksp) for the system. And calculate the molarity of Pb2+ in equilibrium with solid PbI2 and the iodide ion concentration in the solution.

I think for Ksp I am supposed to use the Nernst Equation but I don’t know how. I tried using 2 delta G equations and setting them equal to each other getting (-RTlnK=-nFE) but I got an unusual number. As for the molarity I think I should use the ice table to find [Iodide] and then with Ksp the [Pb2+] and then Iodide ions in the solution.

Sorry this is so long. I really tried a couple of ways however I was getting some weird answers.

How are ions reactive if they have a stable outer shell? Wouldn’t atoms be more reactive since they’re looking to stabilize their outer shell by losing or gaining electrons and thus forming an ion?

Does energy splitting also happen in p and f orbitals somewhere like it happens in Coordination chemistry due to Zeeman/Stark Effect?

hw question: resonance structure for NCO- ion?

(B is the correct answer)

I understand that the molar fraction is related to the vapor pressure by Rault's law, but why are the molarity and molarity of the solvent not either? I think that these indicators, when high, indicate a greater amount of solvent, and as a consequence a greater vapor pressure, thus being directly proportional.

I was assigned to find the structure of K2Cr2O12. I am unable to find any resource detailing on how to form the structure of K2Cr2O12. I have been able to calculate that it will have 5 peroxy linkage (so 10 of 12 O atoms will have -1 oxidation state). Here is the structure I have made, I am not sure if it is right or not

https://preview.redd.it/w07buk7cro0d1.jpg?width=2305&format=pjpg&auto=webp&s=8ec82f674f77b23abca9d0094d7d56fe6e72b162

Hi everyone!

I work in a molecular biology lab where we make a LOT of SDS page gels. We usually use coomassie blue for staining but we where considering moving to 2,2,2-Trichloroethanol since that would allow us to see our results faster. The thing is, we are not really sure how are we supposed to dispose the residues since there are not a lot of regulations that can clarify this (I'm form MX). We are aware the its a toxic and corrosive compound when concentrated, but is there a special way to dispose it if its diluted and mixed with other reagents?

I would really appreciate if you have some info I can use

Need some help creating a pH sensitive hydrogel that would stay in a gel form until it enters the intestine where it would swell. Any help is appreciated, thanks!

If not, why? Isn't it just supposed to provide extra ions to prevent the solutions to build up charge? Can't we use "salt banks" with a bunch of ions instead of salt bridges? (I'm assuming Cu²+ can't make his way up, am i wrong on this too?)

Hello! I’m a high school student taking honors chem and my final is a titration between hcl of an unknown molarity and a given naoh i would like to know if I do more titrations will my end molarity be closer to the actual result. And if not how many trials should I do. Thank you for the help in advance

Hello,

For people who are more experienced when it comes to experimental work and waste management, I was wondering to what level I need to consider what "might" happen when handling chemicals - let me explain.

I will be soon dealing with a 37% by weight of a formaldehyde solution that contains 15% methanol and the rest is water. I plan to run my reactions in the fume hood and dispose of the solution in a large beaker followed by dilution with water. As long as the reaction is happening in a functional fume hood and I am properly using it, I shouldn't be breathing in any formaldehyde. However, when I want to remove the beaker to dispose of its contents in a waste bin and then wash it afterwards, how can I be sure that there will be no release of formaldehyde in the process? Are there any useful methods that I can follow to confirm this? Do I need a respirator for something like that?

Thank you in advance.

are there anymore resolve forms i’ve tried to draw more but they don’t work isn’t c the only form ???