Microwave heating

Discussion in 'Chemistry' started by arauca, Jun 17, 2013.

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  1. exchemist Valued Senior Member

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    Aqueous Id has explained what Hydrogen Bonds are. In the case of water their enthalpy of formation is about 20kJ/mole. By comparison the covalent O-H bond in water has an enthalpy ~ 450kJ/mol, so around 20 times stronger.

    More generally, light in the UV, visible and occasionally IR regions can be strong enough to break chemical bonds, which is the basis of photochemistry: https://en.wikipedia.org/wiki/Photochemistry

    Usually this involves the formation of free radicals rather than than ions.

    The energy needed to break bonds is generally quite a bit less than that needed to detach a free electron, because in photochemical bond-breaking all the electrons end up in bound states.

    But indeed microwaves do not have the energy to do this.

    Actually it is interesting that the Hydrogen Bond is what gives water its anomalously high specific heat capacity: the H bonds provide another series of energy levels to populate, in addition to the higher rotational and internal vibrational energy levels.
     
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  3. Layman Totally Internally Reflected Valued Senior Member

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    Microwaves will not always create a chemical reaction, but they will create a chemical reaction with certain types of materials. Some things you stick in there will catch on fire and begin to spark immediately. Electromagnetic radiation is only known to cause a chemical reaction, mostly because it increases the heat of the object to a temperature that would then be sufficient to cause a chemical reaction on its own. So then the fact that certain types of materials can spontaneously spark a chemical reaction inside of a microwave seems to be a bit of an enigma.

    On another note, radar is a high power device that uses high voltages in order to create a signal that would be hundreds of volts that then creates so called "walls of death", it has a similar transmission system to the microwave oven. It was said that in order for them to transmit electrons that it would require high voltages, but that thread was closed so I didn't get a chance to mention that they are high voltage devices when it was said that it would be required in order for them to transmit electrons.

    But, since you know that they do not transmit electrons maybe you could make up some theory to explain why microwaves would spontaneously create a chemical reaction (catch on fire almost immediately changing the formation of chemical compounds) from electromagnetic energy or continue to deny that certain materials will catch on fire spontaneously in a microwave oven that would then be considered a chemical reaction.
     
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  5. AlexG Like nailing Jello to a tree Valued Senior Member

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    Still trying in vain to remember your 1960 radar tech manual?
     
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  7. Layman Totally Internally Reflected Valued Senior Member

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    Well in the Navy electronics school the entire course is based off of tech manuals that date back to even the 1950's, these where like the text books that they used for obtaining an associates in electronics.

    This doesn't change the fact that radars are high voltage systems. They wouldn't make them require high voltages for no reason, there is unsaid rule for efficiency in electronic design. You wouldn't manufacture a device that uses high voltages when it was not necessary.

    I think that is more reliable source than you any day, and I fully remember these aspects of the descriptions in it. It was repeated many times because it was a safety issue. You can actually die from sticking your hands in the wrong places of one that has these high voltages. I don't think you are even justified in saying that is half remembered when you didn't even have a minor inkling of this type of detail, therefore you couldn't possibly have known more information about it than I do.
     
  8. AlexG Like nailing Jello to a tree Valued Senior Member

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    Except it doesn't transmit electrons, it transmits photons, as has been pointed out to you time and again, with references and cites.
     
  9. billvon Valued Senior Member

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    Microwaves don't transmit electrons. The reason they use high voltages is that the magnetron, the device of choice for producing microwaves, works best at high voltages.

    Because microwaves make things hot. They then catch on fire.
     
  10. Layman Totally Internally Reflected Valued Senior Member

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    Then this leaves open a lot of unanswered questions.

    How does electromagnetic energy spontaneously create a chemical reaction in the microwave range but not in other ranges when it was only attributed to the heat it causes?

    Why is it required that they are high voltage systems? When electromagnetic energy doesn't require high voltages.

    Why do they teach that electron beams can be given names from the electromagnetic spectrum, and would be know everything internet "scientist" deny the form of use of these terms?

    Why do we not know how the Higgs Boson can emit photons when according to quantum theory it should not be able to and it was supposed to inform us what is currently wrong with quantum physics?

    The Higgs Boson is undeniable proof that we do not even know what photons can and cannot come from, this blatant error is a slap to the face to theoretical physics. To pretend otherwise would be to absolutely deny any findings of the LHC that is the pinnacle of scientific experiment today. To accept that they did find a Higgs-Like Boson in the LHC from two photons would mean having to accept that we do not even know where photons can and should even come from.

    The problem I see here is that theoretical physicist have just denied facts about electronic theory and has brushed it aside as bad memories and have changed the facts to fit their inaccurate theory that does not comply with the "experiment" that is modern technology and its descriptions.

    I HAVE HAD INSTRUCTORS SAY THAT ELECTRON WAVES IN ELECTRONICS CAN BE GIVEN NAMES FROM THE ELECTROMAGNETIC SPECTRUM AND I CLEARLY REMEMBER THESE STATEMENTS!

    Obviously not, if people would then assume that they could only actually be electromagnetic waves and then corrupt information because of it.

    Then there are a few possible roads this can take, they can either introduce a new particle that does absolutely nothing but show that we do know where photons can possibly come from, or we could admit that we do not know where photons can possibly come from, and we could try to describe the Higgs-Like Boson with Newtonian physics as a simple collision between the W and Z boson.

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    Only one of these roads will keep from allowing quantum theory to keep certain aspects of electronic theory in the dark, and this may continue for the rest of time since once they make up their minds they will assume to know everything by accepting these things as facts no matter what. I think one thing is for sure here, you cannot know quantum theory and then pretend to know something about electronics. That should be the lesson learned from the Higgs Boson.
     
  11. Read-Only Valued Senior Member

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    I have to agree with this, Layman, simply because it's correct - radar does NOT "transmit electrons." The very thought of that is absurd!

    In fact, despite your training - which obviously did not ALL sink into your brain - much of what else you've said is also incorrect. I worked with microwave equipment for decades and that included the klystron and magnetrons that generated microwaves as well as a specialized amplifier called a "traveling wave amplifier tube" (yes, we insiders in the industry actually called them by their acronym, TWAT) in some specific applications. And your claim of "high voltage" is far, far out of date. Do you actually think those speed detection devices used by law enforcements employ hundreds of thousands of volts? For shame!

    I was also there when Raytheon's commercial products division, Amana, hit the market with it's first domestic microwave oven - which it labeled "Radar Range" in 1967. (They had previously sold a larger, pricier, institutional version dating back into the mid-1950s.)

    As you can see, I know and was involved in the history as well as you were. However, you're making the MAJOR mistake of attempting to sell your version of history as if it were the modern "gospel." Things have changed considerably since your heyday (which you also remember imperfectly). One example being that solid-state microwave generators were introduced over 30 years ago and operate in the same voltage ranges as today's laptop/desktop computers.

    Hopefully, you will choose to take about a year to bring yourself up-to-date before trying again to present yourself here as an expert - especially since there are some present that know considerably more about the topic than you do.
     
  12. Layman Totally Internally Reflected Valued Senior Member

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    The reason I was given that it could not be electrons is that a cathode would only send electrons if it was at a high voltage. It is the same way that they would create a cathode ray or electron beam. A piece of metal would be at a high voltage. It really isn't as absurd as you think it would be, the electron was discovered from a cathode tube, that is a piece of metal of high voltage in a glass tube.

    No I don't, I think they use lasers. I don't think a laser would consist of electrons. Then it does not us a high voltage, go figure.

    One of the first forms of wireless communication was a microwave transceiver that I think would go back to the early 20th century. 30 years ago would have been in the 80's. You have just shown me that you actually do not know about when these technologies where first introduced.

    The thing is that they don't. They just think that since they know things about quantum theory that automatically gives them some sort of insight into the operations of electronic devices. So then I have shown that quantum theory actually hasn't been shown to be accurate in this regard, if it was they wouldn't be wondering why photons are given off by a Higgs Boson. It shouldn't be allowed by quantum theory. Where else could they have gone wrong assuming where photons can and cannot come from?
     
  13. AlexG Like nailing Jello to a tree Valued Senior Member

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    No, they are radar units, running on 6 AA batteries.

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  14. Layman Totally Internally Reflected Valued Senior Member

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    Oh please, you are just compounding your own ignorance based on not knowing how these devices work either. I know for a fact that the first speed detection used lasers, you could even see a red light coming from them. This discussion is utterly hopeless. Why don't you go learn how they actually transmit a signal. I don't think they could possibly use the same method because then they wouldn't be able to compare a difference in frequency because then they would only accept one kind of frequency.

    A laser is created by exciting a gas with an electrical signal. That would then convert it to the electromagnetic spectrum. The light is then reflected at multiple frequencies in a chamber. It is like a neon light. It is the same they would do to detect electrons, they saw that if a gas was present then it would convert into light and then the electrons are detected from those light rays.
     
  15. Layman Totally Internally Reflected Valued Senior Member

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    I could stick a fork in it. Then I would notice that it is sparking with flames, and then reach in immediately and grab it. Then I would not get burned after it has only been in there for a few seconds. It wouldn't have to come even close to a temperature that would be required to create a chemical reaction from that metal by any other means. It would seem as though this type of event would defy all known laws of physics and chemistry.
     
  16. Read-Only Valued Senior Member

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    You're either a liar or an absolute know-nothing crank! I'd bet my money on the latter.The first speed detection device the cops used were RADAR - lasers came much later. Why not do yourself a favor and simply research it?

    Nothing else you said was valid either. And the 1980's is absolutely correct about solid state microwave generators. Look that up also, unless you are afraid to!
     
  17. billvon Valued Senior Member

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    Because microwave ovens heat materials very differently than convection or thermal radiation ovens. Thus you would expect reactions to differ.

    It's not. If you generated microwaves with low voltage PA's you'd get the same results.

    Because both photons and moving electrons have energies.

    Ancient radar technology is a poor basis on which to dispute modern physics.

    HeNe and argon lasers operate at very high voltages. Semiconductor lasers operate at low voltages. Chemical lasers use no voltages at all. Google it for more information.

    Such devices use infrared lasers, not visible ones (for obvious reasons.) Compounding your own ignorance indeed.
     
  18. AlexG Like nailing Jello to a tree Valued Senior Member

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    Layman is pretty hopeless. He's certain he's right and the rest of the world is wrong. He clings to that even in the face of overwhelming evidence.
     
  19. Read-Only Valued Senior Member

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    Indeed. Even when someone with heavy experience in a field provides him with information that he could easily verify is correct. That proves him to be a sad and worthless individual when speaking in a public forum.
     
  20. Layman Totally Internally Reflected Valued Senior Member

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    Why don't you try 1880, you seem to be one hundred years off. Invention of radio

    "After Maxwell's theory was published many people experimented with wireless communication, some intentionally using Maxwell's theory some not. It is considered likely that the first intentional transmission of a signal by means of electromagnetic waves was performed by David Edward Hughes around 1880, although this was considered to be induction at the time. The first systematic and unequivocal transmission of EM waves was performed by Heinrich Rudolf Hertz and described in papers published in 1887 and 1890. Hertz famously considered these results as being of little practical value."

    The first radios used the microwave band but they did away with it because it started microwaving stuff. Electronics no longer transmit in the microwave band.

    Microwave Transceiver means a 2 way radio that operates in the microwave band of frequencies. The idea that this was invented in 1980, 30 years after the microwave oven is laughable when they would have been made obsolete after the 1950's where then they only used Radio Transceivers or just 2 way radios.
     
  21. AlexG Like nailing Jello to a tree Valued Senior Member

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    He wasn't talking about the invention of radio, he was talking about solid state microwave generators.

    No, the first radios used the radio band.

    Here's the electromagnetic spectrum. IT'S ALL PHOTONS.

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  22. arauca Banned Banned

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    Are there MANY KINDS of Photons ?
     
  23. AlexG Like nailing Jello to a tree Valued Senior Member

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    There's only 1 kind of photon, but it can have many different frequencies and energy.
     
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