Dial Up Access Numbers

Dial-up is a way of accessing
the Internet with the help of a telephone line and a modem. The telephone line is connected to the modem, which in turn dials the number of the Internet Service Provider (ISP) to access the Internet. Most ISPs have a set of local or national numbers that users can dial to get connected to the Internet. These are known as the dial up access numbers.

Dial-up is popular, because all it requires is a computer with a modem and a telephone line. It is not as fast as broadband, but it is preferred due to easy availability and a low installation cost. Internet users can choose to pay their ISPs monthly or yearly. However, the call-charges add considerably to the cost. If the calls are charged on a fixed time basis, the cost is higher.

A modem is a device that sends digital data over a phone line. It is a short form used for modulator-demodulator (mo+dem). In order to dial the dial up access number, the telephone line must be connected to the modem.

The modem connects to the dial up access number provided by the ISP. It sets up a username and password and sends it to the server. Once the connection is made, a handshake takes place. This means data is exchanged between the modem and the remote server. Based on the information provided, access is granted to the Internet.

The dial up access numbers provided by the ISPs can be either local or national, or both. Generally they are local numbers since calling long distance is expensive.

Generally, the ISPs themselves provide all the information regarding the access numbers. The Internet can also be searched to find access numbers for any particular area. Still, it is best to confirm with the respective ISP whether the numbers are local or national.

ALL ABOUT BIOLOGY

BIOLOGY DEFINITION:
science of life: the science that deals with all forms of life, including their classification, physiology, chemistry, and interactions

Biology terminology

A
abdomen
In vertebrates, the portion of the trunk containing visceral organs other than heart and lungs; in arthropods, the posterior portion of the body, made up of similar segments and containing the reproductive organs and part of the digestive tract.
abiotic
[Gk. a, not, without + bios, life]
Nonliving; specifically, the nonliving components of an ecosystem, such as temperature, humidity, the mineral content of the soil, etc.
abscisic acid (ABA)
(ab-sis-ik) [L. ab, away, off + scissio, dividing]
A plant hormone that generally acts to inhibit growth, promote dormancy, and help the plant tolerate stressful conditions.
abscission
[L. ab, away, off + scissio, dividing]
In plants, the dropping of leaves, flowers, fruits, or stems at the end of a growing season, as the result of formation of a two-layered zone of specialized cells (the abscission zone) and the action of a hormone (ethylene).
absorption
[L. absorbere, to swallow down]
The movement of water and dissolved substances into a cell, tissue, or organism.
absorption spectrum
The range of a pigment's ability to absorb various wavelengths of light.
abyssal zone
(uh-bis-ul)
The portion of the ocean floor where light does not penetrate and where temperatures are cold and pressures intense.
acclimatization
(uh-kly-mih-ty-zay-shun)
Physiological adjustment to a change in an environmental factor.
accommodation
The automatic adjustment of an eye to focus on near objects.
acetylcholine
(asset-ill-coal-een)
One of the most common neurotransmitters; functions by binding to receptors and altering the permeability of the postsynaptic membrane to specific ions, either depolarizing or hyperpolarizing the membrane.
acetyl CoA
The entry compound for the Krebs cycle in cellular respiration; formed from a fragment of pyruvate attached to a coenzyme.
acid
[L. acidus, sour]
A substance that increases the hydrogen ion concentration in a solution.
acid precipitation
Rain, snow, or fog that is more acidic than pH 5.6.
acoelomate
(a-seel-oh-mate)
A solid-bodied animal lacking a cavity between the gut and outer body wall.
acrosome
(ak-ruh-some)
An organelle at the tip of a sperm cell that helps the sperm penetrate the egg.
ACTH
Abbreviation of adrenocorticotropic hormone.
actin
[Gk. aktis, a ray]
A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells.
action potential
A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels.
activation energy
The energy that must be possessed by atoms or molecules in order to react.
active site
The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds.
active transport
The movement of a substance across a biological membrane against its concentration or electrochemical gradient, with the help of energy input and specific transport proteins.
adaptation
[L. adaptare, to fit]
(1) The evolution of features that make a group of organisms better suited to live and reproduce in their environment. (2) A peculiarity of structure, physiology, or behavior that aids the organism in its environment.
adaptive peak
An equilibrium state in a population when the gene pool has allele frequencies that maximize the average fitness of a population's members.
adaptive radiation
The emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities and problems.
adenosine diphosphate (ADP)
A nucleotide consisting of adenine, ribose, and two phosphate groups; formed by the removal of one phosphate from an ATP molecule.
adenosine monophosphate (AMP)
A nucleotide consisting of adenine, ribose, and one phosphate group; can be formed by the removal of two phosphates from an ATP molecule; in its cyclic form, functions as a "second messenger" for a number of vertebrate hormones and neurotransmitters.
adenosine triphosphate (ATP)
An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.
adenylyl cyclase
An enzyme that converts ATP to cyclic AMP in response to a chemical signal.
ADH
Abbreviation of antidiuretic hormone.
adhesion
[L. adhaerere, to stick to]
The tendency of different kinds of molecules to stick together.
ADP
Abbreviation of adenosine diphosphate.
adrenal gland
(uh-dree-nul) [L. ad, near + renes, kidney]
An endocrine gland located adjacent to the kidney in mammals; composed of two glandular portions: an outer cortex, which responds to endocrine signals in reacting to stress and effecting salt and water balance, and a central medulla, which responds to nervous inputs resulting from stress.
adrenaline
A hormone, produced by the medulla of the adrenal gland, that increases the concentration of glucose in the blood, raises blood pressure and heartbeat rate, and increases muscular power and resistance to fatigue; also a neurotransmitter across synaptic junctions. Also called epinephrine. See Epinephrine.
adrenocorticotropic hormone (ACTH)
A hormone, produced by the anterior lobe of the pituitary gland, that stimulates the production of cortisol by the adrenal cortex.
adventitious
[L. adventicius, not properly belonging to]
Referring to a structure arising from an unusual place, such as roots growing from stems or leaves.
aerobic
(air-oh-bik) [Gk. aer, air + bios, life]
Containing oxygen; referring to an organism, environment, or cellular process that requires oxygen.
afferent
[L. ad, near + ferre, to carry]
Bringing inward to a central part, applied to nerves and blood vessels.
agar
A gelatinous material prepared from certain red algae that is used to solidify nutrient media for growing microorganisms.
age structure
The relative number of individuals of each age in a population.
agnathan
(ag-naa-thun)
A member of a jawless class of vertebrates represented today by the lampreys and hagfishes.
agonistic behavior
(ag-on-is-tik)
A type of behavior involving a contest of some kind that determines which competitor gains access to some resource, such as food or mates.
AIDS (acquired immunodeficiency syndrome)
The name of the late stages of HIV infection; defined by a specified reduction of T cells and the appearance of characteristic secondary infections.
aldehyde
(al-duh-hyde)
An organic molecule with a carbonyl group located at the end of the carbon skeleton.
aldosterone
(al-dah-stair-own) [Gk. aldaino, to nourish + stereo, solid]
An adrenal hormone that acts on the distal tubules of the kidney to stimulate the reabsorption of sodium (Na+) and the passive flow of water from the filtrate.
aleurone layer
[Gk. aleuron, flour]
The outermost cell layer of the endosperm of the grains (seeds) of wheat and other grasses; when acted upon by gibberellin, the aleurone layer releases enzymes that digest the stored food of the endosperm into small nutrient molecules that can be taken up by the embryo.
alga pl. algae
(al-gah, al-jee)
A photosynthetic, plantlike protist.
alkaline
Pertaining to substances that increase the relative number of hydroxide ions (OH–) in a solution; having a pH greater than 7; basic; opposite of acidic.
all-or-none event
An action that occurs either completely or not at all, such as the generation of an action potential by a neuron.
allantois
(al-an-toh-iss) [Gk. allant, sausage]
One of four extraembryonic membranes; serves as a repository for the embryo's nitrogenous waste.
allele
(al-eel) [Gk. allelon, of one another]
An alternative form of a gene.
allele frequency
The proportion of a particular allele in a population.
allergic reaction
An inflammatory response triggered by a weak antigen (an allergen) to which most individuals do not react; involves the release of large amounts of histamine from mast cells.
allometric growth
(al-oh-met-rik)
The variation in the relative rates of growth of various parts of the body, which helps shape the organism.
allopatric speciation
(al-oh-pat-rik) [Gk. allos, other + patra, fatherland, country]
A mode of speciation induced when the ancestral population becomes segregated by a geographical barrier.
allopolyploid
(al-oh-pol-ee-ploid)
A common type of polyploid species resulting from two different species interbreeding and combining their chromosomes.
allosteric site
(al-oh-steer-ik)
A specific receptor site on an enzyme molecule remote from the active site. Molecules bind to the allosteric site and change the shape of the active site, making it either more or less receptive to the substrate.
allozymes
Slightly different versions of the same enzyme, distinguishable via gel electrophoresis.
alpha helix
A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure.
alternation of generations
A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants.
alternative splicing
In alternative splicing, the same pre-mRNA molecule, which consists of introns and exons, is spliced in different ways to produce mature mRNAs of different lengths and different functionality.
altruistic behavior
(al-troo-is-tik)
The aiding of another individual at one's own risk or expense.
alveolus pl. alveoli
(al-vee-oh-lus) [L. dim. of alveus, cavity, hollow]
(1) One of the deadend, multilobed air sacs that constitute the gas exchange surface of the lungs. (2) One of the milk-secreting sacs of epithelial tissue in the mammary glands.
amino acid
(am-ee-no) [Gk. Ammon, referring to the Egyptian sun god, near whose temple ammonium salts were first prepared from camel dung]
An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.
amino group
A functional group that consists of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of +1.
aminoacyl—tRNA synthetases
A family of enzymes, at least one for each amino acid, that catalyze the attachment of an amino acid to its specific tRNA molecule.
ammonification
The process by which decomposers break down proteins and amino acids, releasing the excess nitrogen in the form of ammonia (NH3) or ammonium ion (NH4+).
amniocentesis
(am-nee-oh-sen-tee-sis)
A technique for determining genetic abnormalities in a fetus by the presence of certain chemicals or defective fetal cells in the amniotic fluid, obtained by aspiration from a needle inserted into the uterus.
amnion
(am-nee-on) [Gk. dim. of amnos, lamb]
The innermost of four extraembryonic membranes; encloses a fluid-filled sac in which the embryo is suspended.
amniote
A vertebrate possessing an amnion surrounding the embryo; reptiles, birds, and mammals are amniotes.
amniotic egg
A shelled, water-retaining egg that enables reptiles, birds, and egg-laying mammals to complete their life cycles on dry land.
amoeboid
[Gk. amoibe, change]
Moving or feeding by means of pseudopodia (temporary cytoplasmic protrusions from the cell body).
AMP
Abbreviation of adenosine monophosphate.
Amphibia
The vertebrate class of amphibians, represented by frogs, salamanders, and caecilians.
amphipathic molecule
A molecule that has both a hydrophilic region and a hydrophobic region.
anabolic steroids
Synthetic chemical variants of the male sex hormone testosterone; they produce increased muscle mass but also suppress testosterone production, leading to shrinkage of the testes, growth of the breasts, and premature baldness; long-term use increases the risk of kidney and liver damage and of liver cancer.
anabolism
[Gk. ana, up + -bolism (as in metabolism)]
Within a cell or organism, the sum of all biosynthetic reactions (that is, chemical reactions in which larger molecules are formed from smaller ones).
anaerobic
an-air-oh-bik) [Gk. an, without + aer, air + bios, life]
Lacking oxygen; referring to an organism, environment, or cellular process that lacks oxygen and may be poisoned by it.
anagenesis
(an-uh-jen-eh-sis)
A pattern of evolutionary change involving the transformation of an entire population, sometimes to a state different enough from the ancestral population to justify renaming it as a separate species; also called phyletic evolution.
analogy
The similarity of structure between two species that are not closely related; attributable to convergent evolution.
analogous
[Gk. analogos, proportionate]
Applied to structures similar in function but different in evolutionary origin, such as the wing of a bird and the wing of an insect.
anaphase
(anna-phase) [Gk. ana, up + phasis, form]
The third stage of mitosis, beginning when the centromeres of duplicated chromosomes divide and sister chromotids separate from each other, and ending when a complete set of daughter chromosomes are located at each of the two poles of the cell.
androgen
(an-droh-jens) [Gk. andros, man + genos, origin, descent]
The principal male steroid hormones, such as testosterone, which stimulate the development and maintenance of the male reproductive system and secondary sex characteristics.
aneuploidy
(an-yoo-ploy-dee)
A chromosomal aberration in which certain chromosomes are present in extra copies or are deficient in number.
angiosperm
(an-jee-o-sperms) [Gk. angeion, vessel + sperma, seed]
A flowering plant, which forms seeds inside a protective chamber called an ovary.
anion
(an-eye-on)
A negatively charged ion.
annual
[L. annus, year]
A plant that completes its entire life cycle in a single year or growing season.
antennae
Long, paired sensory appendages on the head of many arthropods.
anterior
[L. ante, before, toward, in front of]
Referring to the head end of a bilaterally symmetrical animal.
anther
[Gk. anthos, flower]
The terminal pollen sac of a stamen, inside which pollen grains with male gametes form in the flower of an angiosperm.
antheridium pl. antheridia
In plants, the male gametangium, a moist chamber in which gametes develop.
anthocyanin
Natural water-soluble pigments of blue, purple or red which are dissolved in the cell-sap vacuole of plant cells.
anthropoid
[Gk. anthropos, man, human]
A higher primate; includes monkeys, apes, and humans.
antibiotic
[Gk. anti, against + bios, life]
A chemical that kills bacteria or inhibits their growth.
antibody
[Gk. anti, against]
An antigen-binding immunoglobulin, produced by B cells, that functions as the effector in an immune response.
anticodon
A specialized base triplet on one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule.
antidiuretic hormone (ADH)
[Gk. anti, against + diurgos, thoroughly wet + hormaein, to excite]
A hormone important in osmoregulation.
antigen
(an-teh-jen) [Gk. anti, against + genos, origin, descent]
A foreign macromolecule that does not belong to the host organism and that elicits an immune response.
aorta
(a-ore-ta) [Gk. aeirein, to lift, heave]
The major artery in blood-circulating systems; the aorta sends blood to the other body tissues.
aphotic zone
(ay-foe-tik) [Gk. aeirein, to lift, heave]
The part of the ocean beneath the photic zone, where light does not penetrate sufficiently for photosynthesis to occur.
apical dominance
(ay-pik-ul) [L. apex, top]
Concentration of growth at the tip of a plant shoot, where a terminal bud partially inhibits axillary bud growth.
apical meristem
(ay-pik-ul mare-eh-stem) [L. apex, top + Gk. meristos, divided]
Embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length.
apomorphic character
(ap-oh-more-fik)
A derived phenotypic character, or homology, that evolved after a branch diverged from a phylogenetic tree.
apoplast
(ap-oh-plast)
In plants, the nonliving continuum formed by the extracellular pathway provided by the continuous matrix of cell walls.
apoptosis
Programmed cell death brought about by signals that trigger the activation of a cascade of "suicide" proteins in the cells destined to die.
aposematic coloration
(ap-oh-so-mat-ik)
The bright coloration of animals with effective physical or chemical defenses that acts as a warning to predators.
aquaporin
A transport protein in the plasma membranes of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis).
aqueous solution
(ay-kwee-us)
A solution in which water is the solvent.
arboreal
[L. arbor, tree]
Tree-dwelling.
Archaea
One of two prokaryotic domains, the other being the Bacteria.
archegonium pl. archegonia
(ar-kih-go-nee-um) [Gk. archegonos, first of a race]
In plants, the female gametangium, a moist chamber in which gametes develop.
archenteron
(ark-en-ter-on) [Gk. arch, first, or main + enteron, gut]
The endoderm-lined cavity, formed during the gastrulation process, that develops into the digestive tract of an animal.
Archezoa
Primitive eukaryotic group that includes diplomonads, such as Giardia; some systematists assign kingdom status to archezoans.
arteriole
A very small artery. See also artery.
artery
A vessel that carries blood away from the heart to organs throughout the body.
arteriosclerosis
A cardiovascular disease caused by the formation of hard plaques within the arteries.
artificial selection
The selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits.
ascus pl. asci
A saclike spore capsule located at the tip of the ascocarp in dikaryotic hyphae; defining feature of the Ascomycota division of fungi.
asexual reproduction
A type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more parts.
assimilation
The energy-requiring process by which plant cells convert nitrate ions (NO3–) taken up by the roots of plants into ammonium ions (NH4+), which can then be used in the synthesis of amino acids and other nitrogenous compounds.
associative learning
The acquired ability to associate one stimulus with another; also called classical conditioning.
assortative mating
A type of nonrandom mating in which mating partners resemble each other in certain phenotypic characters.
asymmetric carbon
A carbon atom covalently bonded to four different atoms or groups of atoms.
atmospheric pressure
[Gk. atmos, vapor + sphaira, globe]
The weight of the Earth's atmosphere over a unit area of the Earth's surface.
atom
[Gk. atomos, indivisible]
The smallest unit of matter that retains the properties of an element.
atomic number
The number of protons in the nucleus of an atom, unique for each element and designated by a subscript to the left of the elemental symbol.
atomic weight
The total atomic mass, which is the mass in grams of one mole of the atom.
ATP
Abbreviation of adenosine triphosphate, the principal energy-carrying compound of the cell.
ATP synthase
A cluster of several membrane proteins found in the mitochondrial cristae (and bacterial plasma membrane) that function in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen-ion concentration gradient to make ATP. ATP synthases provide a port through which hydrogen ions diffuse into the matrix of a mitrochondrion.
atrioventricular node
[L. atrium, yard, court, hall + ventriculus, the stomach + nodus, knot]
A group of slow-conducting fibers in the atrium of the vertebrate heart that are stimulated by impulses originating in the sinoatrial node (the pacemaker) and that conduct impulses to the bundle of His, a group of fibers that stimulate contraction of the ventricles.
atrioventricular valve
A valve in the heart between each atrium and ventricle that prevents a backflow of blood when the ventricles contract.
atrium pl. atria
(a-tree-um) [L. yard, court, hall]
A chamber that receives blood returning to the vertebrate heart.
autogenesis model
According to this model, eukaryotic cells evolved by the specialization of internal membranes originally derived from prokaryotic plasma membranes.
autoimmune disease
An immunological disorder in which the immune system turns against itself.
autonomic nervous system
(awt-uh-nahm-ik) [Gk. autos, self + nomos, usage, law]
A subdivision of the motor nervous system of vertebrates that regulates the internal environment; consists of the sympathetic and parasympathetic divisions.
autopolyploid
(aw-toe-pol-ee-ploid)
A type of polyploid species resulting from one species doubling its chromosome number to become tetraploid, which may self-fertilize or mate with other tetraploids.
autosome
(awtuh-some) [Gk. autos, self + soma, body]
A chromosome that is not directly involved in determining sex, as opposed to the sex chromosomes.
autotroph
(aw-toh-trohf) [Gk. autos, self + trophos, feeder]
An organism that obtains organic food molecules without eating other organisms. Autotrophs use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones.
auxin
(awk-sins) [Gk. auxein, to increase + in, of, or belonging to]
A class of plant hormones, including indoleacetic acid (IAA), having a variety of effects, such as phototropic response through the stimulation of cell elongation, stimulation of secondary growth, and the development of leaf traces and fruit.
auxotroph
(awk-soh-trohf)
A nutritional mutant that is unable to synthesize and that cannot grow on media lacking certain essential molecules normally synthesized by wild-type strains of the same species.
Aves
The vertebrate class of birds, characterized by feathers and other flight adaptations.
axillary bud
[Gk. axilla, armpit]
An embryonic shoot present in the angle formed by a leaf and stem.
axis
An imaginary line passing through a body or organ around which parts are symmetrically aligned.
axon
(aks-on) [Gk. axon, axle]
A typically long extension, or process, from a neuron that carries nerve impulses away from the cell body toward target cells.

ALL ABOUT CHEMISTRY.

DEFINITION OF CHEMISTRY:

Chemistry, a branch of physical science, is the study of the composition, structure, properties and change of matter.Everything you hear, see, smell, taste, and touch involves chemistry and chemicals (matter).

A
    absolute zero - a theoretical condition concerning a system at zero Kelvin where a system does not emit or absorb energy (all atoms are at rest)
    accuracy - how close a value is to the actual or true value; also see precision
    acid - a compound that, when dissolved in water, gives a pH of less than 7.0 or a compound that donates a hydrogen ion
    acid anhydride - a compound with two acyl groups bound to a single oxygen atom
    acid dissociation constant - an equilibrium constant for the dissociation of a weak acid
    actinides - the fifteen chemical elements that are between actinium (89) and lawrencium (103)
    activated complex - a structure that forms because of a collision between molecules while new bonds are formed
    activation energy - the minimum energy that must be input to a chemical system
    activity series
    actual yield
    addition reaction - within organic chemistry, when two or more molecules combine to make a larger one
    aeration - the mixing of air into a liquid or solid
    alkali metals - the metals of Group 1 on the periodic table
    alkaline earth metals - the metals of Group 2 on the periodic table
    allomer - a substance that has different composition than another, but has the same crystalline structure
    allotropy - elements that can have different structures (and therefore different forms), such as Carbon (diamonds, graphite, and fullerene)
    anion - negatively charge ions
    anode - the positive side of a dry cell battery or a cell
    aromaticity - chemical property of conjugated rings that results in unusual stability. See also benzene.
    atom - a chemical element in its smallest form, and is made up of neutrons and protons within the nucleus and electrons circling the nucleus
    atomic mass unit
    atomic number - the number representing an element which corresponds with the number of protons within the nucleus
    atomic orbital - the region where the electron of the atom may be found
    atomic radius
    average atomic mass
    Avogadro's law
    Avogadro's number - is the number of particles in a mole of a substance ( 6.02x10^23 )

B

    barometer - a device used to measure the pressure in the atmosphere
    base - a substance that accepts a proton and has a high pH; a common example is sodium hydroxide (NaOH)
    biochemistry - the chemistry of organisms
    boiling - the phase transition of liquid vaporizing
    boiling point - the temperature in which the substance starts to boil
    boiling-point elevation - the process where the boiling point is elevated by adding a substance
    bond - the attraction and repulsion between atoms and molecules that is a cornerstone of chemistry
    Boyle's law -
    Brønsted-Lowrey acid - A chemical species that donates a proton
    Brønsted–Lowry acid–base reaction -
    Brønsted-Lowrey base - A chemical species that accepts a proton
    buffered solution - An aqueous solution consisting of a weak acid and its conjugate base or a weak base and its conjugate acid that resists changes in pH when strong acids or bases are added
    burette (also buret) - glassware used to dispense specific amounts of liquid when precision is necessary (e.g. titration and resource dependent reactions)

C
An example of combustion

    catalyst - a chemical compound used to change the rate (either to speed up or slow down) of a reaction, but is regenerated at the end of the reaction.
    cation - positively charged ion
    centrifuge - equipment used to separate substances based on density by rotating the tubes around a centred axis
    cell potential - the force in a galvanic cell that pulls electron through reducing agent to oxidizing agent
    chemical Law - certain rules that pertain to the laws of nature and chemistry - examples
    chemical reaction - the change of one or more substances into another or multiple substances
    colloid - mixture of evenly dispersed substances, such as many milks
    combustion - an exothermic reaction between an oxidant and fuel with heat and often light
    compound - a substance that is made up of two or more chemically bonded elements
    condensation - the phase change from gas to liquid
    conductor - material that allows electric flow more freely
    covalent bond - chemical bond that involves sharing electrons
    crystal - a solid that is packed with ions, molecules or atoms in an orderly fashion
    cuvette - glassware used in spectroscopic experiments. It is usually made of plastic, glass or quartz and should be as clean and clear as possible

D

    deionization - the removal of ions, and in water's case mineral ions such as sodium, iron and calcium
    deliquescence - substances that absorb water from the atmosphere to form liquid solutions
    deposition - settling of particles within a solution or mixture
    dipole - electric or magnetic separation of charge
    dipole moment - the polarity of a polar covalent bond
    dissolution or solvation - the spread of ions in a monosacharide
    double bond - sharing of two pairs of electradodes

E
Microcentrifuge or Eppendorf tube with Coomassie Blue solution

    earth metal - see alkaline earth metal
    electrolyte - a solution that conducts a certain amount of current and can be split categorically as weak and strong electrlytes
    electrochemical cell - using a chemical reaction's current, electromotive force is made
    electromagnetic radiation - a type of wave that can go through vacuums as well as material and classified as a self-propagating wave
    electromagnetism - fields that have electric charge and electric properties that change the way that particles move and interact
    electromotive force - a device that gains energy as electric charges pass through it
    electron - a subatomic particle with a net charge that is negative
    electron shells - an orbital around the atom's nucleus that has a fixed number electrons (usually two or eight)
    electric charge - a measured property (coulombs) that determine electromagnetic interaction
    element - an atom that is defined by its atomic number
    energy - A system's ability to do work
    enthalpy - measure of the total energy of a thermodynamic system (usually symbolized as H)
    entropy - the amount of energy not available for work in a closed thermodynamic system (usually symbolized as S)
    enzyme - a protein that speeds up (catalyses) a reaction
    Empirical Formula - also called the simplest formula, gives the simplest whole -number ratio of atoms of each element present in a compound.
    eppendorf tube - generalized and trademarked term used for a type of tube; see microcentrifuge

F

    freezing - phase transition from liquid to solid
    Faraday constant - a unit of electrical charge widely used in electrochemistry and equal to ~ 96,500 coulombs.

    It represents 1 mol of electrons, or the Avogadro number of electrons: 6.022 × 1023 electrons. F = 96 485.339 9(24) C/mol

    Faraday's law of electrolysis - a two part law that Michael Faraday published about electrolysis
        the mass of a substance altered at an electrode during electrolysis is directly proportional to the quantity of electricity transferred at that electrode
        the mass of an elemental material altered at an electrode is directly proportional to the element's equivalent weight.
    frequency - number of cycles per unit of time. Unit: 1 hertz = 1 cycle per 1 second

G

    galvanic cell - battery made up of electrochemical with two different metals connected by salt bridge
    gas - particles that fill their container though have no definite shape or volume
    geochemistry - the chemistry of and chemical composition of the Earth
    Gibbs energy - value that indicates the spontaneity of a reaction (usually symbolized as G)

H

    halogens - Group 7 on the Periodic Table and are all non-metals
    heat - energy transferred from one system to another by thermal interaction

J

    jodium – Latin name of the halogen element iodine
    Joule - The SI unit of energy, defined as a newton-meter.

I

    indicator - a special compound added to solution that changes color depending on the acidity of the solution; different indicators have different colors and effective pH ranges
    inorganic compound - compounds that do not contain carbon, though there are exceptions (see main article)
    inorganic chemistry - a part of chemistry concerned with inorganic compounds
    International Union of Pure and Applied Chemistry (IUPAC) -
    insulator - material that resists the flow of electric current
    ion - a molecule that has gained or lost one or more electrons
    ionic bond - electrostatic attraction between oppositely charged ions
    ionization -The breaking up of a compound into separate ions.

K

    Kinetics - A sub-field of chemistry specializing in reaction rates
    Kinetic energy - The energy of an object due to its motion.

L

    lanthanides - Elements 57 through 71
    lattice - Unique arrangement of atoms or molecules in a crystalline liquid or solid.
    Laws of thermodynamics
    liquid - A state of matter which takes the shape of its container
    light - Portion of the electromagnetic spectrum which is visible to the naked eye. Also called "visible light."
    London dispersion forces - A weak intermolecular force
    Law of Motion -A object in motion stay in motion an object in rest stays in rest unless a unbalanced force acts on it.

M
This is a molecule, which is one of the key components within chemistry

    Metal - Chemical element that is a good conductor of both electricity and heat and forms cations and ionic bonds with non-metals.
    melting - The phase change from a solid to a liquid
    metalloid - A substance possessing both the properties of metals and non-metals
    methylene blue - a heterocyclic aromatic chemical compound with the molecular formula C16H18N3SCl
    microcentrifuge - a small plastic container that is used to store small amounts of liquid
    mole - abbreviated mol - a measurement of an amount of substance; a single mole contains approximately 6.022×1023 units or entities
        a mole of water contains 6.022×1023 H2O molecules
    molecule - a chemically bonded number of atoms that are electrically neutral
    molecular orbital - region where an electron can be found in a molecule (as opposed to an atom)

N

    neat - conditions with a liquid reagent or gas performed with no added solvent or cosolvent
    neutron - a neutral unit or subatomic particle that has no net charge
    neutrino - a particle that can travel at speeds close to the speed of light and are created as a result of radioactive decay
    nucleus - the centre of an atom made up of neutrons and protons, with a net positive charge
    noble gases - group 18 elements, those whose outer electron shell is filled
    non-metal - an element which is not metallic
    nuclear - of or pertaining to the atomic nucleus
    nuclear magnetic resonance spectroscopy - technique that exploits the magnetic properties of certain nuclei, useful for identifying unknown compounds
    number density – a measure of concentration of countable objects (atoms, molecules, etc.) in space; number per volume

O

    orbital - may refer to either an atomic orbital or a molecular orbital
    organic compound - compounds that contain carbon
    organic chemistry - a part of chemistry concerned with organic compounds

P

    pH - the measure of acidity (or basicity) of a solution
    plasma - state of matter similar to gas in which a certain portion of the particles are ionized
    other metal - metallic elements in the p-block, characterized by having a combination of relatively low melting points (all less than 950 K) and relatively high electronegativity values (all more than 1.6, revised Pauling)
    potential energy - energy stored in a body or in a system due to its position in a force field or due to its configuration
    precipitate - formation of a solid in a solution or inside another solid during a chemical reaction or by diffusion in a solid
    precision - How close the results of multiple experimental trials are. See also accuracy.
    photon - a carrier of electromagnetic radiation of all wavelength (such as gamma rays and radio waves)
    proton - a positive unit or subatomic particle that has a positive charge
    protonation - the addition of a proton (H+) to an atom, molecule, or ion

Q

    Quantum mechanics - the study of how atoms, molecules, subatomic particles, etc. behave and are structured
    quarks - elementary particle and a fundamental constituent of matter

R

    radiation - energy in the form of waves or subatomic particles when there is a change from high energy to low energy states
    radioactive decay - the process of an unstable atomic nucleus losing energy by emitting radiation
    Raoult's law -
    reactivity series -
    reagent -

S

    s-block elements - Group 1 and 2 elements (alkali and alkaline metals), which includes Hydrogen and Helium
    salts - ionic compounds composed of anions and cations
    salt bridge - devices used to connection reduction with oxidation half-cells in an electrochemical cell
    saline solution - general term for NaCl in water
    Schrödinger equation - quantum state equation which represents the behaviour of an election around an atom
    semiconductor - an electrically conductive solid that is between a conductor and an insulator
    single bond - sharing of one pair of electrons
    sol - a suspension of solid particles in liquid. Artificial examples include sol-gels.
    solid - one of the states of matter, where the molecules are packed close together, there is a resistance of movement/deformation and volume change; see Young's modulus
    solute - the part of the solution that is mixed into the solvent (NaCl in saline water)
    solution - homogeneous mixture made up of multiple substances. It is made up of solutes and solvents.
    solvent - the part of the solution that dissolves the solute (H2O in saline water)
    spectroscopy - study of radiation and matter, such as X-ray absorption and emission spectroscopy
    speed of light - the speed of anything that has zero rest mass (Energyrest = mc² where m is the mass and c is the speed of light)
    Standard conditions for temperature and pressure or SATP - a standardisation used in order compare experimental results (25 °C and 100.000 kPa)
    state of matter - matter having a homogeneous, macroscopic phase; gas, plasma, liquid, and solid are the most well known (in increasing concentration)
    sublimation - a phase transition from solid to limewater fuel or gas
    subatomic particles - particles that are smaller than an atom; examples are protons, neutrons and electrons
    substance - material with definite chemical composition

T
Phase diagram showing the triple and critical points of a substance

    talc - a mineral representing the one on the Mohs Scale and composed of hydrated magnesium silicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2
    temperature - the average energy of microscopic motions of particles
    theoretical yield - see yield
    theory - a model describing the nature of a phenomenon
    thermal conductivity - a property of a material to conduct heat (often noted as k)
    thermochemistry - the study of absorption/release of heat within a chemical reaction
    thermodynamics - the study of the effects of changing temperature, volume or pressure (or work, heat, and energy) on a macroscopic scale
    thermodynamic stability - when a system is in its lowest energy state with its environment (equilibrium)
    thermometer - device that measures the average energy of a system
    titration - the process of titrating one solution with another, also called volumetric analysis
    torr - a unit to measure pressure (1 Torr is equivalent to 133.322 Pa or 1.3158×10−3 atm)
    transition metal - elements that have incomplete d sub-shells, but also may be referred to as the d-block elements
    transuranic element - element with atomic number greater than 92; none of the transuranic elements are stable
    triple bond - the sharing of three pairs of electrons within a covalent bond (example N2)
    triple point - the place where temperature and pressure of three phases are the same (Water has a special phase diagram)
    Tyndall effect - the effect of light scattering by colloidal (mixture where one substance is dispersed evenly through another) or suspended particles

U

    UN number - a four digit code used to note hazardous and flammable substances
    uncertainty - a characteristic that any measurement that involves estimation of any amount cannot be exactly reproducible
    Uncertainty principle - knowing the location of a particle makes the momentum uncertain, while knowing the momentum of a particle makes the location uncertain
    unit cell - the smallest repeating unit of a lattice
    unit factor - statements used in converting between units
    universal or ideal gas constant - proportionality constant in the ideal gas law (0.08206 L·atm/(K·mol))

V

    valence electron - the outermost electrons of an atom, which are located in electron shells
    Valence bond theory - a theory explaining the chemical bonding within molecules by discussing valencies, the number of chemical bonds formed by an atom
    van der Waals force - one of the forces (attraction/repulsion) between molecules
    van 't Hoff factor - ratio of moles of particles in solution to moles of solute dissolved
    vapor - when a substance is below the critical temperature while in the gas phase
    vapour pressure - pressure of vapour over a liquid at equilibrium
    vaporization - phase change from liquid to gas
    viscosity - the resistance of a liquid to flow (oil)
    volt - one joule of work per coulomb - the unit of electrical potential transferred
    voltmeter - instrument that measures the cell potential
    volumetric analysis - see titration

W

    water - H2O - a chemical substance, a major part of cells and Earth, and covalently bonded
    wave function - a function describing the electron's position in a three-dimensional space
    work - the amount of force over distance and is in terms of joules (energy)

X

    X-ray - form of ionizing, electromagnetic radiation, between gamma and UV rays
    X-ray diffraction - a method for establishing structures of crystalline solids using singe wavelength X-rays and looking at diffraction pattern
    X-ray photoelectron spectroscopy - a spectroscopic technique to measure composition of a material

Y

    yield - the amount of product produced during a chemical reaction

Z

    zone melting - a way to remove impurities from an element by melting it and slowly travel down an ingot (cast)
    Zwitterion - is a chemical compound whose net charge is zero and hence is electrically neutral. But there are some positive and negative charges in it, due to the formal charge, owing to the partial charges of its constituent atoms.
 

Chemical Formula and Equations - Subscripts
A chemical formula or equation shows the symbols of the elements in the compound and the ratio of the elements to one another. If a substance contains more than one atom of a particular element, this quantity is indicated in chemical formulas or equations using a subscript number after the element symbol. The subscript number refers only to the element it immediately follows. For example, the chemical formula for water is H₂O which indicates that 2 atoms of Hydrogen combines with 1 atom of oxygen.

How to write a Chemical Formula or Equation using SubscriptsTo type or write a subscript for a chemical formula or equation just follow these simple instructions:

• Type in the formula or equation for example H2O
• Highlight the number
• Click Format
• Select Font... Decrease the font size of the number
• Under the heading Effects tick the Subscript Box
• The formula will now show the equation with the number in subscript - H₂O

Chemical Formula and Equations

Chemical Formula and Equations - Examples and Meanings of SubscriptsFor example, the chemical formula for water is H2O which indicates that 2 atoms of Hydrogen combines with 1 atom of oxygen. The chemical formula for sodium chloride (Salt) is NaCl indicating that one atom of sodium combines with one atom of chlorine in a one-to-one ratio. Subscripts are added, following the element symbol, to indicate that the number of atoms of that element in the compound if it is greater than one. For example, the formula for magnesium bromide MgBr2 which indicates that one magnesium atom combines with two bromine atoms.

Meanings and Examples of Chemical Formula and EquationsThe following examples of Chemical Formula and Equations explain their meaning.

Example of Chemical Formula for Salt (Sodium Chloride) - NaCl

NaCl

Symbol Na indicates the element Sodium
Symbol Cl indicates the element Chlorine
No subscripts indicate only 1 atom for each element              

Example of Chemical Formula for Water - H₂O

H₂O

Symbol H indicates the element Hydrogen
Symbol O indicates the element Oxygen
Subscript indicates 2 atoms of Hydrogen

Chemical Formula and Equations - Common Chemical Formula List
The following list of Chemical Formula and Equations shows some of the most common chemical formulas.

Common Chemical Formula List
Na	Sodium
H2O	Water
C6H12O6	Glucose
C2H6O	Alcohol
CaSO4	Sulfate Group
H2S	Hydrogen Sulfide
NaCl	Salt
O2	Oxygen
C2H6O	Ethanol
C2H4O2	Vinegar
NH3	Ammonia
Mg	Magnesium
C2H4O2	Acetic Acid
C4H10	Butane
NO3−	Nitrate
Cu	Copper
N2	Nitrogen
CO2	Carbon Dioxide
H2SO4	Sulfuric Acid
CH4	Methane
C12H22O11	Sucrose
C3H8	Propane
NaHCO3	Baking Soda
F	Fluoride
F2	Fluoride
H2O2	Peroxide
C8H10N4O2	Caffeine
NaCl	Sodium Chloride
C9H8O4	Aspirin
HCl	Hydrochloric Acid
Zn(NO3)2	Zinc
CO	Carbon Monoxide
NaOH	Sodium Hydroxide
NaCN	Sodium Cyanide
Ca(CN)2	Calcium Cyanide
Au	Gold
I	Iodine
Sn	Tin
C6H6	Benzene
H2S	Hydrogen Sulfide
CH3COCH3	Acetone
H3PO4	Phosphoric Acid
C5H12	Pentane
CH3OH	Methanol
HBr	Hydrobromic Acid
H2CO3	Carbonic Acid
Ti	Titanium
NaClO	Sodium Hypochlorite
C2H6	Ethane
(NH4)2SO4	Ammonium Sulfate
C8H18	Octane
CuSO4	Copper Sulfate
C27H46O	Cholesterol
C7H6O2	Benzoic Acid
H2SO3	Sulfurous Acid
C6H12O6	Galactose
C6H8O6	Ascorbic Acid
CO2	Dry Ice
NaNO3	Sodium Nitrate
CaO	Calcium Oxide
HIO3	Iodic Acid
C3H6O3	Lactic Acid
MgBr2	Lactic Acid
H2O	Water Vapor
No Formula	Oxide
C	Carbon
H	Hydrogen
CnH2nOn	Sugar
O4S2-	Sulfate
N2O	Nitrogen
C6H8O7	Citric Acid
C8H18	Octane
C10H16O	Camphor
AgI	Silver Oxide
As4O3	Arsenic Trioxide
Au2O3	Gold Trioxide
Au2S	Gold Sulfide
Br2	Bromine
Al2O3	Aluminium foil
Common Chemical Formulas List