Experiențe chimice

am deschis acest thread pt cei cu inclinatzii de genul acesta


deci
:cool: cine a mai fakut experientze cu H in combinatzie cu aerul  

sau cu Cl K  (clorat de potasiu)---asta e super belea...explodeaza shi fara sa ii dai foc!!

so bagatzi shi voi chestii dastea interesante

chiar nu sthie nimeni faze tari ?

Eu mai stiu chimie, dar doar in teorie.
Asta e o mare problema pentru invatamantul romanesc :@

vrei faze tari ? .... glicerina shi acid azotic... vezi ca e puternic exoterma.. tre sa faci asta (nu te sfatuiesc) intr'o vana de gheatza. rezultat? ceva periculos rau, trinitroglicerina... extrem de instabila... asha ca forget foc sau shocuri in jurul ei ca eshti bye bye. potzi sa imbibi tng in un carton mai gros / poros sau asbest shi sa faci diverse "poante" de prost gust... cu fitile... sau chiar fara. cartonul ala cu tng in el e ceva in genul dinamitei.

la fel, dar in loc de glicerina... cu toluen. reactzia e PUTERNIC exoterma, daca nu e racita explodeaza (fireshte). Atentzie, toluenul e FOARTE toxic. se poate obtzine in lab la orice scoala din benzen shi acid acetic (nu mai shtiu exact formula... parca asha era)

bafta,

PS. nu incerca asta acasa !

ah, vorbesc prostii, mi'am amintit acum....

toluenul ilo obtzii din benzen shi clorura de metil... CH3CL, cu catalizator de Aluminiu CL3. recatzia asta este "alchilarea Friedel Crafts"

Clorura de metil, o faci din Metan shi CL2

man, ai grija daca te bagi la d'astea... masca de protectzie... shortz solid, nu de carpa... manushi ... shi evident TOTUL sub hota

mai arty nu il mai invata pe asta la prostii ca stau la 2 case de el si ma arunca dreaq in aer

Drfan :stai dreaq in banca ta ca daca te pierdem ma bagi in datorii la astral

Amestecul de glicerina cu acid azotic   nu va duce la formarea de nitroglicerina. Chestia asta era valabila prin [gl]Insula Misterioasa[/gl] , in viata reala lucrurile fiind ceva mai complicate, implica mai multe substante, si conditii de lucru specifice.

Asa ca ... luati de faceti copiii, si lasati exploziile ....

Ok.. in urma insistentelor.. l-am redeschis INSA cu promisiunea ca discutia nu o sa se axeze EXCLUSIV pe explozii

Mai sunt si alte lucruri interesante in chimie...

Spre exemplu.. stiam ca exista un amestec cu rol de barometru !

Ai un recipient si in functie de presiune "lichidul" se coloreaza si se cristalizeaza diferit....

Stie cineva mai multe despre asta ?

damn, chiar mi-ar trebui asa ceva cand vreau sa merg la pescuit, nu ca as merge prea des...

aveam undeva un aliaj de metale care se topea sub 50-60 grade C.. o sa revin cat de curand merge pt lingurite la cafea

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BTW, H e de fapt H2 (hidrogen) iar Cl K e de fapt KClO3 (clorat de potasiu).
Daca vrei experiente interesante si relativ putin periculoase cauta la biblioteca (sau pe la vreun anticariat) o carte numita "Chimia distractiva" si alta numita "Ucenicul vrajitor".
In orice caz, te sfatuiesc sa te documentezi bine inainte de a face experiente chimice altfel le faci pe pielea ta.

Pana una alta mai poti incerca:

Na sau K (sodiu sau potasiu) + H2O (aqua chiara ). Inainte de a adauga metalul, pune cateva picaturi de fenolftaleina in apa. In urma reactiei (2Na + 2H2O ---> 2NaOH + H2) se va forma NaOH care iti va colora solutia in rosu si se va degaja si H2, la care poti sa-i dai foc.

KClO3 + S (sulf) ===> amesteca bine, dozeaza in capsule mici si "plezneste-le" cu ciocanul

KClO3 + P4 (fosfor - rosu sau alb) ===> la fel ... noteaza diferenta

Poti incerca deasemenea sa-ti faci singur praf de pusca sau petarde pentru Anul Nou ... totusi, nu uita, cine se joaca des cu focul se parleste pana la urma.

In chimia organica sunt de asemenea multe reactii interesante. Totul e sa-ti placa chimia ... si fizica si matematica si ...

Multe succese!

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Nu am timp sa traduc dar cred ca te descurci bine cu engleza.
Uite aici ce te interesa ... am inclus nu doar compozitia ci si un scurt istoric si bibliografie. Enjoy!

Admiral Fitzroy (1805-1865), as commander of HMS Beagle, participated in the Darwin Expedition from 1834-1836. In addition to his naval career, Fitzroy did pioneer work in the field of meteorology. The Beagle's instrumentation for the Darwin Expedition included several chronometers as well as barometers, which Fitzroy used for weather forecasting. The Darwin Expedition also was the first voyage under sailing orders that the Beaufort wind scale be used for wind observations.

One type of barometer used by Fitzroy was a storm glass. Observing the liquid in the storm glass was supposed to indicate changes in the weather. If the liquid in the glass was clear, the weather would be bright and clear. If the liquid was cloudy, the weather would be cloudy as well, perhaps with precipitation. If there were small dots in the liquid, humid or foggy weather could be expected. A cloudy glass with small stars indicated thunderstorms. If the liquid contained small stars on sunny winter days, then snow was coming. If there were large flakes throughout the liquid, it would be overcast in temperate seasons or snowy in the winter. Crystals at the bottom indicated frost. Threads near the top meant it would be windy. Take a look at the notes Fitzroy compiled on use of the barometer and thermometer.

Here are instructions for constructing a storm glass, described by Pete Borrows in response to a question posted on NewScientist.com, attributed to a letter published in the June 1997 School Science Review.

Ingredients for Storm Glass

2.5 g potassium nitrate
2.5 g ammonium chloride
33 mL distilled water
40 mL ethanol
10 g camphor

Dissolve the potassium nitrate and ammonium chloride in the water; add the ethanol; add the camphor. Place in corked test tube.

Mark Ford, who has been making storm glasses for years, emailed me to add that man-made camphor, while very pure, does contain borneol as a by product of the manufacturing process. His experience is that the synthetic camphor doesn't work as well as natural camphor, perhaps because of the borneol.

Mr. Ford advises dissolving the nitrate and ammonium chloride in the water, then the camphor in the ethanol. Next, slowly mix the two solutions (adding the nitrate & ammonium solution to the ethanol solution works best). It also helps to warm the solution to ensure complete mixing. Mr. Ford never uses a cork, preferring to seal the mixture in small glass tubes.

No matter what method is selected to construct a storm glass, the reader is advised to use proper care in handling the chemicals ;-)

The premise of the functioning of the storm glass is that temperature and pressure affect solubility, sometimes resulting in clear liquid; other times causing precipitants to form. The functioning of this type of storm glass is not fully understood. In similar barometers, the liquid level, generally brightly colored, moves up or down a tube in response to atmospheric pressure. Certainly temperature affects solubility, but sealed glasses are not exposed to the pressure changes that would account for much of the observed behavior. Some people have proposed that surface interactions between the glass wall of the barometer and the liquid contents account for the crystals. Explanations sometimes include effects of electricity or quantum tunneling across the glass.

Italian mathematician/physicist Evangelista Torricelli, a student of Galileo, invented the barometer in 1643. Torricelli used a column of water in a tube 34 ft (10.4 m) long. Storm glasses available today are less cumbersome, easily mounted on a wall.

Additional Reading

Admiral Fitzroy Barometer in Mahogany - This is Ezshop's description for a Fitzroy barometer, which includes a bit of history surrounding Fitzroy's storm glass.
Admiral Fitzroy's Remarks - This is a quotation from Fitzroy, regarding
use of weather glasses.
Barometer - This is Encyclopedia.com's entry for 'barometer'.
Barometer World & Museum - This specialist firm deals in and restores

barometers. Storm glasses are available.
Charles Darwin and the Voyage of the HMS Beagle - This is a collection
of annotated links.
Charles Darwin's Ship HMS Beagle Links - This is a collection of links
relating to Darwin and/or the Beagle.
FitzRoy and the Beagle - Access Excellence provides this brief
biography of Fitzroy, which includes a portrait and a schematic of HMS Beagle. Links to additional information on the voyage of the Beagle is provided.
Gadgets - Darwinism - New Scientist.com's answers to questions
about weather glasses provided much of the information used in this article.
Meteorology - This is the Encarta Encyclopedia entry, which includes
sections on physical characteristics of air, meteorological instruments, structure of the atmosphere, global circulation, clouds, precipitation, weather, history, and other topics.
Observation Over Work of the Device 'Storm Glass' - This three-part
series details Sergey P.Fediaev storm glass observations. This site is available in either English or its original Russian.
Robert Fitzroy - This is a brief biography of Fitzroy, including a portrait
and references.
Unusual Weather Instruments: Admiral FitzRoy's Crystal Stormglass-
Barometer - You can order a storm glass from this site, which also provides information on the history and use of the storm glass.
Voyage of the Beagle - The Online Literature Library provides Darwin's
book, divided into chapters.

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daAA? nu crezi ca stiam shi eu asta..ca molecula de H e diatomica shi bla bla bla....da' nu am mai scris de lene....EU vroiam sa apun accentul pe practica si aplicatii, nu sa ma leg de scris...get it?

sa revenim

praf de pushca...hmmmm:
KNO3 - se gaseshte la farmacie
insa ai nevoie de S shi C (sulf shi nishte mina de creion)

FORMULA CHIMICA

KNO3+C+S--->K2O + NO2+ CO2 +SO2

trebuie trans din moli in grame pt  a se cunoaste proportzia

PS: folosesc Nenitzescu

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Intr-adevar, astea sunt excelente pentru o gluma reusita ... serveste unui musafir o cafea sau un ceai fierbinte si ajuta-l cu o astfel de lingurita.  

Printre amestecurile de acest fel se numara:

1: Compozitie (procente): 44.7Bi, 22.6Pb, 19.1In, 8.3Sn, 5.3Cd.
Pt = 47°C

2: Compozitie (procente): 49Bi, 21In, 18Pb, 12Sn.
Pt = 58°C

3: Compozitie (procente): 51In, 32.5Bi, 16.5Sn.
Pt = 60°C

4: Compozitie (procente):  50Bi, 26.7Pb, 13.3Sn, 10Cd.
Pt = 70°C

5: Compozitie (procente): 66.3In, 33.7Bi.
Pt = 72°C

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Sure, I got it ... ma intreb insa ce mi-ai fi spus tu daca eu ti-as fi scris in raspuns formule chimice "alandala".

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FORMULA CHIMICA
KNO3+C+S--->K2O + NO2+ CO2 +SO2

Aste e o reactie chimica nu o formula chimica (deosebire importanta) ... praful de pusca e un amestec, deci nu are o formula chimica proprie!

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trebuie trans din moli in grame pt  a se cunoaste proportzia

Proportia difera in functie de scopul pentru care e folosit praful de pusca. Uite aici cateva variante mai cunoscute (procente masice):

KNO3 : S : C = 75 : 9.03 : 15.97

KNO3 : S : C = 88.07 : 7.34 : 4.59

KNO3 : S : C = 74.07 : 9.26 : 16.67

KNO3 : S : C = 73.33 : 8.34 : 18.33

etc.

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Eu mai repede cred ca tu folosesti Nenitescu (Costin D. Nenitescu - Chimie generala / Chimie organica / etc)

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dap....grseala mea....     

Stii cumva cum se poate arde fierul sau lemnul? Ce fel de substante chimice sau combinatii sunt necesare? Formula chimica, denumire ceva?
Iti raman vesnic recunoscatoare daca imi trimiti mesaj, ca nu prea stiu sa utilizez site ul asta. Sunt noua pe aici.
Mersi mult de tot.[SIZE=7][B][COLOR=blue]

....cum se poate arde fierul sau lemnul?  

...  fierul pur arde cu flacara ,  si se aprinde usor ,
...  iar despre ... lemn ....... ??? chiar nu stie nimeni ????