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Author Topic: Which chemicals can oxidise copper?  (Read 15864 times)

Offline naglf39

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Which chemicals can oxidise copper?
« on: 11/02/2015 02:21:03 »
which chemicals apply on copper metal it pulls or grain rice.why because rice are  carbo-hydrates {hydrogen carbon} so.In chemical reaction defenetly rice pulls .when rice pulls they change to black.

         And its also fails 2.4 volts torch bulb filament fails when torch focus put  on copper metal then torch filament fails by chemical reaction .

And another one is iron and magnet normally attraction at south to north r north to south poll.At the same time its two repulsion at south  to south r north to north polls.likes it which chemical apply on copper metal its repulsion iron .

And which chemical produce or release high radiation power
« Last Edit: 12/02/2015 11:08:53 by chris »


 

Offline evan_au

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Re: which chemicals apply on copper metal it pulls
« Reply #1 on: 11/02/2015 10:22:32 »
Hi, naglf39, welcome to the forum.
I will attempt to paraphrase the question (apologies if I translate it wrongly):

Quote from: naglf3
a 2.4 volt torch bulb filament fails when the torch focuses on copper metal
It is true that an incandescent light bulb is always working at close to its limits for stress during warmup and cooldown, and the high temperatures of the tungsten filament softens the metal, making it susceptible to mechanical shocks. Any narrowing of the element will cause a high-resistance hot-spot, which is more likely to burn through.

It is conceivable that if a light globe filament were put at the focus of a copper mirror, the reflection would increase the filament temperature, and could make it burn out. But probably the mechanical movement to find the focus, plus normal lamp aging could also contribute to lamp failure.

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then torch filament fails by chemical reaction
If the tungsten filament came in direct physical contact with copper, a chemical reaction could cause filament failure.
However, the torch filament is isolated from the outside world by an inert glass globe, filled with an inert gas.
So copper can't come in physical contact with the filament without breaking the glass globe; if the glass breaks, a chemical reaction with oxygen in the air will cause immediate filament failure, even without touching copper. 

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iron and magnets normally attract, at south to north or north to south pole. At the same time, its repulsive at south to south or north to north poles.
This is a good description of the behavior of two permanent magnets.
However, many iron alloys are ferromagnetic, which means they are attracted to both north and south poles of a magnet.
For "soft" iron alloys, once they are removed from an external magnetic field, they do not retain a strong magnetic field of their own, and so do not attract each other very strongly.

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like copper metal repels iron.
I am not quite sure what this refers to. Perhaps:
You can make an electrical battery by placing copper and iron plates in an electrolyte solution. If the current is high enough, magnetic fields could cause repulsion. But this effect would not be noticeable at normal currents from a copper/iron battery.

If you use a "hard" iron alloy, it can retain a magnetic field, creating a permanent magnet. If you drop a permanent magnet beside a copper plate, the moving magnetic field will induce a current in the copper, slowing down the falling magnet; I guess you could call this "repulsion".  This is a magnetic effect, rather than a chemical effect.
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which chemical produces or releases a high radiation power
A favorite experiment in science class is to burn a magnesium strip in air. This produces a brilliant white light.
Be careful: hold it at far away with tongs, and don't stare at it, or it will hurt your eyes.

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which chemicals apply on copper metal it pulls or grain of rice.
I'm sorry, but I can't translate "pulls". Can you suggest another word instead of "pulls"? Perhaps "reacts"?

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when rice pulls they change to black
I could imagine that if wet rice came in contact with copper, it could react with oxygen or other chemicals in the air to make the copper go black.
 

Offline naglf39

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which chemicals apply on copper metal it attract rice
« Reply #2 on: 11/02/2015 12:13:58 »
 which chemicals apply on copper metal it attract rice .rice are carbohydrates they are in carbon hydrogen.i am aksing anti iron chemicals like magnet with iron repullsion at the same as it is copper iron repulsing on which chemicals reaction.

 what is that chemical raction on copper metal tell me

its para magnetism. what it does is it attracts hydrogen thats why it attracts  rice. rice is made of hydro carbons. when it pulls it makes rice go black(brownish). it pulls all hydrogen and leaves carbon behind. carbon is black(brownish).

i dont want physical reaction which chemicals using on copper metal then result is that tell me sir


at the same time i am asking which chemicals using on copper metal it releases heat r radition then it shows reaction  on torch light focus then some seconds torch filament failed i saw already  but i dont know what is that chemicals so please tell me chemicals i dnt want physical reactions.

at the same time i want copper absorption chemical,when i apply some chemical on chemical then copper absorb that any chemical instant so what i will do tell me sir
 

Offline evan_au

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Re: which chemicals apply on copper metal it pulls
« Reply #3 on: 11/02/2015 21:13:55 »
One way to see which chemical reactions might occur, you can look at a table of chemical bond energies. (There are more complex considerations like activation energy, but don't worry about that here...)

Quote from: paraphrase
rice is made of hydrocarbons. When [copper] pulls [a hydrogen off the hydrocarbon] it makes the rice go black(brownish). It pulls off all hydrogen and leaves carbon behind. carbon is black(brownish).

The hypothesis here is that copper metal attracts the hydrogen atom so strongly that it pulls the hydrogen atoms off the rice's carbon backbone, leaving atomic carbon, which produces a black color.

By looking up a table of bond energies, you can find the energy required to break bonds between the metal copper atoms, and between Hydrogen and Carbon (or Hydrogen and Oxygen), and then re-form bonds between copper and hydrogen. The reaction will proceed more rapidly if energy is released by the chemical reaction. Due to the large number of possible chemical reactions, such tables are large

I think you will find that chemical reactions between copper and hydrogen are not as favored as between Carbon and Hydrogen or Oxygen & Hydrogen.

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rice are carbohydrates they are made of carbon and hydrogen
This is partially right; carbohydrates are mainly made of Carbon, Hydrogen and Oxygen. If you removed the Hydrogen, you would form a lot of carbon dioxide, which is a colorless gas, plus some carbon black.

An alternative hypothesis is that wet rice in contact with the copper encourages the reaction of Oxygen in the air with Copper metal, forming copper oxide CuO, which is black or dark brown. The rice would not participate in this reaction (although bacteria would happily break down the rice).
 
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its paramagnetism. What it does is copper attracts hydrogen. That's why copper attracts  rice
Formation of chemical bonds can occur through a variety of mechanisms.

Covalent bonds occur in hydrocarbons: an outer electron from one atom (eg Oxygen) pairs with an outer electron from another atom (eg Hydrogen). This can be seen as a magnetic attraction between two electrons on a subatomic scale.  This electron pairing effect is much stronger than paramagnetic effects that can be seen on the scale of a rice grain.

An alternative hypothesis is that the surface tension of wet rice grains, plus starchy glue from boiling makes the rice grains stick to a copper sheet.
 

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Re: which chemicals apply on copper metal it pulls
« Reply #3 on: 11/02/2015 21:13:55 »

 

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