Chemical Definition and 1000 Threads

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. L

    Does the Belousov-Zhabotinsky Reaction Lead to a Steady State or Oscillations?

    I'm interested in oscillating chemical reaction, as Belousov-Zhabotinsky one. Does it oscillate "forever" or it relax to a macroscopical stationary state? Ll.
  2. A

    What does (en) mean in a chemical formula/ligands

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  3. E

    Engineering Chemical Engineering Vs. Electrical Engineering

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  4. C

    Chemical engineering vs chemistry

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  5. L

    Are there any cool chemical reactions i can do in my own home?

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  6. R

    Chemistry The electrical work needed to produce a mole of lead in a chemical reaction

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  7. A

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  8. L

    Engineering Chemical Engineering or Chemistry?

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  9. L

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  11. J

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  12. S

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  13. N

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  14. C

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  15. T

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  16. J

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  17. J

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  18. F

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  19. Q

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  20. N

    Is This the Correct Equation for the Reaction Between Al and KOH?

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  21. L

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  25. C

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  26. A

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  27. D

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  34. D

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  35. E

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  36. M

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  38. D

    Engineering Exploring Careers in Chemical Engineering: Insights from Industry Professionals

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  39. C

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  40. J

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  41. P

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  42. F

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  43. S

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  45. N

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  46. S

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  47. S

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  48. Y

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  49. P

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  50. D

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