classification of matter
Chemists study the structures, physical properties, and
chemical properties of material substances. These consist of matter,
which is anything that occupies space and has mass. Gold and iridium are
matter, as are peanuts, people, and postage stamps. Smoke, smog, and laughing
gas are matter. Energy, light, and sound, however, are not matter; ideas and
emotions are also not matter.
Under normal
conditions, there are three distinct states of matter: solids, liquids,
and gases. Solids are relatively rigid and have fixed shapes
and volumes. A rock, for example, is a solid. In contrast, liquids have
fixed volumes but flow to assume the shape of their containers, such as a beverage
in a can. Gases, such as air in an automobile tire, have neither
fixed shapes nor fixed volumes and expand to completely fill their containers.
Whereas the volume of gases strongly depends on their temperature and pressure (the
amount of force exerted on a given area), the volumes of liquids and solids are
virtually independent of temperature and pressure. Matter can often change from
one physical state to another in a process called a physical change.
For example, liquid water can be heated to form a gas called steam, or steam
can be cooled to form liquid water. However, such changes of state do not
affect the chemical composition of the substance.
Evidence suggests that substances are made up of smaller particles
that are ordinarily moving around. Some of those particles of matter can be
split into smaller units using fairly strong heat or electricity into smaller
rather uniform bits of matter called atoms. Atoms are the building blocks of
elements. Elements are all those substances that have not ever been
decomposed or separated into any other substances through chemical reactions,
by the application of heat, or by attempting to force an direct
electric current through the sample. Atoms in turn have been found to be made
up of yet smaller units of matter called electrons, protons, and
neutrons.
Figure 1: Breakdown of an atom. An
illustration of the helium atom, depicting the nucleus (pink) and the electron
cloud distribution (black). The nucleus (upper right) in helium-4 is in reality
spherically symmetric and closely resembles the electron cloud, although for
more complicated nuclei this is not always the case. The black bar is one
angstrom (10−10 m or 100 pm). Image used with permissin
from Wikipedia.
Elements
can be arranged into
what is called the periodic table of
elements based on observed similarities in chemical and physical properties
among the different elements. When atoms of two or more elements come together
and bond, a compound is formed. The compound formed can later be broken
down into the pure substances that originally reacted to form it.
Compounds
such as water are
composed of smaller units of bonded atoms called molecules. Molecules of a
compound are composed of the same proportion of elements as the compound as a
whole since they are the smallest units of that compound. For example,
every portion of a sample of water is composed of water molecules. Each water
molecule contains two hydrogen atoms and one oxygen atom, and so water as a
whole has, in a combined state, twice as many hydrogen atoms as oxygen atoms..
Water can still consist of the same molecules, but its physical
properties may change. For instance, water at a temperature below 0°
Celsius (32° Fahrenheit) is ice, whereas water above the temperature of
100° C (212° F) is a gas, water vapor. When matter changes from one state
to another, temperature and pressure may be involved in the process
and the density and other physical properties change. The temperature and
pressure exerted on a sample of matter determines the resulting form of that
the matter takes, whether solid, liquid, or gas.
Since the properties of compounds and elements are uniform, they
are classified as substances. When two or more substances are
mixed together, the result is called a mixture. Mixtures can be classified into
two main categories: homogeneous and heterogeneous.
Relationships between the Types of Matter and the
Methods Used to Separate Mixtures
Summary
Matter can be classified according to physical and
chemical properties. Matter is anything that occupies space and
has mass. The three states of matter are solid, liquid,
and gas. A physical change involves the conversion of a substance
from one state of matter to another, without changing its chemical composition.
Most matter consists of mixtures of pure substances, which can
be homogeneous (uniform in composition)
or heterogeneous (different regions possess different compositions
and properties). Pure substances can be either chemical compounds or
elements. Compounds can be broken down into elements by chemical
reactions, but elements cannot be separated into simpler substances
by chemical means. The properties of substances can be classified as either
physical or chemical. Scientists can observe physical
properties without changing the composition of the substance,
whereas chemical properties describe the tendency of a substance to
undergo chemical changes (chemical reactions) that change its chemical
composition. Physical properties can be intensive or extensive. Intensive
properties are the same for all samples; do not depend on sample size; and
include, for example, color, physical state, and melting and boiling
points. Extensive properties depend on the amount of material and
include mass and volume. The ratio of two extensive properties, mass and
volume, is an important intensive property called density.
Refference
wikipedia.org
In the gas phase, is the matter have a fixed?
BalasHapusIn the gas phase, matter does not have a fixed volume or shape. This occurs because the molecules are widely separated with the spaces between the particles typically around ten times further apart in all three spatial directions, making the gas around 1000 times less dense than the corresponding liquid phase at the same temperature.The particles in a gas move in a rather random and independent fashion, bouncing off each other and the walls of the container.
Hapuscan you explain more about solid phase???
BalasHapusWhen the temperature of a liquid is lowered to the freezing point of the substance (for water the freezing point is 0oC), the movement of the particles slows with the spacing between the particles changing until the attractions between the particles lock the particles into a solid form. At the freezing point, the particles are closely packed together and tend to block the motions of each other. The attractions between the particles hold the particles tightly together so that the entire ensemble of particles takes on a fixed shape. The volume of the solid is constant and the shape of a solid is constant unless deformed by a sufficiently strong external force.
HapusIn a solid the particles remain in a relatively fixed positions but continue to vibrate. The vibrating particles in a solid do not completely stop moving and can slowly move into any voids that exist within the solid.
Shabrina, can you give me a example for the homogeneus mixture?
BalasHapusall portions of a material are in the same state, have no visible boundaries, and are uniform throughout, then the material is homogeneous. Examples of homogeneous mixtures are the air we breathe and the tap water we drink.
HapusAtom is the smallest part of the material that has not be divided again. My question is there anything smaller than an atom???
BalasHapusAtoms in turn have been found to be made up of yet smaller units of matter called electrons, protons, and neutrons.
BalasHapusWho invented the first atomic and how its history ?>
BalasHapusn chemistry and physics, atomic theory is a scientific theory of the nature of matter, which states that matter is composed of discrete units called atoms. It began as a philosophical concept in ancient Greece and entered the scientific mainstream in the early 19th century when discoveries in the field of chemistry showed that matter did indeed behave as if it were made up of atoms.
HapusThe word atom comes from the Ancient Greek adjective atomos, meaning "indivisible".[1] 19th century chemists began using the term in connection with the growing number of irreducible chemical elements. While seemingly apropos, around the turn of the 20th century, through various experiments with electromagnetism and radioactivity, physicists discovered that the so-called "uncuttable atom" was actually a conglomerate of various subatomic particles (chiefly, electrons, protons and neutrons) which can exist separately from each other. In fact, in certain extreme environments, such as neutron stars, extreme temperature and pressure prevents atoms from existing at all. Since atoms were found to be divisible, physicists later invented the term "elementary particles" to describe the "uncuttable", though not indestructible, parts of an atom. The field of science which studies subatomic particles is particle physics, and it is in this field that physicists hope to discover the true fundamental nature of matter.
what only three phase of matter?
BalasHapusRegardless of the type of molecule, matter normally exists as either a solid, a liquid, or a gas. We call this property of matter the phase of the matter. The three normal phases of matter have unique characteristics which are listed on the slide.
Hapuscan you give me a example for the heterogeneus mixture? and difference with homogeneus mixture ?
BalasHapusSand shaken up in a bottle of water is a heterogeneous mixture of sand particles floating around which will eventually settle to the bottom of the bottle, making it look a lot less like a mixture.
Hapushomogeneous mixture is a mixture that cannot be filtered or easily broken down (like juice, air, and hydrogen peroxide) but a heterogeneous mixture is still just a combination of two or more substances in which each substance retains its individual characteristics and properties (basically like trail mix or a salad).
Why every atom that consists of one group has different properties ??
BalasHapuscause the atomic number, the number of protons. There are certain number of protons, neutral neutrons and electrons. If you know that a atom is neutral neutral atoms mean that the number of protons is the same as the number of electrons
Hapuswhat is the chemical properties of substance
BalasHapusThe element of the particle can be an atom / molecule element. Elements whose particles are atoms, meaning they can stand on their own or contain only one atom, they are written with the elemental emblem, Material / Substance is generally divided into two parts: single and mixed substances. A single substance can be an element, or. See example of heterogeneous mixture.
Hapus