Phases and Classification of Matter

Matter states

Matter is defined as anything that occupies space and has mass, and it is all around us. Solids and liquids are more obviously matter: We can see that they take up space, and their weight tells us that they have mass. Gases are also matter; if gases did not take up space, a balloon would stay collapsed rather than inflate when filled with gas.

Solid State

For metals such as gold or plutonium, this lattice is typically crystalline, allowing properties such as rigidity, density, and electrical conductivity. Energy levels are low enough that atomic bonds remain intact and long-range order is preserved.

Liquid State

The lattice structure collapses into a short-range order: particles continuously rearrange while remaining in contact. Liquids flow, transmit pressure efficiently, and exhibit surface tension. This state emerges when thermal energy overcomes the rigidity of the solid lattice but not the cohesion between particles.

Gas State

Interatomic forces are negligible compared to kinetic energy. Gases expand to fill available space, are highly compressible, and have low density. This state occurs when thermal energy fully overcomes cohesive forces, allowing particles to behave independently.

Plasma State

Unlike ordinary gases, plasma is electrically conductive, emits intense radiation, and responds strongly to electromagnetic fields. Collective behaviour dominates over individual particle motion. In this state, conventional chemical structure ceases to exist—matter is governed primarily by electromagnetic and nuclear-scale interactions.

Plasma represents the highest-energy classical state of matter, commonly found in stars, lightning, and high-energy astrophysical or laboratory phenomena.

Mass & Weight

The matter under investigation may exist as a complex assembly of diverse substances. Such specimens may take the form of chemical compounds, homogeneous solutions, or heterogeneous aggregates, often appearing as a collection of varied samples. Whether one observes a singular substance or a multifaceted mixture, the properties of the object of study are determined by both its chemical composition and the physical state of its constituent parts.

Certain substances manifest characteristics associated with multiple states of matter simultaneously. This phenomenon is frequently observed in granular materials, where the bulk sample is composed of myriad discrete particles. Sand, for instance, may be 'poured' in a manner suggestive of a liquid, yet it consists of individual grains that remain resolutely solid. Furthermore, matter may exhibit properties of various states when it exists as a mixture. A notable example is found in clouds; while they appear to behave as a gas, they are in fact aerosols—mixtures comprised of air in its gaseous state and minute particles of water, which may be either liquid droplets or solid ice crystals.

The mass of a body constitutes a measure of the quantity of matter contained within it. One fundamental method of ascertaining an object’s mass involves determining the magnitude of force required to impart a specific acceleration; for instance, a far greater force is necessitated to accelerate a motor car than a bicycle, owing to the car's vastly superior mass. In common practice, however, mass is more frequently determined by employing a balance, an instrument used to compare the unknown mass of an object against a standardised reference mass.

Whilst weight is fundamentally associated with mass, it is imperative to distinguish between these two concepts. Weight denotes the gravitational force exerted upon a body, a magnitude that exists in direct proportion to that body’s mass. Consequently, whereas the weight of an object fluctuates in accordance with the local intensity of gravitation, its mass remains an invariant property. Consider, for instance, an astronaut: her mass remains unaltered by her arrival upon the lunar surface, yet her weight is reduced to a mere sixth of its terrestrial value, as the Moon’s gravitational pull is but a fraction of the Earth’s. Though she may experience a sensation of 'weightlessness' when external forces are negligible, she is, in a physical sense, never 'massless', for the quantity of matter she comprises remains constant.

The Law of Conservation of Matter

Summarizes many scientific observations about matter: It states that there is no detectable change in the total quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical change). Brewing beer and the operation of batteries provide examples of the conservation of matter.

Within an isolated container, we place several constituent ingredients; for our purpose, let the final contents include wheat, water, sugar, egg, salt, and olive oil. This vessel is then subjected to a vibrating mixer to achieve a uniform composition. Subsequently, the container is placed within an oven and baked at 200°C (400°F) for a duration of thirty to thirty-five minutes.

The vessel itself is designed with a discrete secondary section, featuring a non-return valve mechanism and a chamber constructed from thermally resilient rubber. Before the commencement of the baking process, the container is weighed, and the total gross weight is meticulously recorded.

Conservation of matter experiment

This experiment illustrates that the initial, unmodified matter and the subsequent 'soup' of the post-baking product remain equal in weight. Consequently, their mass is also proven to be equal, as the measurements were conducted in the same location and under identical environmental conditions.

Whilst this law of conservation holds true for every conversion of matter, convincing demonstrations are notably rare in common experience. This scarcity arises because, outside of the stringent conditions maintained within a laboratory, one seldom succeeds in collecting the entirety of the substances produced during a specific transformation. Consider, for instance, the biological processes of ingestion and digestion: although all matter from the original food is strictly preserved, a significant portion is assimilated into the body's own structure, while the remainder is voided as various forms of waste. Consequently, the empirical verification of this law through direct measurement remains a formidable challenge in such complex systems.

Furthermore, as may have been observed, we have engineered certain sophisticated apparatus—notably the chamber featuring dynamic volume capabilities and the other refinements detailed in our experimental description—to render our observations transparent. These innovations serve to demonstrate that the reality of physical systems is a multifaceted matter, frequently contingent upon the complexities of the world at large, which functions as an open system.

One must also acknowledge the paramount importance of a rigorous scientific approach: throughout one's scholarly pursuits, it is essential to account for both the theoretical, idealised isolated environment and the open systems encountered in the natural world.

Atoms and Molecules

An atom represents the most minute particle of an element which retains the inherent properties of that substance and is capable of entering into chemical combination. Consider, by way of illustration, the element gold. Conceive of the act of bisecting a gold nugget, thereafter dividing the resulting portions repeatedly until there remains a fragment of gold so diminutive that it defies further division, irrespective of the fineness of the instrument employed. This ultimate, irreducible portion constitutes an atom—a term derived from the Greek atomos, signifying ‘indivisible’. This atom would no longer be gold if it were divided any further.

The initial postulate that matter is composed of atoms is ascribed to the Greek philosophers Leucippus and Democritus, who formulated their doctrines in the fifth century BCE. Nevertheless, it was not until the dawn of the nineteenth century that John Dalton (1766–1844), a British schoolmaster possessing a profound devotion to scientific enquiry, substantiated this hypothesis through rigorous quantitative measurements.

Since that epoch, repeated experimentation has corroborated numerous facets of this hypothesis, and it has subsequently ascended to the position of a cornerstone theory within the realm of chemistry. Certain other tenets of Dalton’s atomic theory remain in use to this day, albeit subject to minor emendations; a comprehensive exposition of these principles is provided in the subsequent discourse on atoms and molecules.

Macroscopic photo: nugget of a gold (Au).

Microscopic image of the gold structure in a solid state.

An atom possesses a magnitude so infinitesimal that its dimensions remain exceedingly difficult for the human mind to conceive. Amongst the most minute objects discernible to the unaided eye is a single thread of a spider's web; such strands measure approximately cm (0.0001 cm) in diameter. Whilst the cross-section of a single strand is well-nigh impossible to perceive without the aid of a microscope, it remains colossal when measured against an atomic scale. A single carbon atom within said web possesses a diameter of approximately cm (0.000000015 cm); consequently, it would require some 7,000 carbon atoms to span the diameter of a single strand. To provide the pupil with a clearer perspective: should a carbon atom be magnified to the size of a small coin, the cross-section of the spider's strand would then exceed the dimensions of a football pitch, necessitating approximately 150 million such "coins" to cover its surface.

Ripened cotton boll

The structural level

The cellular level of cotton tissue organisation

Molecular structure of the fibrous organic tissues of the cotton flower

Schema of a singular organic molecule within the cotton tissue

An atom is so light that its mass is also difficult to imagine. A billion lead atoms (1,000,000,000 atoms) weigh about grams, a mass that is far too light to be weighed on even the world’s most sensitive balances. It would require over 300,000,000,000,000 lead atoms (300 trillion, or to be weighed, and they would weigh only 0.0000001 gram.

It is rare to find collections of individual atoms in nature. Only a select few elements, such as the noble gases helium, neon, and argon, consist of individual atoms that move independently of one another. Other elements, such as the gases hydrogen, nitrogen, oxygen, and chlorine, are composed of discrete units that consist of pairs of atoms.

It is rare to find collections of individual atoms. Only a few elements, such as the gases helium, neon, and argon, consist of a collection of individual atoms that move about independently of one another. Other elements, such as the gases hydrogen, nitrogen, oxygen, and chlorine, are composed of units that consist of pairs of atoms.

One form of the element phosphorus consists of units composed of four phosphorus atoms. The element sulphur exists in various forms, one of which consists of units composed of eight sulphur atoms. These units are called molecules. A molecule consists of two or more atoms joined by strong forces called chemical bonds.

The atoms in a molecule move around as a unit, much like the cans of soda in a six-pack or a bunch of keys joined together on a single key-ring. A molecule may consist of two or more identical atoms, as in the molecules found in the elements hydrogen, oxygen, and sulphur; or it may consist of two or more different atoms, as in the molecules found in water.

Each water molecule is a unit that contains two hydrogen atoms and one oxygen atom. Each glucose molecule is a unit that contains six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. Like atoms, molecules are incredibly small and light. If an ordinary glass of water were enlarged to the size of the Earth, the water molecules inside it would be about the size of golf balls.

Hydrogen

Oxygen

Phosphorus

Sulphur

Water

Carbon dioxide

Glucose

Classifying Matter

For simplification the situation at the bebining, we here will declare simple but well understandable mater classification definition, and distinguishing approach.

Of course this is only simplifyed introdyction for chemical classification technoques, but wh should to start from somewhat, and this is the place!

Matter may be classified into several distinct categories, two of which are mixtures and pure substances. A pure substance possesses a constant composition; consequently, all specimens of a pure substance exhibit exactly the same make-up and properties.

For instance, any sample of sucrose (table sugar) consists of 42.1% carbon, 6.5% hydrogen, and 51.4% oxygen by mass. Any specimen of sucrose also displays the same physical properties—such as melting point, colour, and sweetness—irrespective of the source from which it has been isolated.

Pure substances may be further divided into two distinct classes: elements and compounds.

Those pure substances which cannot be decomposed into simpler substances by means of chemical change are termed elements. Familiar examples among the more than one hundred known elements include iron, silver, gold, aluminium, sulphur, oxygen, and copper.

Of these elements, approximately ninety occur naturally upon the Earth, whilst some two dozen have been artificially created within laboratories.

Pure substances that can be broken down by chemical changes are called compounds. This breakdown may produce either elements or other compounds, or both. Mercury(II) oxide, an orange, crystalline solid, can be broken down by heat into the elements mercury and oxygen.

When heated in the absence of air, the compound sucrose is broken down into the element carbon and the compound water. (The initial stage of this process, when the sugar is turning brown, is known as caramelisation—this is what imparts the characteristic sweet and nutty flavour to caramel apples, caramelised onions, and caramel).

Silver(I) chloride is a white solid that can be broken down into its elements, silver and chlorine, by absorption of light. This property is the basis for the use of this compound in photographic films and photochromic eyeglasses (those with lenses that darken when exposed to light).

Mercury(II) oxide (HgO)

The compound decomposes into silvery droplets of liquid mercury and invisible oxygen gas.

The properties of combined elements are different from those in the free, or uncombined, state. For example, white crystalline sugar (sucrose) is a compound resulting from the chemical combination of the element carbon, which is a black solid in one of its uncombined forms, and the two elements hydrogen and oxygen, which are colourless gases when uncombined. Free sodium, an element that is a soft, shiny, metallic solid, and free chlorine, an element that is a yellow-green gas, combine to form sodium chloride (table salt), a compound that is a white, crystalline solid.

A mixture is composed of two or more types of matter that can be present in varying amounts and can be separated by physical changes, such as evaporation (you will learn more about this later). A mixture with a composition that varies from point to point is called a heterogeneous mixture. Italian dressing is an example of a heterogeneous mixture.

Its composition can vary because we can make it from varying amounts of oil, vinegar, and herbs. It is not the same from point to point throughout the mixture—one drop may be mostly vinegar, whereas a different drop may be mostly oil or herbs because the oil and vinegar separate and the herbs settle. Other examples of heterogeneous mixtures are chocolate chip cookies (we can see the separate bits of chocolate, nuts, and cookie dough) and granite (we can see the quartz, mica, feldspar, and more).

A homogeneous mixture, also called a solution, exhibits a uniform composition and appears visually the same throughout. An example of a solution is a sports drink, consisting of water, sugar, colouring, flavouring, and electrolytes mixed together uniformly.

Each drop of a sports drink tastes the same because each drop contains the same amounts of water, sugar, and other components. Note that the composition of a sports drink can vary—it could be made with somewhat more or less sugar, flavouring, or other components, and still be a sports drink. Other examples of homogeneous mixtures include air, maple syrup, petrol, and a solution of salt in water.

Although there are just over 100 elements, tens of millions of chemical compounds result from different combinations of these elements. Each compound has a specific composition and possesses definite chemical and physical properties by which we can distinguish it from all other compounds. And, of course, there are innumerable ways to combine elements and compounds to form different mixtures. A summary of how to distinguish between the various major classifications of matter is shown in the schema:

Eleven elements comprise approximately ninety-nine per cent of the Earth’s crust and atmosphere. Of this total quantity, oxygen constitutes nearly one-half, whilst silicon accounts for about one-quarter. The majority of elements upon the Earth are discovered in chemical combination with others; however, some one-quarter of the elements are also to be found in the free state.

Water Decomposition, Experiment vs Reality

Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply.

The breakdown of water involves a rearrangement of the atoms in water molecules into different molecules, each composed of two hydrogen atoms and two oxygen atoms, respectively. Two water molecules form one oxygen molecule and two hydrogen molecules.

The representation for what occurs, , will be explored in more depth in later chapters.

Decomposition of Water / Production of Hydrogen

The two gases produced have distinctly different properties. Oxygen is not flammable but is required for combustion of a fuel, and hydrogen is highly flammable and a potent energy source. How might this knowledge be applied in our world? One application involves research into more fuel-efficient transportation. Fuel-cell vehicles (FCV) run on hydrogen instead of gasoline

They are more efficient than vehicles with internal combustion engines, are nonpolluting, and reduce greenhouse gas emissions, making us less dependent on fossil fuels. FCVs are not yet economically viable, however, and current hydrogen production depends on natural gas. If we can develop a process to economically decompose water, or produce hydrogen in another environmentally sound way, FCVs may be the way of the future.

Concept of energy generation by hydrogen & oxigen chemical reaction