2.3+Kinds+of+matter

Material
"Japanese physicists claim to have found evidence of 'strange matter' in cosmic rays. Their detectors have recorded two separate events, each of which can be explained by the arrival of a particle with a charge 14 times as great as the charge on a proton, and a mass 170 times the proton's mass. No atomic nucleus -- made of protons and neutrons -- exists that matches this description, but these properties are precisely in the range predicted for so-called quark nuggets, which physicists believe may be made of a type of material dubbed strange matter." //taken from:http://www.science-frontiers.com/sf073/sf073a02.htm //

//taken from:http://www.dailygalaxy.com/.a/6a00d8341bf7f753ef012876721ca1970c-320wi //

Some objects are made of material that seems to have a consistent compositon throughout. This might be a metal, glass, marble, plastic, paper, etc. Such material is referred to as "homogeneous". If the material obviously varies from one region to another, as seen in travertine, wood grains, particle board, are called "heterogeneous". The composition varies throughout a heterogenous material. Rocks can be homogeneous as is the case of fine-gained igneous rocks such as obsidion or heterogeneous as in the coarse-grained igneous rocks such as granite. Clear solutions are homogenous mixtures as is the air.

Substances
A "substance" has a rather definte chemical composition. As such a substance is homogeneous. A salt solution is homogeneous but is not a substance because the chemical composition is quite arbitrary. It can range from very dilute to concentrated and still be a homogeneous material. A substance usually refers to materials such as salt, sugar, water, calcite, quartz, potassium chloride, all of which have definte ratios of their component elements. Nitrogen is a substance, air is not. Zinc or zinc oxide are sustances, bronze and brass are not. Ethanol is a substance, wine is not. Wine can have a wide range of compositions, ethanol contains definite ratios of carbon, hydrogen and oxygen combined in a certain way. A glass of water with ice-cubes is heterogeneous in that there different "phases" that have distinct boundaries and interfaces yet there is a single substance there (water). The ice is a solid phase, the water is a liquid phase.



[]​


 * Kinds of Matter **

Chemistry is defined as the study of matter. In this introductory text we will not study all types of matter. Rather, we will concentrate on simple substances, the properties that identify them, and the changes they undergo.

**Pure Substances **   A pure substance consists of a single kind of matter. It always has the same composition and the same set of properties. For example, baking soda is a single kind of matter, known chemically as sodium hydrogen carbonate.


 * [[image:http://genchem.chem.wisc.edu/sstutorial/Text1/Tx12/NaHCO3.gif width="200" height="98" align="center"]]

|| A sample of pure baking soda, regardless of its source or size, will be a white solid containing 57.1% sodium, 1.2% hydrogen, 14.3% carbon, and 27.4% oxygen. The sample will dissolve in water. When heated to 270°C the sample will decompose, giving off carbon dioxide and water vapor and leaving a residue of sodium carbonate. Thus, by definition, baking soda is a pure substance because it has a constant composition and a unique set of properties, some of which we have listed. The properties we have described hold true for any sample of baking soda. These properties are the kinds in which we are interested.
 * Baking Soda ||

A note about the term //pure //; in this text, the word //pure // means a single substance, not a mixture of substances. As used by the U.S. Food and Drug Administration (USFDA), the term //pure //<span style="font-family: Arial,Helvetica,sans-serif;"> means "fit for human consumption." Milk, whether whole, 2% fat, or skim, may be //<span style="font-family: Arial,Helvetica,sans-serif;">pure //<span style="font-family: Arial,Helvetica,sans-serif;"> (fit for human consumption) by public health standards, but it is not //<span style="font-family: Arial,Helvetica,sans-serif;">pure //<span style="font-family: Arial,Helvetica,sans-serif;"> in the chemical sense. Milk is a mixture of a great many substances, including water, butterfat, proteins, and sugars. Each of these substances is present in different amounts in each of the different kinds of milk (Figure 1.1).



A mixture consists of two or more pure substances. Most of the matter we see around us is composed of mixtures. Seawater contains dissolved salts; river water contains suspended mud; hard water contains salts of calcium, magnesium, and iron. Both seawater and river water also contain dissolved oxygen, without which fish and other aquatic life could not survive.
 * **<span style="font-family: Arial,Helvetica,sans-serif;">FIGURE 1.1 **<span style="font-family: Arial,Helvetica,sans-serif;"> Pure substances versus mixtures. The labels on a carton of milk and a box of baking soda show that milk is a mixture and baking soda is a pure substance. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">Mixtures[[image:http://genchem.chem.wisc.edu/sstutorial/cTutorial.GIF width="143" height="29" align="texttop" link="http://genchem.chem.wisc.edu/sstutorial/Text1/Tx12/Mixtures/mixture.htm"]] ** <span style="font-family: Arial,Helvetica,sans-serif;">

Unlike the constant composition of a simple substance, the composition of a mixture can be changed. The properties of the mixture depend on the percentage of each pure substance in it. Steel is an example of a mixture. All steel starts with the pure substance iron. Refiners then add varying percentages of carbon, nickel, chromium, vanadium, or other substances to obtain steels of a desired hardness, tensile strength, corrosion resistance, and so on. The properties of a particular type of steel depend not only on which substances are mixed with the iron but also on the relative percentage of each. One type of chromium-nickel steel contains 0.6% chromium and 1.25% nickel. Its surface is easily hardened, a property that makes it valuable in the manufacture of automobile gears, pistons, and transmissions. The stainless steel used in the manufacture of surgical instruments, food-processing equipment, and kitchenware is also a mixture of iron, chromium, and nickel; it contains 18% chromium and 8% nickel. Steel with this composition can be polished to a very smooth surface and is very resistant to rusting.



You can often tell from the appearance of a sample whether it is a mixture. For example, if river water is clouded with mud or silt particles, you know it is a mixture. If a layer of brown haze lies over a city, you know the atmosphere is mixed with pollutants. However, the appearance of a sample is not always sufficient evidence by which to judge its composition. A sample of matter may look pure without being so. For instance, air looks like a pure substance but it is actually a mixture of oxygen, nitrogen, and other gases. Rubbing alcohol is a clear, colorless liquid that looks pure but is actually a mixture of isopropyl alcohol and water, both of which are clear, colorless liquids. As another example, you cannot look at a piece of metal and know whether it is pure iron or a mixture of iron with some other substance such as chromium or nickel. Figure 1.2 shows the relationships between different kinds of matter.



<span style="font-family: Arial,Helvetica,sans-serif; font-size: 80%;">taken from : [|//http://genchem.chem.wisc.edu/sstutorial/Text1/Tx12/tx12.html//]

<span style="display: block; font-family: Tahoma,Geneva,sans-serif; font-size: 130%; text-align: center;">**The Four //Aristotelian// Elements**

<span style="font-family: Arial,Helvetica,sans-serif;">

we stern chemistry grew up around old alchemical ideas of Earth, Air, Fire, and Water – the so called //Aristotelian elements// – a concept that originated with the ancient Greeks and others, [|here]. <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">
 * <span style="font-family: Arial,Helvetica,sans-serif;">Read more about the [|Four Elements] in Carmen Giunta's **Elements and Atoms: Case Studies in the Development of Chemistry**, [|here].
 * <span style="font-family: Arial,Helvetica,sans-serif;">Fathi Habashi of Laval University discusses **Zoroastra and The Theory of Four Elements**, here, and **Cambodia's Four Elements,** here.

<span style="font-family: Arial,Helvetica,sans-serif;">**The Year 1800: Organic & Inorganic Matter** In the year 1800 some 27 chemical elements were known:

Ideas had moved on from the four Aristotelian elements, and it was thought that there were //two// distinct types of matter: //organic// and //inorganic//.
 * <span style="font-family: Arial,Helvetica,sans-serif;">//Organic matter// was associated with living things (biological origin: flora, forna, food, us) and was assumed to possess a //vital-force//, an indefinable characteristic that separated living organisms and materials derived from living organisms from inanimate //inorganic matter//:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Inorganic matter is of geological origin: minerals, rock, sea, air

<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">**New Ideas: Urea and an Unanswerable Challenge the Vital-Force Theory** In the nineteenth century chemical knowledge increased dramatically:

In 1804, Dalton proposed that matter was constructed from identical, indivisible atoms which combined with each other in constant, or //stoichiometric//, proportions. In 1828 the classical distinction between organic and inorganic matter was resolved as evidence accumulated that organic materials could be synthesised in the laboratory from inorganic, non-living sources. The crucial step occurred when the German chemist Friedrich Wohler heated ammonium cyanate, an inorganic salt, and produced the substance [|urea], H2NCONH2, that was //identical// to organic urea isolated from the urine of animals, and so was organic. Wohler's synthesis of an organic chemical from inorganic starting materials was an unanswerable challenge to the vital-force theory. By the end of the nineteenth century chemical methodology had become very sophisticated. <span style="font-family: Arial,Helvetica,sans-serif;">Three points:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Scientists understood that atom types could be classified and grouped into a periodic table of chemical elements, and by 1900 the only non-radioactive s, p or d-block element that remained to be discovered was rhenium, Re.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Common pharmaceutical preparations such as opium, tobacco and coca were shown to have active ingredients that were discrete molecular entities (morphine, nicotine & cocaine, respectively) that could be purified to white crystalline materials (usually as the .HCl salt) of known chemical composition.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Most materials obtained from nature, organic and inorganic, are chemically complex, heterogeneous mixtures or composites.
 * <span style="font-family: Arial,Helvetica,sans-serif;">It is now generally recognised that many classically defined inorganic materials, such as limestone, coal and the oxygen in our atmosphere are actually of biological origin, produced over geological time scales.
 * <span style="font-family: Arial,Helvetica,sans-serif;">The modern chemical classification system says that to be "organic" a substances possess carbon hydrogen (C-H) chemical bonds, and that "inorganic" substances do not possess C-H bonds. Under this system, oxygen is inorganic. And, ironically, so is urea, H2NCONH2.

<span style="font-family: Arial,Helvetica,sans-serif;">**The Chemical Classification of Matter** Many chemistry textbooks provide a diagram In their introductory sections showing how matter can be classified into mixtures and pure substances, and then to heterogeneous and homogeneous mixtures, elements and compounds:


 * Matter**, the stuff from which our physical world is formed, presents to us as various types of //material//. On a first analysis, the possible phases are:


 * <span style="font-family: Arial,Helvetica,sans-serif;">gaseous, such as air
 * <span style="font-family: Arial,Helvetica,sans-serif;">liquid, such as water
 * <span style="font-family: Arial,Helvetica,sans-serif;">solid, such as rock

<span style="font-family: Arial,Helvetica,sans-serif;">However, for classification purposes it is useful to divide materials into:


 * <span style="font-family: Arial,Helvetica,sans-serif;">**mixtures**: variable composition
 * <span style="font-family: Arial,Helvetica,sans-serif;">**pure substances**: stoichiometric composition

<span style="font-family: Arial,Helvetica,sans-serif;">Physical techniques, such as: distillation, filtration, crush-&-sort, selective dissolution, chromatography, etc., can be used to separate the individual components of a mixture into chemically pure substances, and physical methods such as turbulent mixing can be used to blend pure substances together into mixtures.

<span style="font-family: Arial,Helvetica,sans-serif;">**The Chemical Classification of Matter: Updated** However, the above graphic is a little over simple for our purposes, and can be usefully expanded to a classification system is both derived from and is compatible with the classification system employed in The Chemical Thesaurus reaction chemistry database: <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"> However, scale is important: a 1.0 m3 sample of air will be homogeneous but the atmosphere as a whole is heterogeneous. Poorly stirred solutions where there is chemistry occurring, even simple heating, are liable to become heterogeneous.
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Mixtures** can be sub classified into four types: homogeneous, heterogeneous, colloidal and composite. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Homogeneous Mixtures** can all be regarded as solutions, and they can form in [|various ways]:
 * <span style="font-family: Arial,Helvetica,sans-serif;">mixture of two or more gases
 * <span style="font-family: Arial,Helvetica,sans-serif;">gases dissolved in liquids
 * <span style="font-family: Arial,Helvetica,sans-serif;">mixture of two or more miscible liquids
 * <span style="font-family: Arial,Helvetica,sans-serif;">solid fully dissolved in a liquid By definition, any region of a homogeneous solution will be chemically identical to any other region so sampling is not an issue. A common way to insure that a homogeneous mixture remains homogeneous is by turbulent mixing. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Heterogeneous Mixtures** are agglomerates. In the natural world, nearly all matter is heterogeneous, apart from air, fresh clear water and various minerals: quartz, rock salt, sulfur etc.

Generally, chemists dislike heterogeneous mixtures and materials. This is because chemists are interested in the composition of a particular piece of matter and how it behaves chemically. But, by definition, the composition of a heterogeneous material varies from region to region, where the distance between regions may range from microns to kilometres. A farmer may want to know the boron levels because B is an important trace element for crop growth. Somebody will have to take samples from all over the farm, perform chemical analysis of all the samples and perform a statistical analysis of the data because the soil is heterogeneous and will vary in boron levels from place to place. On the other hand, if the farmer wants to know the pH of the swimming pool only a single sample is required because the pool will be homogeneous. Chemists go to great lengths to homogenise heterogeneous matter. They grind and sort, but the favoured methods are dissolution, distillation and filtration. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Colloids** are defined [|thus]:

"A colloid is a heterogeneous mixture composed of tiny particles suspended in another material. The particles are larger than molecules but less than 1 µm in diameter. Particles this small do not settle out and pass right through filter paper. Milk is an example of a colloid. The particles can be solid, tiny droplets of liquid, or tiny bubbles of gas; the suspending medium can be a solid, liquid, or gas (although gas-gas colloids aren't possible)." Colloids often appear to be homogeneous in bulk, but when are examined under a microscope are observed to be heterogeneous. Chemists must treat colloids as heterogeneous and process colloids to homogeneous before analysis. || It is difficult to say how exactly many elements there are because:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Many real world solid materials are **composites**:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Many inorganic materials like rock are composite. Granite is a mixture of of feldspar (65-90%), quartz (10 to 60%) and biotite or mica (10 to 15%).
 * <span style="font-family: Arial,Helvetica,sans-serif;">Wood is an organic composite of consisting of cellulose and lignin.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Yeast in block form looks rather like a pure substance, but it is of course an extraordinarily complex, living biomaterial.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Glass Reinforced Plastic, GRP, is a composite of glass fibre in a crosslinked polymer resin.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Many industrial chemical products may have names that make then appear to be pure substances, but are actually highly complex mixtures of: active ingredient, binder, stabilisers, accelerators, lubricants, etc. For example, aspirin is a tablet consisting of many components including the active ingredient acetylsalicylic acid, calcium carbonate, magnesium stearate, etc., and these may change with time. Likewise, dynamite is not a substance, but a mixture of nitroglycerine, kieselguhr (diatomaceous earth), stabilisers, etc. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Pure Substances** have a fixed, stoichiometric composition: Ne, NaCl, O2, S8, CO2, C6H12O6, etc. Pure substances are also materials. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Elemental substances** are collections of atoms with the same proton number. Most elements consist of a mixture of isotopes. This is not usually an issue, however, isotopes can be separated (enriched or depleted) in various ways.

There are 81 non-radioactive elements. All elements heavier than barium, Ba, atomic number 83, are radioactive, are technetium, 43, and promethium, 61. Some radioactive elements have isotopes with half lives close to a billion years, and these still exist on Earth: 235U and 238U are well known examples. Others, atomic number 93 to 118 (but not 117) must be prepared synthetically and may exist for microseconds or less. There are 92 naturally occuring elements. || <span style="font-family: Arial,Helvetica,sans-serif;">Molecular materials exhibit a vast array of properties, but they are //generally// mechanically weak, have low electrical conductivity, have low melting and boiling points, and/or a susceptibility to sublime. Molecular materials usually soluble in (or miscible with) non-polar solvents. Hydrogen bonded molecular solids are often soluble in water. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Binary compound substances** consist of just two elements with the constraint [used //here//] that there is just one type of strong bond present: metallic, ionic or covalent. This definition includes methane, CH4, but not ethane, CH3CH3, or the other hydrocarbons which possess both C-H and C-C bonds. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**The Laing Tetrahedron** of bonding and material type, discussed in detail here, appears on this page because pure elements and substances consisting of only two elements but with only one type of strong chemical bond – exhibit four extremes of material type: metals, ionic salts, molecular substances, network covalent materials, or they are intermediate between these four extremes. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Ternary and polyelemental compound substances** include chloromethane, CH3Cl, methanol, CH3OH, and glucose, C6H12O6. There substances have multiple types of chemical bonds of varying polarity. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Chemical Substance Types** ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Network covalent materials** have atoms arranged in an extended lattice of strong, "shared electron pair" covalent bonds. Materials are generally hard, refractory solid substances. They are poor electrical conductors, and they are not soluble in any solvent. Very high melting point (>1500°C). Chemically intractable materials. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Metallic elements** are modelled as a single type of atom arranged as a lattice of cations immersed in a sea of mobile valence electrons delocalised over the entire crystal. Electrons are the agents responsible for the conduction of electricity and heat. Metals have a characteristic lustre, are often ductile and exhibit a huge range of melting points, from mercury, -39°C, to tungsten at 3200°C. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Alloys** are metallic materials consisting of a melt of two or more metals that is cooled to the solid phase. If can only be determined if an alloy is heterogeneous, homogeneous or stoichiometric by microscopic, physical and chemical examination, see [|here]. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Molecular substances** consist of discrete molecules. Materials held together <span style="font-family: Arial,Helvetica,sans-serif;">internally by strong intramolecular (within molecule) "shared electron pair" covalent bonds, but when forming condensed solid or liquid phases, the molecules interact via weak intermolecular (between molecule) van der Waals forces:
 * <span style="font-family: Arial,Helvetica,sans-serif;">There are several types of [|van der Waals] attraction: dipole/dipole, dipole/induced-dipole and spontaneous-dipole/induced-dipole. It is tempting to consider these forces to be of different strengths, but it is the distance range that is more important. The spontaneous-dipole/induced-dipole attractions – also known as London dispersion forces (LDF) – are surprisingly strong but only act at //very// short range. (It is as if the surface of even neutral, non-polar molecules like methane are 'sticky'.)
 * <span style="font-family: Arial,Helvetica,sans-serif;">All molecules have London dispersion forces and the strength increases with the size/surface area of the molecule. This logic is used to explains the increasing boiling and sublimation temperatures of the halogens: F2 < Cl2 < Br2 I2.
 * <span style="font-family: Arial,Helvetica,sans-serif;">In addition, some molecules have dipole-dipole, hydrogen bonding, etc., which increase the total amount of interaction between the molecules. Consider iodine chloride,<span style="font-family: Times New Roman,Times,serif;"> ICl and bromine, Br2. Both are 70-electron systems, but <span style="font-family: Times New Roman,Times,serif;">ICl is polar and Br2 is non-polar, yet they have rather similar boiling points of 97° and 59° respectively, showing that the dipole/dipole attraction makes only a minor contribution. (Many thanks to members of the [|ChemEd list] for the above points.)
 * <span style="font-family: Arial,Helvetica,sans-serif;">Molecular materials may also be hydrogen bonded, where a hydrogen bond involves a proton being shared between two Lewis bases, usually with oxygen, nitrogen or fluorine atomic centres, as discussed [|here].
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Simple ionic salts**, like sodium chloride, Na+ Cl–, have a crystal lattice with anions electrostatically attracted to adjacent cations and cations electrostatically attracted to adjacent anions. Simple ionic materials are insulators as solids, but are electrical conductors when molten and when dissolved in aqueous solution. Simple ionic materials may be soluble in water (and sometimes in dipolar aprotic solvents such as DMSO), but they are insoluble in non-polar solvents like hexane. Simple ionic materials have moderately high melting points, usually 300-1000°C. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Molecular and complex salts** have a crystal lattice anions and cations electrostatically attracted to each other, but the cations and anions are compound entities. Some properties of molecular and complex salts are dominated by the ionic nature of the material. For example, substances are more soluble in water than organic solvents, indeed, many complex ions are only stable in aqueous solution. Other properties are dominated by the molecular nature of the ions. For example, melting points tend to be low or substances decompose on heating. Solubility is often pH dependent. Examples include:

sodium acetate Na+ CH3COO– ammonium nitrate [NH4]+[NO3]– hexaaquacopper(II) chloride [Cu(H2O)6]2+ 2Cl– || //<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 80%; text-align: right;">taken from: http://www.meta-synthesis.com/webbook/31_matter/matter.html //
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Intermediate materials** are between ionic, molecular and network. Examples include metal oxides, such as magnesium oxide and calcium oxide, as well as metal sulfides and phosphides. This topic is discussed in detail [|here]. ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">**Polymers** consist of a large number of identical monomer components linked together in a chain, and there maybe cross linking between chains. Properties such as melting point and crystallinity are determined more by chain length and the degree of cross linking than by the nature of the monomer entities or their bonding.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Polymers consisting of long chains, such as low density polyethylene, are essentially molecular and are often thermoplastic and melt on heating.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Extensively crosslinked polymers, such as the and melamine-formaldehyde are network covalent materials that do not melt. Light fittings and electrical plugs are normally made from such polymers. ||

media type="youtube" key="gCgTJ6ID6ZA" width="507" height="419" align="center"

<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 80%; text-align: right;">taken from:http://www.youtube.com/watch?v=gCgTJ6ID6Z A <span style="color: #ff0000; display: block; font-family: Tahoma,Geneva,sans-serif; font-size: 130%; text-align: center;">

<span style="font-family: Arial,Helvetica,sans-serif;">**The Year 1800: Organic & Inorganic Matter** In the year 1800 some 27 chemical elements were known:

<span style="font-family: Arial,Helvetica,sans-serif;">Ideas had moved on from the four Aristotelian elements, and it was thought that there were //two// distinct types of matter: //organic// and //inorganic//.
 * <span style="font-family: Arial,Helvetica,sans-serif;">//Organic matter// was associated with living things (biological origin: flora, forna, food, us) and was assumed to possess a //vital-force//, an indefinable characteristic that separated living organisms and materials derived from living organisms from inanimate //inorganic matter//:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Inorganic matter is of geological origin: minerals, rock, sea, air

<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">**New Ideas: Urea and an Unanswerable Challenge the Vital-Force Theory** In the nineteenth century chemical knowledge increased dramatically:

In 1804, Dalton proposed that matter was constructed from identical, indivisible atoms which combined with each other in constant, or //stoichiometric//, proportions. In 1828 the classical distinction between organic and inorganic matter was resolved as evidence accumulated that organic materials could be synthesised in the laboratory from inorganic, non-living sources. The crucial step occurred when the German chemist Friedrich Wohler heated ammonium cyanate, an inorganic salt, and produced the substance [|urea], H2NCONH2, that was //identical// to organic urea isolated from the urine of animals, and so was organic. Wohler's synthesis of an organic chemical from inorganic starting materials was an unanswerable challenge to the vital-force theory. By the end of the nineteenth century chemical methodology had become very sophisticated. <span style="font-family: Arial,Helvetica,sans-serif;">Three points:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Scientists understood that atom types could be classified and grouped into a periodic table of chemical elements, and by 1900 the only non-radioactive s, p or d-block element that remained to be discovered was rhenium, Re.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Common pharmaceutical preparations such as opium, tobacco and coca were shown to have active ingredients that were discrete molecular entities (morphine, nicotine & cocaine, respectively) that could be purified to white crystalline materials (usually as the .HCl salt) of known chemical composition.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Most materials obtained from nature, organic and inorganic, are chemically complex, heterogeneous mixtures or composites.
 * <span style="font-family: Arial,Helvetica,sans-serif;">It is now generally recognised that many classically defined inorganic materials, such as limestone, coal and the oxygen in our atmosphere are actually of biological origin, produced over geological time scales.
 * <span style="font-family: Arial,Helvetica,sans-serif;">The modern chemical classification system says that to be "organic" a substances possess carbon hydrogen (C-H) chemical bonds, and that "inorganic" substances do not possess C-H bonds. Under this system, oxygen is inorganic. And, ironically, so is urea, H2NCONH2.

[]

<span style="font-family: Arial,Helvetica,sans-serif;">Material
<span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Some objects are made of material that seems to have a consistent compositon throughout. This might be a metal, glass, marble, plastic, paper, etc. Such material is referred to as "homogeneous". If the material obviously varies from one region to another, as seen in travertine, wood grains, particle board, are called "heterogeneous". The composition varies throughout a heterogenous material. Rocks can be homogeneous as is the case of fine-gained igneous rocks such as obsidion or heterogeneous as in the coarse-grained igneous rocks such as granite. Clear solutions are homogenous mixtures as is the air

<span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">A "substance" has a rather definte chemical composition. As such a substance is homogeneous. A salt solution is homogeneous but is not a substance because the chemical composition is quite arbitrary. It can range from very dilute to concentrated and still be a homogeneous material. A substance usually refers to materials such as salt, sugar, water, calcite, quartz, potassium chloride, all of which have definte ratios of their component elements. Nitrogen is a substance, air is not. Zinc or zinc oxide are sustances, bronze and brass are not. Ethanol is a substance, wine is not. Wine can have a wide range of compositions, ethanol contains definite ratios of carbon, hydrogen and oxygen combined in a certain way. A glass of water with ice-cubes is heterogeneous in that there different "phases" that have distinct boundaries and interfaces yet there is a single substance there (water). The ice is a solid phase, the water is a liquid phase.



__//**taken from:http://tannerm.com/kinds_of_matter.htm**//__



<span style="font-family: Arial,Helvetica,sans-serif;">**The Four //Aristotelian//  Elements** <span style="font-family: Arial,Helvetica,sans-serif;">Western chemistry grew up around old alchemical ideas of Earth, Air, Fire, and Water – the so called //Aristotelian elements// – a concept that originated with the ancient Greeks and others, [|here]. <span style="font-family: Arial,Helvetica,sans-serif;">
 * In the world exists thee kinds of Matter:
 * Liquid, Solid and Gas.
 * The Liquid don't have shape, it takes the shape of the glass or recipient is it put.
 * The solid have shape, and dont takes the form of the recipient is it put.
 * Yhe Gas dont have form or shape.but you can see it whit scientist instruments.

- http://www.meta-synthesis.com/webbook/31_matter/matter.html - Made by me
 * Taken From: