Chemical Forums
Specialty Chemistry Forums => Chemical Education and Careers => Topic started by: mike on September 22, 2005, 02:34:29 AM
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My favourite chemistry experiment from high school/first year university level chemistry was probably extracting the coloured components from spinach and running a thin layer chromatogram of them. I think because it was colourful and relatively "consumer based" chemistry I found it interesting.
I now have a job introducing new experiments into a first year general chemistry program and it is quite fun. I have found literally thousands of experiments uploaded on the web and in educational journals covering every topic imagineable.
I would love to know what kind of experiments people on this forum remember/enjoyed and why. Do you think there are certain types of experiments that excite students about science more than others?
Cheers, Mike
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You might find this site interesting especially the lectures.
http://cavemanchemistry.com/
http://cavemanchemistry.com/ch104.html
http://cavemanchemistry.com/lectures.html
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Cool, yes these are the types of things I think make chemistry/science interesting. Looks like a great site I will have to sit down and have a decent look at it in a bit, from the quick look I have had seems very interesting.
Thanks :)
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We didn't do much experiments in high school, but one I remeber being interesting was Aspirin synthesis. Quite simple reaction creating a pure drug component, showed how simple chemistry is in theory, but not quite so easy in practise.
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The presentation that I remember most were demonstrating the effect of surface area on reaction rate (a lesson I haven't forgotton!)
Cheesy and insignificant as it sounds, the teacher took some lycopodium powder..put it in a pile, and lit a match and put it on top. The powder kinda fizzled a tiny pit...but the flame got extinguished. Then he took some lycopodium powder in his hand, and held a lit match between his fingers. He jerked his hand upward so the powder would spread up and outwards, passing the match in transit (obviously with a greater surface area). The powder combusted into a short-lived ball of fire...like 2 feet tall and one foot wide. It was AMAZING!
I also remember when he took a particular crystal that could exist with or without a water of crystallization...He heated the hydrated one to dispell the water and it actually changed colour (neat eh? I know now that that's ligand chemistry :P)...
Anyways he had one guy put it in his hand, and then he put a tiny drop of water on it. The crystal readily recrystallized, and of course gave off some heat in the process...I remember the guy holding the reaction in his hand uttering an expletive lol...Heat of hydration is AWESOME (is that what its called)?
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I always got a big kick out of the alkali metal and/or halogen reactions. There's just something about them that is always fun to watch. Whether it's an alkali metal in water, or a metal burning in a pure halogen atmosphere. (I really enjoyed aluminum and iodine and aluminum and bromine). I guess the real kick out of those experiments was the fact that they weren't done all that often as the halogens and alkalis are incredibly reactive.
Another neat experiment was done in college where we synthesized nitrocellulose and nitroglycerine. Now this was done on a microscale where one cotton ball was nitrated and one mL of glycerine was nitrated, but it was still neat to see the stuff beforehand where it would barely ignite (cotton), or do nothing at all (glycerine). Then it was nitrated and suddenly the cotton immediately flared up and dissapeared in a ball of fire, and the glycerine just went 'POW' and it was all gone.
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My favorite experiment was done in my garage with a microwave.
I took a piece of cork and stuck a toothpick in the top of it. I then place that in the middle of the microwave.
Then I took a large Pyrex beaker, i think it was 2 liter, and coated the inside with honey and salt.
I then light the toothpick on fire, placed the pyrex beaker over the top of it and set the timer to 30 seconds.
After a few seconds, a glowing orange and red "plasma" ball was floating or clinging to the top of the inside of the beaker and swirling around.
Very cool, but dont expect the microwave to last for too long:)
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If only there weren't so many occupational health and safety issues with so many of the "fun" experiments, we could really spark students interest in chemistry. My father always says that experiments that go boom give students the wrong idea about chemistry. I think we need a balance of both types of experiments, visually spectacular as well as those that inspire thoughts of chemistry on other levels.
I think demonstrations like making nylon, lighting light bulbs from chemical cell, and the luminol reactions are all quite good in this respect. Liquid nitrogen demos are spectacular too, and I always loved dry ice when I was younger.
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My physical science teacher (Freshman year)took a mixture of soap and water and hooked it up to the gas jets. He then proceded to take 2 yard sticks; 1 with a flaming ball of alcohol/water mix in a napkin and the other yardstick he took the bubbles and proceded to light them on fire. All of this was to show us the consvation of energy and reactions. Sure this wasn't the safest thing but they hadn't installed the sprinkler system yet ;) .
Another cool thing he did that wasn't so dangerous was took he took a drained out egg and put 2 chemicals in it. He didn't tell us what he put in it for "safety" reasons but the reaction gave off hydrogen gas and the egg exploded under pressure. This demonstrated pressure.
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Ok so now I have tried dehydration of sugar with sulfuric acid and the thermite reaction for myself, and they are pretty cool. We are going to introduce these into the undergraduate labs, hopefully the students will be suitably impressed.
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My favourite experiment is the Marsh test (detection reaction for Arsenic)
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Ok so now I have tried dehydration of sugar with sulfuric acid and the thermite reaction for myself, and they are pretty cool. We are going to introduce these into the undergraduate labs, hopefully the students will be suitably impressed.
I did the sugar and sulphuric acid reaction too several weeks ago! I tried several different artifical sweetners and the same fianl product was seen with all of them.
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I tried several different artifical sweetners and the same fianl product was seen with all of them
What a great idea, I never even thought of trying artificial sweeteners, I will give it a go.
Do you think that syrup would work? Maple syrup or golden syrup, molasis? interesting!
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Since sulphuric acid is acting as a strong oxidizer. One would expect it to oxidize any hydrocarbon species to natural carbon.
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My favourite experiment is the Marsh test (detection reaction for Arsenic)
Ahhhh yes. The good 'ole Marsh test. We did that experiment in our toxicology lab. If I remember correctly, the presence of arsenic shows up as little dark spots in the solution, correct? I think one of the intermediates is the production of arsine gas which led to a bit of a scare in our lab. (One of the reaction vessels was erroneously taken out of the fume hood, and my nose was able to pick up on the rotted garlic odor. Oddly enough, nobody else noticed the arsine smell but me. Go figure).
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My favourite experiment is the Marsh test (detection reaction for Arsenic)
Do you do this as an undergraduate experiment? Is it part of a specific toxicology course or is it done in general chemistry? It sounds interesting, I hadn't actually heard of it until now.
Can you do "real" samples? like hair, or soil?
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Can you do "real" samples? like hair, or soil?
Of course! I analyze only real samples (my specialliy are minerals). I have analyzed dozends of real samples...soil, minerals, wood, alloys (e.g. an aluminium can), samples of metal (e.g. metallic lead to determine the percentage of antimony), coal, ashes, washing powders and so on....It's really funny to analyze real samples... and I think it's quite boring to analyze a mixture of salts made by the teacher.
If I remember correctly, the presence of arsenic shows up as little dark spots in the solution, correct?
Not really...the nacent hydrogen produced by Zn and sulfuric acid reduces the arsenic compounds to arsine, and the arsine is heated => AsH3 --------HEAT--------> As + 1.5 H2
You identify the arsenic "mirror" (Very thin foil of elementar arsenic) because of it's black color. By the way....I once smelled the arsine gas, and the rotten garlic odor is pretty disgusing. I smelled ti only once because the mineral contained so much arsenic that a huge amount of arsine was created, so that the fume hood couldn't remove the whole gas, but fortunately nothing bad happened. (a more disgusting odor is the H2Se Odor (Rotting radishes))
Do you do this as an undergraduate experiment? Is it part of a specific toxicology course or is it done in general chemistry? It sounds interesting, I hadn't actually heard of it until now.
Not really, I have 8 hours of analytical laboratory per week in my school, and If I have to analyze a sample I make several tests for many different ions....one of this tests is the Marsh test.
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OK guys, I need your help with something. I need to get a bunch of ideas for some really neat organic chemistry experiments. Preferably organic synthetic reactions covering such things as nucleophilic substitution, elimination, formation of C-C single bonds etc at a second year level. I would also like to hear what peoples experiences are with stereochemistry labs, are there any that stand out in peoples minds.
I have also come up with a list of practical skills that an undergrad organic chemist may need to learn:
*recrystalisation
*melting points
*yield calculations
*Buchner filtration
*use of dropping funnel
*reflux
*distilation
*drying (with MgSO4 etc)
*bioling point measurements
*separatory funnel
*rotary evaporation
*IR
*extractions
And maybe some general skills:
*Synthetic experiment procedure (measure -> react -> quench -> work-up -> purify -> characterise)
*lab journal
*lab report write-up
What do you other chemist think?
Mike
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My favorite organic chemistry experiment was making Nylon. :)
I even kept my final product. Shhhh... :shhh:
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In my o-chem lab we performed a two-step, diastereoselective synthesis of 1,2-diphenyl-1,2-propanediol from benzaldehyde. We first synthesized benzoin by coupling benzaldehyde to itself in the presence of thiamine and aqueous NaOH. Afterward we reacted the benzoin with MeMgBr to synthesize 1,2-diphenyl-1,2-propanediol. This step is diastereoselective beause of the Cram Chelate Rule (this was of particular interest becuase Cram was a professor at my school ;D). Unfortunately, the experiment didn't work when our lab performed it because lab support gave us the regular diethyl ether instead of anhydrous diethyl ether for the second step, so the Grignard reagent died :'(.
Anyway, if you're interested here's a reference:
Ciaccio JA. et al. J. Chem. Educ. 2001, 78, 531.
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*Synthetic experiment procedure (measure -> react -> quench -> work-up -> purify -> characterise)
I am writing from my old labjournals now:
How about synthesising Chrysantemic acid?
It is a five step procedure, you can do it in three or four days on the lab. You start with a lot of materials, and end up with a few micrograms :-)
Or synthesising Sulphadrug? There is some historic value in it too.
Or DEET (Diethyl toluamide)? An insect repellent. You extract it as a oil.
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I have two favorite experiments as an undergrad. In ochem lab I made a musk ketone as a "special project". It was a multi-step synthesis in which I was just puting substituents on toluene until there were no hydrogens left on th ring. I thought it was interesting to see the benzene ring peaks disappearing from my NMR each week. It was very cool. Also, we made alloys of copper and nickel in pchem lab next spring using cold boat fusion, or something like that at least. Then we performed xray diffraction experiments on it. That was awesome too. I can't wait to teach labs next fall. :)
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My favorite organic chemistry experiment was making Nylon. :)
I even kept my final product. Shhhh... :shhh:
About five years ago I still had mine too - but then I moved :(
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Burning Mg was always cool (well, rather hot actually). We were alowed to play with little bits to burn over the bunsen - the teacher used a gas jar full of oxygen to submerge the burning Mg in - obviosly alot brighter and more vigerous combustion. Against the health and safety regulations, I managed to get her to let me have a go in front of the class - nice, but a bit scary at the time. (we used to steal small strips of it to take home and burn... Hmm).
Yes, as mentioned already - sodium etc. in water is brilliant!
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I even kept my final product. Shhhh... :shhh:
Hmmm...one of my nasty classmates stole some nitrocellulose about one year ago.
However, he put the stuff in his schoolbag where it underwent self-ignition....you can imagine what happened...
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Or DEET (Diethyl toluamide)? An insect repellent. You extract it as a oil.
Have you ever put a really high concentration of it on a bug. Yayyy, a good way to grow a third arm. ;)
Hmmm...one of my nasty classmates stole some nitrocellulose about one year ago.
However, he put the stuff in his schoolbag where it underwent self-ignition....you can imagine what happened...
Was your classmate wearing his bag when it self ignited..
My physical science teacher made nylon for me. I asked him how they mad it randomly one day, and after class he showed me.
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Ok so here is a modified list of the practical skills that a second year organic chemist should have:
use electronic balance (for solids and liquids)
pipettes
transferring solids and liquids
tare
magnetic stirrer (stirring / shaking)
hot plate (heating / cooling)
water bath
steam bath
dropping funnel
reflux (air & water condenser)
dry glassware
following the progress of a reaction
precipitate product
collect precipitate by filtration
washing crystals
crystallisation
Buchner filtration
recrystallisation
distillation
separatory funnel
drying with MgSO4 or CaCl2
rotary evaporator
sublimation
evaporation
liquid/liquid extraction
hot filtration
decolourising charcoal
chromatography
melting point
yield calculation
boiling point
infra red
refractive index
1H and 13C NMR
UV/vis
mass spec
Fumehood
MSDS
risk assessment
Lab journal
Report writing
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Ok so here is a modified list of the practical skills that a second year organic chemist should have:
dropping funnel
Report writing
Are you sure funnel dropping is a usefull skill? I would rather go for funnel preserving :)
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Are you sure funnel dropping is a usefull skill? I would rather go for funnel preserving
haha :D yes good point. I think undergraduate students get quite good at dropping things. I used to love telling them how much things cost after they had broken them, poor students :D I am too mean.
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Was your classmate wearing his bag when it self ignited..
No! Actually, it self ignited during the Geography lesson :D ... he threw the burning bag (The bag was burning like hell! ) out of the window. Afterwards he jumped out of the window (we were having the lesson at the ground floor..) and put out the fire with snow.
Then he confessed that he stole the nitrocellulose and as a punishment he had to clean the stairs of our school for 40 days.... :o
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Sounds like a fun geography class.