What is Chemicals: Definition and 79 Discussions

A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be simple substances, chemical compounds, or alloys. Chemical elements may or may not be included in the definition, depending on expert viewpoint.Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical.
Chemical substances exist as solids, liquids, gases, or plasma, and may change between these phases of matter with changes in temperature or pressure and time. Chemical substances may be combined or converted to others by means of chemical reactions.
Forms of energy, such as light and heat, are not matter, and are thus not "substances" in this regard.

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  1. K

    Common chemicals released under sunlight exposure?

    What are the common and/or possible chemicals that could release from clothes or bedclothes when it is exposed to sunlight? Since there are many different textures and additives so I am concerned about the common chemicals that could release I roughly know that sunlight will break a lot of...
  2. K

    Could our body deal with trace amounts of unknown chemicals?

    Even if how careful we are, I think it is hard for us to avoid TRACE amount of unknown chemicals that get into our body unconsciously, through different pathway, our mouth, our nose and our eyes or our wound. Could our body handle these foreign chemicals in trace amount and keep us healthy? Does...
  3. K

    Can Customs X-Rays Detect Toxic Chemicals?

    Could customs x-ray security check find out if there is trace of toxic chemical left in the product? I do NOT mean illegal drug because it is supposed to be found out, but how about if there is any trace of other toxic chemicals? Could it be found out?
  4. J

    Removing green copper oxides with Electrolysis, chemicals, etc.

    I soaked the following school medallion in water with salt for 20 plus years in the attic and at that time I didn't know copper could corrode and make green oxides. I also didn't think about it much and just forgot about it. I brought it down just today. I read just a while ago that hot...
  5. dcybroz

    What materials are the most resistant to chemicals?

    Ok so I am building a fume hood What materials are the most resistant to chemicals that are also cheap? also what cfm fan can I use to suck out the air? (asking for someone knowlageable) cats
  6. kelvin490

    Easy way to make carbonic acid from other chemicals

    Hi, everyone. I would like to test for the reaction between carbonic acid and copper (to simulate the effect of acid rain on copper). However, I find that many supplies failed to provide carbonic acid (either in powder or liquid form). Some says that carbonic acid is unstable and thus cannot...
  7. I

    Chemicals coded to leave a cell and then come back?

    Is there such a thing of a protein (or some other biochemical) being coded to leave the cell, do something (or not) and then return for another function in the cell? Or in some way go "in and out" throughout its existence? Or at the least that would "take a leave of absence" and then become...
  8. G

    I What chemicals inside a hearing aid battery make it explode?

    I saved 75 used hearing aid batteries and threw them into a fire. It took about 8 seconds then, boom, boom, boom, boom, boom, boom, boom, boom, boom, boom, boom, boom, boom, boom, boom,boom, boom, boom, boom, boom, boom, boom, boom, boom, boom,boom, boom, boom, boom, boom, boom, boom, boom...
  9. D

    NurdRage finally got Pyrimethamine from household chemicals

    I wanted to bring to your attention what I think this is one of the most ambitious chemistry projects to be found on youtube: A guy with the pseudonym of NurdRage or Dr. Butyllithium tried to synthesise a medication called Pyrimethamine or Daraprim which is effective against Toxoplasmosis from...
  10. N

    How should I contain my KNO3?

    I just got 2lbs of 99.8% Pure KNO3 Powder in the mail. It came in a kind of sketchy bag. I want to contain somewhere safe, so... where should I put it? Is an old Pretzel Snack plastic container good enough, or do I need a good seal?
  11. L

    To oxidate HF to F2 with chemicals only

    Is it possible to oxidate HF to F2 putting HF in contact with oxidizing compounds only, that is, without using electrolytic cells or, however, electric energy in general? Thank you. -- lightarrow
  12. I

    Do exactly the same chemicals react with each other

    Not sure if this is well know but for some reason, I don't know if exactly same chemicals make chemical reactions with one another and if yes, how common that is?
  13. B

    What if a chemical reagent reports purity as a range?

    I have a chemical reagent that says: Assay ... 93.0 ~ 103.0% Which value should I use in theoretical computations? Should I take the average or the lowest value? Thanks!
  14. D

    Strange question:which chemicals cause skin reactions

    A little complicated and interesting story, I will get down to the point: I need a number of substances that cause skin rashes/skin redness or overall has a bad reaction to human skin. This is all for research purposes for natural skin products me and a group of friends are developing.
  15. T

    Absorbed chemicals in contact lenses?

    Dear scientists, I had stupidly put a few boxes of Acuvue Moist Contact lenses together with a plastic bottle of "extra mild dissolvant" (nail polish remover) these stayed in the same bag in a closed cupboard for months before I noticed it. The dissolvant contains Ethyl Acetate, Butyl...
  16. wolram

    Excess of chemicals found US water

    Seems like the US is having a raw deal, have you checked your water is safe to drink? https://www.sciencedaily.com/videos/0233de5148b63e6e2bd95b0fcb0daca8.htm
  17. Klacid

    How do i make chemicals by equation?

    Hey guys i wanted to know how make some chemicals when i have an equation, for example:
  18. N

    Chemicals with a strong smell

    Hi there Do you all have any chemicals that you can think of in a laboratory that give off a very strong smell and should be used under the chemhood I just used Glacial Acetic Acid today and I had no idea how strong the smell was . from now on I am using it under the chemhood I have created a...
  19. E

    Science Fair Project: Natural Water vs Bottled

    Hello I'am a high school student doing a science fair project on the chemicals and heavy metals found in both natural water sources(lakes,rivers,streams) and bottled. I'am looking to see if anyone has information like a list of chemicals and heavy metals found in both sources. any reply is...
  20. S

    Are there any interactions from mixing these chemicals?

    Hi, So I recently got a new job, and when I was being instructed on how to close my department, I noticed that they used quite a bit of chemicals on the same surface (it's a salad bar). I was wondering if any of these chemicals could interact, and if so, what the products would be. First, the...
  21. MenkeBenjammin

    What chemicals will take up dissolved oxygen?

    I am developing a model of dissolved oxygen (DO) consumption by yeast in the fermentation process. I would like to use a solution that will predictably take up DO over the course of 1 or 2 hours so that I can test a more basic model with the laboratory equipment I have. This would prove I have...
  22. N

    Chemicals in tigerbalm and pvc figures?

    Hi, I'm new here :) I recently moved in with a new roommate who seems to use tigerbalm quite frequently he said its help elevate his allergy but I have some collections of both vintage and new star wars figures and miniatures I'm wondering whether vapour of chemical from Tigerbalm and or grease...
  23. S

    Simple test for harmful chemicals in food

    What are the different ways to detect harmful chemicals in food? I need to find at least 5 tests for different chemicals for my chemistry investigatory for my final exams. I have only chemicals available in a standard lab in my hand.
  24. aroc91

    Best place to sell surplus chemicals?

    Hi all. I recently came into the possession of a fair amount of various chemicals in various amounts. It's not anything outrageous (mostly a lot of ionic silver and lutetium compounds), so eBay would accept it, but I was just wondering if there was a better alternative.
  25. thankz

    Where do you buy your chemicals from?

    what should the price of this be?
  26. S

    What chemicals all labs should have?

    If the question doesn't make sense how 'bout this one: "What chemicals should an amateur chemistry lab should have for experimentation?"
  27. Y

    Does toothpaste chemicals may be damage to our health?

    Note: My english isn't well. Everyone knows toothpaste's has chemicals in variety. Floride is the main chemical. But how do you know if its not harm your health in the future? May be it cause cancer in the future. So what precautions do you take when you brush your teeths? How long have you...
  28. D

    Making an explosive volcano without chemicals? HELP

    Making an explosive volcano without chemicals? HELP! So here's the deal. I have to make a volcano that does not use chemicals or substances (potassium nitrate, baking soda, vinegar). It has to use mechanical parts to symbolize a volcanic eruption (ie springs for pressure). Any ideas? I have...
  29. B

    Help identifying unknown chemicals.

    I have 9 white solids which i need to identify. Aluminium ocide (Al2O3), Calcium Oxide (CaO), Sodium dithionite (Na2S2O4), aluminium sulphate ( Al2(SO4)3 ), Ammonium sulphate (NH4)2SO4, calcium nitrate ( Ca(NO3)2 ), Magnesium sulphate (MgSO4), sodium carbonate (Na2CO3), Sodium thiosulphate...
  30. skyshrimp

    Where's the best place to buy chemicals?

    I'm just a hobbyist learning basic chemistry for fun home projects. The first thing I'd like to try out is the Chloride test which requires potassium chromate and silver nitrate. I'll only need less than 50g of each compound. Where's the cheapest place in the UK to buy this stuff? 50g of...
  31. I

    What chemicals will dissolve biological matter fastest?

    In the matter of 30 seconds, preferably. So far it seems Sulfuric Acid, Hydrogen Peroxide and Permanganate in a cocktail will suffice. Are there any faster, cheaper methods? Thanks :)
  32. J

    Chemicals With Chlorinated Solvents

    I am taking the OSHA 30 course as a requirement of a job and came across some information regarding the danger of welding on materials that have had chlorinated solvents applied. Being someone who manages industrial construction projects, but often doesn't supervise welding operations, I am not...
  33. S

    Solidifying Powders: What Chemicals are Needed?

    Hello, how could I make a powder became solid ? Do I need some chemical that can solidify it ? thank you
  34. T

    What Chemical Can Effectively Trap Odours in Cat Litter?

    Hi, I was wondering if anyone knew of a chemical that trap odour? The idea is to design cat-litter using perlite as the main ingredient however; as perlite doesn't have 'odour-trapping' properties I was hoping to mix it with another chemical... Thanks...
  35. S

    Chemicals that can dissolve or react with carbon particles and alloys like steel

    is there any acid or base or any other chemical which can dissolve carbon particles or tar but will not effect alloys like steel.
  36. P

    Unveiling the Colour Secrets of Chemicals: Understanding CuSO4 and PbI Hue

    I know that CuSO4 is blue or PbI is yellow. Is there any way to remember the colour of all chemicals?
  37. L

    How can i dispose of chemicals safely

    I have recently gotten fascinated with chemistry, and I am looking to start it as a hobby. However one, of the things I want to have under control before i start is chemical disposal. Does anyone know a good cheap company I can hire for hazardous materials disposal? I have heard from a printer...
  38. J

    What all factors decide which chemicals to use?

    I was studying what kind of chemicals are used in various processes like thermite welding , rocket propellant. On what basis are these chemicals used? In welding Al + Fe2O3 is used. Why not Sodium and some weaker oxide as sodium is an alkali metal and highly reactive In rocket propeller H2O2...
  39. A

    Chemicals that freeze at less than 60 Kelvin

    Does anyone know of a reference to a list of all known chemicals that freeze at less than 50 K? I know lots of organic molecules do, but I don't know which ones. I also can find the freezing points of all the elements pretty easy, but chemicals are proving more elusive.
  40. M

    What is the outcome of mixing these two chemicals

    At work we use; Powder Bleach, ACTIVE INGREDIENT: Sodium Dochloroisocyanurate and A cleaning agent, ACTIVE INGREDIENT: Sodium Dodecylbenzene sulfonate These two chemicals are to be used separately but we have the sudden rumour that when mixed in a mop bucket it is significantly more...
  41. C

    Fortran Fortran: separate acids from a list of chemicals in a text file

    Dear Fellow Members, I am presently trying to write a Fortran 95 program to separate acids from a list of chemicals in a text file and then write them to a second text file. The program first matches the word "acid" and is then supposed to check if the word preceding the word...
  42. H

    Question regarding energy from chemicals (M.C.Q)

    Q. A volume of 100 cm3 of 1 mol dm3 sodium hydroxide solution was added to 100 cm3 of 1 mol dm3 hydrochloric acid.The maximum rise in temperature recorded was T1.The experiment was repeated with 50cm3 of each solution and the rise in temperature this time was T2. It is found That A) T1 Is...
  43. C

    Does anyone know which, if any, liquids or chemicals absorb infrared

    Does anyone know which, if any, liquids or chemicals absorb infrared light but not visible light? In other words, something that looks clear but appears dark or black when viewed in infrared. Help is greatly appreciated!
  44. N

    Why are some chemicals more reactive?

    So in high school we learned that chemicals with very few valence electrons want to get rid of them so that they can have a full outer shell, or if they only need a few more to get a full outer shell then the desperately try and get them. The teacher made an analogy that the atom really wants to...
  45. S

    Hydrogen Gas Remediation: Chemicals Available

    Are there any commercially available chemicals that can assist in Hydrogen Gas remediation? Thanks.
  46. 7

    Exothermic Reaction Materials: 180-190 C, Safe & Easy to Acquire

    Not getting any responses in the Chemical Engineering so I'll try here :) Hi all, I'm looking for two material to produce an exothermic reaction of 180-190 C. I'd prefer the materials to be cheap in larger quantities (think mass production, not mass explosion :smile:). Safe, other than...
  47. T

    Chemicals that glow with specifics colors when exposed to an current

    I'm looking for certain chemicals that glow with specifics colors when exposed to an electric current.
  48. M

    Keeping moisture-sensitive chemicals dry

    For a while, I've been stepping outside my comfort zone a bit and working with really moisture-sensitive chemicals (isothiocyanates, carbodiimides, succinimides, etc.: stuff that rapidly hydrolyzes and loses functionality). Even though we only purchased a tiny amount each time, we only used a...
  49. P

    Oxidation of Organic Chemicals

    In the oxidation of organic chemicals, are there any conditions that must involve water or must not be in the presence of water or the oxidation process will stop despite the presence of the oxidizing agent? I remember my teacher saying something about this, but I don't remember which one it is...
  50. N

    Can I mix these 3 chemicals together?

    Can I mix these 3 chemicals together?? I'm not a chemist so don't laugh at my lack of knowledge: I want to mix pure Benzene, Toluene and Cyclohexane into a single Cuvette. Is this alright? I'm not going to produce any harmful gases or weapons of mass destruction? Thanks.