1

Page 1 of almost every Textbook start with the ordinary divison of matter in 2 categories: Substances and Mixtures.
Substances, or Pure Substances sometimes, are defined

as a form of matter that has constant chemical composition and characteristic properties.It cannot be separated into components by physical separation method.

This is according to Wikipedia, at least.

Mixtures always citing wikipedia, instead are

materials made up of two or more different substances which are mixed but are not combined chemically.... Mixtures are one product of a mechanical blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.

Is this separation so radical?
Is there something in between? What about alloys?

Community
  • 1
Gabriele Scarlatti
  • 613
  • 4
  • 14
  • What do you think, can one physically separate an alloy? – andselisk Jan 07 '18 at 20:07
  • related https://chemistry.stackexchange.com/questions/2879/what-is-the-definition-of-of-compound-mixture-element-and-molecule https://chemistry.stackexchange.com/questions/2870/what-is-a-pure-substance – Mithoron Jan 07 '18 at 20:20
  • It can be "divided" only in people's heads. – Mithoron Jan 07 '18 at 20:24
  • Please explain downvotes so that I can try to edit my question., or at least understand what's wrong with it. It would be helpful – Gabriele Scarlatti Jan 07 '18 at 20:39
  • 1
    I don't exactly get what you wanna know. Such categorisations are more or less arbitrary. And your thought about alloys is maybe better then one can think, as there's kinda spectrum between intermetallic compounds and alloys. – Mithoron Jan 07 '18 at 21:48
  • Thank you for your explanation. I'm a beginner I just wanted some clarification or insights on the topic. I would have loved maybe a list of all the "in-between elements" or "border-line" cases, with some explanation :) – Gabriele Scarlatti Jan 07 '18 at 22:47
  • Lists are off-topic - too broad. My thought can be summarised that it is sometimes more or less arbitrary if something is considered chemical compound - "single substance" or mixture of compounds/elements. – Mithoron Jan 07 '18 at 23:30

1 Answers1

-1

Matter....

Matter is generally categorized as either mixtures or pure substances. Pure substances are elements or compounds. Mixtures are either heterogeneous or homogeneous. For heterogeneous mixtures one should be easily able to discern the different components, while if the mixture is homogeneous it appears uniform. Solutions and alloys are homogeneous mixtures.

A concept map which I give to my students: https://c7chemistry.wikispaces.com/file/view/CW%20matter%20concept%20map%20new%20rev%20091211.pdf/300804074/CW%20matter%20concept%20map%20new%20rev%20091211.pdf

Pisgahchemist
  • 27
  • 1