What is Chemical: Definition and 1000 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. H

    Engineering Chemical Engineering vs. Electrical Engineering

    Hello, I am very new to the forums, and I ran across another form discussing these two topics; however the previous thread was mainly discussing nanotechnology. I am interested to find out which carrier I should pursue: chemical eng. or Elec. Eng.? I am extremely interested in both...
  2. K

    Request for a book: Chemical Thermodynamic by Peter Rock A.

    Hello! Does anyone have a free ebook of Chemical Thermodynamic by Peter Rock A.?
  3. S

    Balancing Chemical Equations with Linear Algebra

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  4. L

    Chemical Nomenclature: Learn Names, Formulas & More

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  5. K

    Chemical Equilibrium with individual reactions

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  6. M

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  7. P

    Chemical Potential Energy and Kinetic Energy

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  8. J

    Engineering Biochemistry vs. Chemical Engineering

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  9. H

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  10. Pythagorean

    What are the fundamental forces involved in the chemical reaction?

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  11. C

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  13. M

    Calculating chemical potenntial

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  14. S

    Chemical kinetics/heat equation

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  15. M

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  16. S

    Chemical composition of solar system

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  17. X

    How Does Pressure and Temperature Affect the Chemical Potential of CH4?

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  21. H

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  22. C

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  24. I

    Products of a chemical reaction

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  25. D

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  30. I

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  31. P

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  32. H

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  33. E

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  34. P

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  35. G

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  36. H

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  44. A

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  45. R

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  46. C

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  47. D

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  48. L

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  49. A

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  50. E

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