javagamer

I'm looking for the mechanism for the reaction which converts a benyzlic carbon (with a hydrogen) into a carboxylic acid using MnO4-. Googling has yeilded several sites mentioning the reaction, but none explaining the mechanism and I'm not sure where to look. I was told the mechanism involves radicals, but I know nothing more than this. Can anyone help?

Thanks enthalpy, that's just what I was looking for.

I'm curious whether or not it is possible to make a vacuum by taking a rigid, hollow sphere and forming a vacuum inside of it. Presumably this is possible if you just assume the material it is made out of is infinitely strong and rigid (it just needs to weigh less than the equivalent volume of air). However, I'm curious if this is possible with any materials we know about.

I considered that, but increasing g would only decrease my answer and I'm already one below what it's looking for. However, unless there's some value of g < 9.8 I'm pretty sure that's not it. Turns out I had frictional acceleration wrong because I wasn't taking into account the angle. The acceleration from friction should equal -g * u * Cos(D) which would make my final equation be: distance = V^2/(2 * g * (Sin(D) + uCos(D))) Credit goes to Capn_Refsmmat who helped me on IRC.

Hi, I have some summer physics work to do online and I've come across what I believe to me a mistake in the site where I do the problems. However, before I send the teacher an email I want to be sure I'm not making some simple mistake. The question in question is #2 at http://wps.prenhall.com/esm_giancoli_physicsppa_6/16/4351/1113975.cw/content/index.html. Note, the numbers involved in the problem change every time (except for the angle in #2 which is always 30 afaik). The equation I've found is: (V^2)/(2 * g (Sin(D) + u)) Where: V is the starting Velocity, g is the (positive) acceleration from Gravity, D is the angle in Degrees, and u is the kinetic friction coefficient. To find this I first drew up a force diagram and found the accelerations from the forces affecting the skier. Gravity: -g * Sin(D) Friction: -g * u I then combined these to get -g * (Sin(D) + u) Then I took the equation F^2 = V^2 + 2 * A * D Where F is the Final velocity and D is the Distance Since I want the furthest the skier traveled I set F to 0 and re-arraged the equation to solve for distance. This gave me: D = V^2/(-2A) I plugged in the accelerations I found to get D = V^2/(2 * g * (Sin(D) + u)) This works for the first question when I have no friction (so u = 0), but I always get one below the answer for part two. So, did I make a mistake or does the script that they use to compute the right answers make a mistake? For those who don't want to click the link here are some sample numbers. 20.5 for the starting velocity, 30 for the angle, and 0.13 for the frictional coefficient. Apparently the right answer is 35 yet I get 34.

Hi, Just thought I'd mention that Google's sponsoring a pretty cool contest run the the University of Waterloo to write AI for a tron game. You can write code in just about every language out there and with the starter packs it's really easy for someone who only knows a little programming to get started. You can check it out at http://csclub.uwaterloo.ca/contest/index.php. It runs until February 26 so there's plenty of time. As of right now I'm in 21st place (http://csclub.uwaterloo.ca/contest/profile.php?user_id=1556) and I'd love to see how everyone else compares. Good luck to everyone who tries!

Hi, I'm planning on making some concentrated ammonia solution and I'm a little confused as to the math. I plan on heating some store bought ammonia, which I already determined is 10%, and bubbling the gas through water. What I'm confused about is how to convert from w/v since the density of water changes depending on how much ammonia is dissolved. Do I need to know the density of 10% and 35% (that's saturated, right?) to figure this out? Anyways, any help is appreciated. Edit: I think some of the trouble I'm having is from wikipedia's article on ammonium hydroxide. It says "At 15.5556 °C, the density of a saturated solution is 0.88 g/mL and contain 35% ammonia by mass, 308g/L w/v, (308 grams of ammonia per litre of solution) ...". I was confused because I thought if it's 35% then there would be 35g/100ml, though now I see that it's at 15.6 °C so that probably clears that up. Merged post follows: Consecutive posts mergedAlright, I think I figured most of it out. 10% solution means there's 10g of ammonia in 100ml FINAL solution. Now I just need to know how to go the reverse, figure out how many grams of ammonia I need to dissolve in a given volume of water to get a given percentage solution. Anyone able to help?

What was wrong with it? A lot of the appeal is how easy it would be to do and a horizontal wall thing would be far too much for me to set up.

Hi, the idea just popped into my head that it would be pretty cool if I could harness a large weather balloon to myself so that I could reduce my percieved weight to about 10% of what it normally is. Doing the math (or finding someone else who did it already, and extrapolating from there) I found I would want somewhere around 2,000 cubic feet of helium to get very roughly 90% of my weight as lift. I found several sites which sell weather balloons with an inflated diameter of 16'. Doing the math I discovered that should be able to hold 2,100 cubic feet of helium, which is still not enough to lift me off my feet. Here's where I come across the first problem, where can I possibly get 2,100 cubic feet of helium? If balloons are sold this big I'm assuming there are places which sell this much helium, but I've yet to find any. I'm thinking I'm missing something, but I can't figure out what. My next concern would be wind. If I have a 16' balloon a few feet above me I'm guessing should there be a gust it would probably have a lot of force and likely be able to push me around or maybe even off my feet. Should I just got for lifting only 2/3 of my weight and get a smaller balloon, or will wind be rather negligable assuming I'm not doing this in a storm? Next, I've considered hydrogen rather than helium since it's apparently much cheaper and provides slightly more force. Now obviously it presents a fire hazard, but if the balloon contains exclusively hydrogen then it can't explode, can it? Should it somehow be ignited within 5' of me would it just be a wave of heat and a pop, or would it be more like terrible burns and hospitalization? Finally, I currently would plan on using one balloon since it appears cheaper and would be the most efficient use of volume. The only downside I see to this is that should it pop all the lift is gone instantly. I wouldn't consider this a major problem though since I just plan on running around and jumping rather than flying through the air. However, I'm well aware that I could have overlooked something. So, basically I want to know whether this is something I could possibly do (safely). If I do manage to pull this off pictures will most certainly be posted.

Yeah, I know, everytime I overshoot and add base I end up creating more salts in there which my plants can't enjoy. I was hoping there was some mathematical formula I could use to find how much of an acid I would need to add rather than through experimentation since I don't have a very good means of measuring pH. All I have is a pH meter which appears to work to .1 of a pH, though it moves around a lot before it settles on a value. Also, ammonium sulphate sounds like a good idea, thanks.

I think the chloride ion is actually harmful now that I think about it. IIRC it sucks water out of the plant through diffusion, though I guess most ions would do that, right? Also, might household strength vinegar be good enough? I don't have any GAA yet.

Hello, I'm growing some plants hydroponically and I've realized the pH is tending towards basic, while it should be in the 5.5-6.0 range. I'm wondering how I could best move it there with easily attainable chemicals, and it keep there. My previous method consisted of mostly adding in a splash of pH down solution (which I believe is just sulphuric acid) we have sitting around, then adding a splash of baking soda when I end up overshooting my target pH (I have at most 5 gallons of water in my hydroponics system so overshooting isn't very hard). Obviously, this isn't a very good method since it's very error-prone and I'm running out of pH down. My first question is: What could I use for pH up and down? For pH up I think baking soda is probably the best choice since it's certainly available, cheap, and as far as I know not very harmful to my plant. For pH down I'm more unsure. I have HCl, but it's from a hardware store so I have no idea how harmful the impurities might be. I also have hardware store sulphuric acid which is obviously very impure, but I might be able to clean it with some activated carbon. I also have some technical grade sulphuric acid from Fisher Scientific, but I'd rather no use that since it's more limited. My second question is more math involved. Once I have a pH down how much would I need to add to get the pH in my target range? I'll be replacing the water with distilled water soon, so we can assume a pH of 7.0 . Now, I probably won't have it filled completely with 5 gallons, but I think assuming it is 5 gallons and then that I want a pH of 6.0 will probably work. So once I have an acid how do I determine how much I need to add to bring the pH of 5 gallons of distilled water to a pH of 6.0? My final question is: How do I keep the pH in this range? I don't know a whole lot about buffer solutions, but I have a feeling they could be useful. I also read on wikipedia that the pH of carbonic acid in equilibrium is between 5.5-6.0 so would there be any way to constantly bubble CO2 through it to keep the pH down? I'm using a DWC system so air is already being bubbled through. Any help is appreciated!

Hi, I recently managed to stumble across what is in my opinion a very funny game. It' called Forum Warz (http://forumwarz.com/) and it's a browser-based MMO parodying internet culture (with focus on trolling). However, because of the subject matter the game can be very NSFW (no pornography though). It's a game intended to be played a little every day so there are limits in place to prevent you from beating it all in one day. However, it's a great way to kill time. Even if you're not a huge fan of the game, one of it's multiplayer mini-games is incredible. It's called INCIT (http://www.forumwarz.com/incit) and basically you get to are presented with a random picture and you fill out a motivational for it. After 3 minutes everyone playing votes for which they think is the best. This is another incredible way to kill time. I think this game is certainly worth checking out and I'd love to hear what others think of it. Just another reminder, it can be very NSFW. Also, don't play if you're easily offended. (I *think* this is allowed by the rules, but if not just delete it)

Hi, I've been looking for some small experiments to do to occupy my time while I wait until I have enough money to afford the distillation set I want to do more interesting things. While browsing around online I came across bubble solutions and realized there's quite a bit involved. Bubble artist Keith Johnson has a pretty basic page about the construction of bubble mixes located http://homepage.mac.com/keithmjohnson/soapbubbler.com/page2/page8/page8.html. He also has a page listing a lot of patents involving bubble mixes at http://homepage.mac.com/keithmjohnson/soapbubbler.com/page16/page17/page17.html. I'm curious what could be changed around to improve upon this. What would happen if you used a non-water solvent like alcohol or DMSO? Are there any easily synthesizable polymers or surfacants that might be useful? What interesting properties could be given to bubbles (I saw one patent which talked about bubbles bursting into strings)? I think there's a lot of stuff that could be done here and I'm hoping it can occupy my time for a while. Anyone have any suggestions? Also, how hard is it to make Hydroxyethyl cellulose? I found a paper titled "Homogenous Synthesis of Hydroxyethylcellulose in NaOH/Urea Aqueous Solution" that sounds pretty easy, but I've only read that abstract so far.

Oh wow, I totally didn't see the max head of that pump, that makes things easier. Thanks!

Hi, I'll start by stating my intentions. I'm looking at buying a water pump to power a vacuum aspirator I have bought (link) and I want to make sure it can put out 30 psi so I can get a good vacuum from it. At the moment I'm looking at the water pump located at bottom of https://cheappumps.com/products.php?al=inpumps. It says it has a flow rate of 130GPH. My question is, is there any way to determine the pressure from this? It seems that there must be some way, but my understanding of physics is curently limited (just taking high school physics now). Any help would certainly be appreciated.

Oh, well that explains it. Thanks for clearing that up

Ah, I misunderstood, I thought the desensitization occured by reducing the signal sent as opposed to reducing the sensitivity of the receptors. How come the rats never got tired of pressing the lever then? Did they just not have enough time to get desensitized to it?

I was under the impression that the rat experiment proved that that doesn't happen, but now I realize that it mostly likely didn't happen because the impulse was being sent by an electrode rather than the brain itself. Thanks for clarifying, so I guess that makes everything else implausible?

What I believe he's trying to say is first, that pleasure itself isn't something people can get bored of/become used to, and he ackowledges that society becoming weaker is a problem that needs to be worked out, but it is possible to have different shades of pleasure and keep people motivated rather than being "blissed-out" as he puts it. It's possible I'm not understanding this properly though.

He seems to debunk that here citing the rat experiments where rats would constantly hit a switch which sent a shock to their brain, they never got bored of it. He also mentions that people who are depressed don't become insensitive to sadness. If you scroll down a bit he seems to tackle your other point about society becoming weaker. Can't really argue with that. Even if some of his ideas are pretty stupid though, what he proposes in The Hedonistic Imperative sounds reasonable and well researched to me. Though I certainly will be even more skeptical b/c of that article.

Hi, I've come across "The Hedonistic Imperative" (hedweb.com) and reading some of the stuff it certainly sounds interesting. It's a site about paradise engineering created by David Pearce, a British philosopher and abolitionist (believing in the abolition of suffering). I'm not too sure what to think of it at the moment, at first the idea sounds rather revolting, but the more I read and think about it the better it sounds. My mind's not totally made up yet, I'll probably be reading this for a while. So, what do all of you think?

I might be able to make it, I'm about an hour away. Getting my license in a few months so I'd need a parent to get me there, but it's possible.

I always use Spam Cop at spamcop.net, I'm hoping it's helping me, but I'm not sure. I seem to somewhat consistently get spam from one person, but that's it.

I'm pretty sure chlorine is greenish-yellow, though that's only in high concentrations.