when were the distinctions between chemical and physical changes formed? date, month, year...?
970747
As to what?  The very first time or a specific chemical / physical entity?
1029590
The history of chemistry may be said to begin with the distinction of chemistry from alchemy by Robert Boyle in his work The Sceptical Chymist (1661). Both alchemy and chemistry are concerned with the nature of matter and its transformations but, in contrast with alchemists, chemists apply the scientific method. The history of chemistry is intertwined with the history of thermodynamics, especially through the work of Willard Gibbs.\n\n\n\nOrigins\n\nAlthough the archives of chemical research draw upon work from ancient Babylon, Egypt, and especially Persia after Islam, the birth of chemistry is often dated to Antoine Lavoisier's discovery of the law of conservation of mass, and thereby to his refutation of the phlogiston theory of combustion in 1783. (Phlogiston was supposed to be an imponderable substance liberated by flammable materials in burning.) Mikhail Lomonosov independently established a tradition of chemistry in Russia in the 18th century. Lomonosov also rejected the phlogiston theory, and anticipated the kinetic theory of gases. He regarded heat as a form of motion, and stated the idea of conservation of matter.\n\nThe vitalism debate and organic chemistry\n\nAfter the nature of combustion (see oxygen) was settled, another dispute, about vitalism and the essential distinction between organic and inorganic substances, was revolutionized by Friedrich Wöhler's accidental synthesis of urea from inorganic substances in 1828. Never before had an organic compound been synthesized from inorganic material. This opened a new research field in chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds. The most important among them are mauve, magenta, and other synthetic dyes, as well as the widely used drug aspirin. The discovery also contributed greatly to the theory of isomerism
148193
A physical change would include changes that have to do with the physical aspects of the substance, such as: color, state of matter, or temperature. A chemical change occurs when a reaction takes place and a new substance is produced, like the reaction of sodium and chlorine to produce salt.
58587
A chemical reaction is a process that results in the interconversion of chemical substances. The substance(s) initially involved in a chemical reaction are called reactants. Chemical reactions are characterized by a chemical change and it yields one or more product(s) which are different from the reactants.
870205
Er, that's hard to explain... a chemical property of a substance is how it would react with other substances. For example, a chemical property of an acid is that it would react with alkali to form salt and water. While a physical property of an acid is that it is corrosive.
208346
Strictly speaking, a chemical change occurs when the bonds between atoms are either made or broken (often both).  Bonds can be either covalent (electrons are shared), ionic (one or more electrons are given up by one or more atoms and given to another atom or atoms), or metallic.  Burning something is a chemical reaction.
930639
Well it's definitely not a physical change. Not by definition anyway.\nWhat was once food is very chemically altered after going through the digestion process...so YES.
329767
You might be looking for information on alchemy, not chemistry.  The two fields of study are very seperate these days.  Of course, modern scientits could turn lead into gold by nuclear fusion, or turn heavier elements into gold by fission- neither process seems practical.
810776
Physical properties are those which entail the actual physics structure of matter, while chemical properties are those which cocern the chemical makeup of matter.
293050
Are you refering to Physical Responses, or Interation of mass structure?Nuclear reaction,chemical reaction...etc..
252753
Changes that don't involve chemical reaction. Example: chenge in state (solid, liquid, gas), temperature change, etc. Ofcourse temperature change will initiate density change.. density is another physical property.
733335
Yes it is a chemical reaction, aka  chemical change. Carbon dioxide and water are combined with light energy to form glucose( a type of sugar ) and oxygen.  You end up with different substances than you begin with, therefore it's a chemical change
856617
this is the  answer for the two, the others, you can ask to this site\nhttp://www.answers.com/\n\nhttp://cm.bell-labs.com/cm/ms/departments/sia/jmc/pub.html\n\nhttp://www.answers.com/research%20journal%20of%20Chang%20S%20H
915926
just cutting the hair is a physical change\n\ndyeing the hair is a chemical change\n\nhope this helps!
764428
For chemical changes, the energy scale is related to Boltzmann's constant, which is pretty small, and temperature, which is typically 1-1000 degrees.  For nuclear changes the energy scale is related to Einstein's famous equation, E=mC^2.  the mass is typically very small, say the mass of an electron, but the speed of light is huge, and gets squared, making nuclear changes much, much more energetic than chemical changes.  That's why the sun is billions of degrees, and a campfire is only thousands of degrees.
993791
: a science that deals with the composition, structure, and properties of substances and with the transformations that they undergo\n2 a : the composition and chemical properties of a substance <the chemistry of iron> b : chemical processes and phenomena (as of an organism) <blood chemistry>\n3 : a strong mutual attraction, attachment, or sympathy <they have a special chemistry>
751958
heat change\ncolor change\nemmission of gas