Absolute Zero
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********************************{ Glossary }***********************************
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Absolute Temperature:
A scale for measuring temperature that is obtained by adding algebraically 273
to degrees centigrade.
Absolute Zero:
The temperature,273 degrees below the zero of the centigrade scale,at which all
molecular motion ceases.
Acid:
A compound which yields hydrogen ions in aqueous solution;a proton donor.
Addition reaction:
A reaction in which a reagent adds to a carbon-carbon double or triple bond.
Adsorption:
A process in which molecules or ions adhere to the surface of a solid.
Alkali:
A water soluble base that yields hydroxyl ions in aqueous solution.
Allotropism:
The property of certain elements of existing in more than one form,such as
oxygen and ozone.
Alpha particle:
The positively charged nucleus of the helium atom.
Anhydrous:
Without water.
Anion:
A negatively charged ion.
Anode:
The positively charged electrode of an electrolytic cell.
Atom:
The smallest unit of an element that participates in chemical change.
Atomic number:
A number,characteristic of an atom,that represents the number of protons in the
nucleus of the atom.It indicates the location of an element in the periodic
table.
Atomic weight:
The relative weight of an atom referred to carbon,whose weight has been
arbitrarily set at 12.01115.
Avogadro's law:
The law which states that equal volumes of all gases,at the same temperature
and pressure,contain the same number of molecules.
Base:
A compound which yields hydroxide ions in aqueous solution;a proton acceptor.
Beta particle:
A negative electron given off by a radioactive substance.
Binary compound:
A compound composed of two elements per molecule.
Boiling point:
The temperature at which the vapor pressure in a liquid equals the atmospheric
pressure.
Brownian movement:
The rapid oscillatory movement of small particles when suspended in water or
other liquids.
BTU:
British Thermal Unit,the quantity of heat required to raise the temperature of
one pound of water one degree Fahrenheit.It is equal to 0.252 calorie.
Buffer:
A substance that keeps the pH of a solution relatively constant in spite of the
addition of considerable amounts of acid or base.
Calorie:
A small calorie(cal.) is the amount of heat required to raise the temperature
of 1 gram of water by one degree Celsius.A large calorie(Cal.)equals 1000
calories.
Carboxyl group:
A univalent organic radical (-COOH) which is the functional group of all the
carbolic acids.
Catalyst:
A substance which speeds up,or less frequently retards,a chemical reaction,
without being changed itself.
Cathode:
The negatively charged electrode of an electrolytic cell.
Cation:
A positively charged ion.
Chemical change:
A change in which the chemical structure of a substance is changed.
Chemistry:
The science which deals with the composition and properties of substances and
their transformation from one form to another.
Colloids:
Particles which are intermediate in size between crystalloids that form true
solutions and suspensions that eventually settle.
Combining weight:
The weight of an element which will combine with 8 grams of oxygen,or 1.008
grams of hydrogen.
Combustion:
Rapid oxidation accompanied by evolution of heat and usually light.
Compound:
A substance composed of two or more elements united chemically in definite
proportions by weight.
Covalence:
The combining of atoms by means of the sharing of electrons.
Crystalloids:
Substances which,when dissolved in liquid,will diffuse through a semipermeable
membrane.
Dehydration:
The removal of water from a substance.
Deliquescence:
The process whereby certain substances absorb sufficient water from the atmos-
phere to dissolve themselves.
Denaturation:
The process of altering the structure of a protein by physical or chemical
means.
Density:
Mass per unit volume.
Deoxygenation:
The process of removing water from a compound.
Deuterium:
An isotope of hydrogen having twice the mass of ordinary hydrogen.
Diffusion:
The process by which one substance distributes itself uniformly through water.
Dispersion:
Colloidal particles suspended in a liquid medium.
Distillation:
The evaporation of a liquid and the condensation of it's vapor.
Efflorescence:
The spontaneous loss of water by a substance when exposed to air.
Electrolysis:
The decomposition of a chemical compound by an electrical current.
Electrolyte:
A substance which will conduct an electrical current when in solution or melted
Electron:
An atomic particle carrying a unit charge of negative electricity,having a mass
of 1/1837 of that of a proton.
Electrophoresis:
The migration of colloidal particles dispersed in a fluid,under the influence
of an electric field.
Electrovalence:
The valence as determined by the electrons lost or gained by the elements
reacting to form a compound.
Element:
One of the basic fundamental forms of matter that cannot be separated into
simpler substances by ordinary chemical means.
Emulsion:
A colloidal dispersion of a liquid in another liquid.
Endothermic reaction:
A chemical change in which heat is absorbed.
Energy:
The ability to do work.
Equilibrium:
A state existing in a reversable reaction when the rates of the forward and
reverse reactions are equal and the concentrations of the reactants and
products are equal.
Ester:
An organic compound formed by the reaction between an acid and an alcohol.
Exothermic reaction:
A chemical change in which heat is liberated.
Filtration:
The process of separating suspended particles from a liquid by means of a
porous medium.
Fission:
The disintegration of the nucleus of a heavy atom with the liberation of large
amounts of energy.
Formula:
An expression of the constituents of a compound by symbols.
Gamma ray:
Similar to X-rays,forming part of the radiation of a radioactive substance.
Gel:
A semi-rigid colloid.
Gram-atomic weight:
One atomic weight of an element expressed in grams.
Gram-molecular weight:
One molecular weight of a compound expressed in grams.
Half-life:
The length of time required for one-half of a radioactive substance to disinte-
grate.
Halide:
A compound composed of two elements,one of which is a halogen.
Halogens:
A family of elements consisting of flourine,chlorine,bromine and iodine.
Heterocyclic compounds:
Cyclic compounds in which the ring system of the molecule contains other
elements than carbon.
Hydrate:
A compound containing water of crystallization.
Hydride:
A compound containing a negatively charged hydrogen,as in sodium hydride(Na-H).
Hydrocarbons:
Organic compounds containing hydrogen and carbon only.
Hydrogenation:
A chemical reaction in which hydrogen is added to a compound.
Hydrolysis:
Chemical decomposition by which a compound is resolved into other compounds by
taking up the elements of hydrogen.
Hypertonic solution:
A solution of higher osmotic pressure than another with which it is compared.
Immiscible:
Incapable of being mixed,as oil and water.
Indicator:
A compound which changes color with changes in the hydrogen ion concentration
(pH)of a solution.
Iodine number:
The number of grams of iodine required to saturate 100 grams of fat.
Ion:
An electrically charged atom or radical.
Ionization:
The separation of an electrolyte into charged ions in solution.
Isoelectric point:
The pH at which a substance is electrically neutral or at it's minimum ioniza-
ation.
Isomers:
Compounds which have the same molecular formula but different structural
formulas.
Isotonic solution:
A solution having the same osmotic pressure as another with which it is
compared.
Isotopes:
Atoms of the same element having the same atomic number but having different
atomic weights.
Ketone:
An organic compound containing the carbonyl group attached to two organic
radicals.
Kindling temperature:
The lowest temperature at which a substance bursts into flame.
Kinetic energy:
Energy in motion.
Latent heat:
The heat absorbed in the changing of a substance from solid to liquid,or from a
liquid to a gas.
Matter:
Anything which occupies space and has mass.
Miscible:
Capable of being mixed.
Mixture:
An aggregate of two or more substances which are not chemically combined and
which exist in no fixed proportion to one another.
Molal solution:
A solution containing one mole of a solute in 1,000 grams of solute.
Molar solution:
A solution which contains 1 gram-molecular weight of solute in one liter of
solution.
Mole:
The molecular weight of a substance expressed in grams.
Molecular weight:
The sum of the atomic weights of all the atoms in a molecule.
Molecule:
The smallest particle of a compound that can exist independently.
Nascent:
The condition of an element that has just been released in the monatomic state
in a chemical reaction.
Neutron:
A neutral particle existing in the nucleus of an atom.
Noble gases:
A family of elements consisting of helium,neon,argon,krypton,xenon and radon.
Nonelectrolyte:
A compound whose water solution does not conduct an electric current.
Normal solution:
A solution which contains 1 gram-equivalent weight of a solute in 21 liters of
solution.
Nucleic acid:
An organic compound composed of phosphoric acid,ribose or deoxyribose,and
purine and pyride bases.
Nucleus:
The positively charged center of the atom containing protons and neutrons.
Osmosis:
The passage of fluid from a less concentrated solution to a more concentrated
solution through a semipermeable membrane.
Oxidation:
Combination of a substance with oxygen;the increase in valence toward the
positive;the loss of electrons.
Oxide:
A compound of oxygen and some other element.
Periodic law:
The law that the properties of the elements are periodic functions of their
atomic numbers.
Periodic table:
A table illustrating the periodic system in which the chemical elements
arranged in the order of their atomic numbers are shown in related groups.
pH:
A symbol denoting the algorithm of the reciprocal of hydrogen ion concentration
Physical change:
A change in the condition or state of a substance;it's composition is not
altered.
Potential energy:
Energy that is due to position and not of motion;stored energy.
Precipitate:
An insoluble liquid that separates from solution.
Protein:
A substance of high molecular weight composed of carbon,hydrogen,nitrogen,and
sometimes sulphur or iodine,that yields upon hydrolysis amino acids or their
derivatives.
Proton:
A subatomic particle carrying a unit of positive charge.
Radical:
A group of atoms that behave as a unit in a chemical reaction.
Radioactivity:
The spontaneous disintegration of an atom,with the emission of alpha.beta,and
gamma rays.
Radioisotope:
A radioactive isotope,often used as a tracer in scientific research.
Reduction:
The removal of oxygen from a compound;the gain of electrons by a substance or a
decrease in it's valence.
Salt:
A compound consisting of a positive ion other than hydrogen and a negative ion
other than the hydroxyle ion;the product of an acid with a base.
Saturated solution:
A solution that contains all the solute that it can hold at a given temperature
and pressure.
Semipermeable membrane:
A membrane that allows water and crystalloids to pass through but holds back
colloids.
Solute:
A substance dissolved in a solvent.
Solution:
A homogeneous mixture of two or more substances.
Solvent:
A substance in which a solute is dissolved.
Specific gravity:
The ratio of the weight of a given volume of a substance to the weight of an
equal volume of water.
Specific heat:
The quantity of heat in calories required to raise the temperature of one gram
of a substance one degree Celsius.
Spontaneous combustion:
The ignition of a substance as the result of the accumulated heat of slow
oxidation.
Structural formula:
A formula which shows the arrangement of the atoms in a molecule.
Substitution reaction:
A chemical reaction in which one or more elements or radicals in a compound are
replaced by other elements or radicals.
Suspension:
A system consisting of small particles dispersed in a liquid.The particles will
settle out slowly upon standing.
Synersis:
The shrinking of a gel,with the expulsion of water or other liquid from it.
Synthesis:
The construction of a compound by the union of elements or simple compounds.
Tincture:
A solution of a medicinal substance in alcohol.
Titration:
The process of determining the quantity of a substance in a solution by adding
a measured volume of a standard solution until the desired reaction has been
affected.
Transmutation:
The conversion of one element into another in a nuclear reaction.
Tyndall effect:
The reflection of a beam of light by the dispersed particles of a colloidal
solution,making visible the path of the light.
Unsaturated compounds:
Organic compounds containing double or triple bonds and are capable of forming
addition products.
Unsaturated solution:
A solution containing less solute than the amount needed to make a saturated
solution.
Valence:
A number that represents the combining power of an element or radical.
Valence electrons:
The electrons located in the outermost shell of an atom.
Water of crystallization:
Water present in the crystal of a hydrate.
Zwitterion:
A dipolar ion carrying both a positive and a negative charge.
********************************{ Glossary }***********************************
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Absolute Temperature:
A scale for measuring temperature that is obtained by adding algebraically 273
to degrees centigrade.
Absolute Zero:
The temperature,273 degrees below the zero of the centigrade scale,at which all
molecular motion ceases.
Acid:
A compound which yields hydrogen ions in aqueous solution;a proton donor.
Addition reaction:
A reaction in which a reagent adds to a carbon-carbon double or triple bond.
Adsorption:
A process in which molecules or ions adhere to the surface of a solid.
Alkali:
A water soluble base that yields hydroxyl ions in aqueous solution.
Allotropism:
The property of certain elements of existing in more than one form,such as
oxygen and ozone.
Alpha particle:
The positively charged nucleus of the helium atom.
Anhydrous:
Without water.
Anion:
A negatively charged ion.
Anode:
The positively charged electrode of an electrolytic cell.
Atom:
The smallest unit of an element that participates in chemical change.
Atomic number:
A number,characteristic of an atom,that represents the number of protons in the
nucleus of the atom.It indicates the location of an element in the periodic
table.
Atomic weight:
The relative weight of an atom referred to carbon,whose weight has been
arbitrarily set at 12.01115.
Avogadro's law:
The law which states that equal volumes of all gases,at the same temperature
and pressure,contain the same number of molecules.
Base:
A compound which yields hydroxide ions in aqueous solution;a proton acceptor.
Beta particle:
A negative electron given off by a radioactive substance.
Binary compound:
A compound composed of two elements per molecule.
Boiling point:
The temperature at which the vapor pressure in a liquid equals the atmospheric
pressure.
Brownian movement:
The rapid oscillatory movement of small particles when suspended in water or
other liquids.
BTU:
British Thermal Unit,the quantity of heat required to raise the temperature of
one pound of water one degree Fahrenheit.It is equal to 0.252 calorie.
Buffer:
A substance that keeps the pH of a solution relatively constant in spite of the
addition of considerable amounts of acid or base.
Calorie:
A small calorie(cal.) is the amount of heat required to raise the temperature
of 1 gram of water by one degree Celsius.A large calorie(Cal.)equals 1000
calories.
Carboxyl group:
A univalent organic radical (-COOH) which is the functional group of all the
carbolic acids.
Catalyst:
A substance which speeds up,or less frequently retards,a chemical reaction,
without being changed itself.
Cathode:
The negatively charged electrode of an electrolytic cell.
Cation:
A positively charged ion.
Chemical change:
A change in which the chemical structure of a substance is changed.
Chemistry:
The science which deals with the composition and properties of substances and
their transformation from one form to another.
Colloids:
Particles which are intermediate in size between crystalloids that form true
solutions and suspensions that eventually settle.
Combining weight:
The weight of an element which will combine with 8 grams of oxygen,or 1.008
grams of hydrogen.
Combustion:
Rapid oxidation accompanied by evolution of heat and usually light.
Compound:
A substance composed of two or more elements united chemically in definite
proportions by weight.
Covalence:
The combining of atoms by means of the sharing of electrons.
Crystalloids:
Substances which,when dissolved in liquid,will diffuse through a semipermeable
membrane.
Dehydration:
The removal of water from a substance.
Deliquescence:
The process whereby certain substances absorb sufficient water from the atmos-
phere to dissolve themselves.
Denaturation:
The process of altering the structure of a protein by physical or chemical
means.
Density:
Mass per unit volume.
Deoxygenation:
The process of removing water from a compound.
Deuterium:
An isotope of hydrogen having twice the mass of ordinary hydrogen.
Diffusion:
The process by which one substance distributes itself uniformly through water.
Dispersion:
Colloidal particles suspended in a liquid medium.
Distillation:
The evaporation of a liquid and the condensation of it's vapor.
Efflorescence:
The spontaneous loss of water by a substance when exposed to air.
Electrolysis:
The decomposition of a chemical compound by an electrical current.
Electrolyte:
A substance which will conduct an electrical current when in solution or melted
Electron:
An atomic particle carrying a unit charge of negative electricity,having a mass
of 1/1837 of that of a proton.
Electrophoresis:
The migration of colloidal particles dispersed in a fluid,under the influence
of an electric field.
Electrovalence:
The valence as determined by the electrons lost or gained by the elements
reacting to form a compound.
Element:
One of the basic fundamental forms of matter that cannot be separated into
simpler substances by ordinary chemical means.
Emulsion:
A colloidal dispersion of a liquid in another liquid.
Endothermic reaction:
A chemical change in which heat is absorbed.
Energy:
The ability to do work.
Equilibrium:
A state existing in a reversable reaction when the rates of the forward and
reverse reactions are equal and the concentrations of the reactants and
products are equal.
Ester:
An organic compound formed by the reaction between an acid and an alcohol.
Exothermic reaction:
A chemical change in which heat is liberated.
Filtration:
The process of separating suspended particles from a liquid by means of a
porous medium.
Fission:
The disintegration of the nucleus of a heavy atom with the liberation of large
amounts of energy.
Formula:
An expression of the constituents of a compound by symbols.
Gamma ray:
Similar to X-rays,forming part of the radiation of a radioactive substance.
Gel:
A semi-rigid colloid.
Gram-atomic weight:
One atomic weight of an element expressed in grams.
Gram-molecular weight:
One molecular weight of a compound expressed in grams.
Half-life:
The length of time required for one-half of a radioactive substance to disinte-
grate.
Halide:
A compound composed of two elements,one of which is a halogen.
Halogens:
A family of elements consisting of flourine,chlorine,bromine and iodine.
Heterocyclic compounds:
Cyclic compounds in which the ring system of the molecule contains other
elements than carbon.
Hydrate:
A compound containing water of crystallization.
Hydride:
A compound containing a negatively charged hydrogen,as in sodium hydride(Na-H).
Hydrocarbons:
Organic compounds containing hydrogen and carbon only.
Hydrogenation:
A chemical reaction in which hydrogen is added to a compound.
Hydrolysis:
Chemical decomposition by which a compound is resolved into other compounds by
taking up the elements of hydrogen.
Hypertonic solution:
A solution of higher osmotic pressure than another with which it is compared.
Immiscible:
Incapable of being mixed,as oil and water.
Indicator:
A compound which changes color with changes in the hydrogen ion concentration
(pH)of a solution.
Iodine number:
The number of grams of iodine required to saturate 100 grams of fat.
Ion:
An electrically charged atom or radical.
Ionization:
The separation of an electrolyte into charged ions in solution.
Isoelectric point:
The pH at which a substance is electrically neutral or at it's minimum ioniza-
ation.
Isomers:
Compounds which have the same molecular formula but different structural
formulas.
Isotonic solution:
A solution having the same osmotic pressure as another with which it is
compared.
Isotopes:
Atoms of the same element having the same atomic number but having different
atomic weights.
Ketone:
An organic compound containing the carbonyl group attached to two organic
radicals.
Kindling temperature:
The lowest temperature at which a substance bursts into flame.
Kinetic energy:
Energy in motion.
Latent heat:
The heat absorbed in the changing of a substance from solid to liquid,or from a
liquid to a gas.
Matter:
Anything which occupies space and has mass.
Miscible:
Capable of being mixed.
Mixture:
An aggregate of two or more substances which are not chemically combined and
which exist in no fixed proportion to one another.
Molal solution:
A solution containing one mole of a solute in 1,000 grams of solute.
Molar solution:
A solution which contains 1 gram-molecular weight of solute in one liter of
solution.
Mole:
The molecular weight of a substance expressed in grams.
Molecular weight:
The sum of the atomic weights of all the atoms in a molecule.
Molecule:
The smallest particle of a compound that can exist independently.
Nascent:
The condition of an element that has just been released in the monatomic state
in a chemical reaction.
Neutron:
A neutral particle existing in the nucleus of an atom.
Noble gases:
A family of elements consisting of helium,neon,argon,krypton,xenon and radon.
Nonelectrolyte:
A compound whose water solution does not conduct an electric current.
Normal solution:
A solution which contains 1 gram-equivalent weight of a solute in 21 liters of
solution.
Nucleic acid:
An organic compound composed of phosphoric acid,ribose or deoxyribose,and
purine and pyride bases.
Nucleus:
The positively charged center of the atom containing protons and neutrons.
Osmosis:
The passage of fluid from a less concentrated solution to a more concentrated
solution through a semipermeable membrane.
Oxidation:
Combination of a substance with oxygen;the increase in valence toward the
positive;the loss of electrons.
Oxide:
A compound of oxygen and some other element.
Periodic law:
The law that the properties of the elements are periodic functions of their
atomic numbers.
Periodic table:
A table illustrating the periodic system in which the chemical elements
arranged in the order of their atomic numbers are shown in related groups.
pH:
A symbol denoting the algorithm of the reciprocal of hydrogen ion concentration
Physical change:
A change in the condition or state of a substance;it's composition is not
altered.
Potential energy:
Energy that is due to position and not of motion;stored energy.
Precipitate:
An insoluble liquid that separates from solution.
Protein:
A substance of high molecular weight composed of carbon,hydrogen,nitrogen,and
sometimes sulphur or iodine,that yields upon hydrolysis amino acids or their
derivatives.
Proton:
A subatomic particle carrying a unit of positive charge.
Radical:
A group of atoms that behave as a unit in a chemical reaction.
Radioactivity:
The spontaneous disintegration of an atom,with the emission of alpha.beta,and
gamma rays.
Radioisotope:
A radioactive isotope,often used as a tracer in scientific research.
Reduction:
The removal of oxygen from a compound;the gain of electrons by a substance or a
decrease in it's valence.
Salt:
A compound consisting of a positive ion other than hydrogen and a negative ion
other than the hydroxyle ion;the product of an acid with a base.
Saturated solution:
A solution that contains all the solute that it can hold at a given temperature
and pressure.
Semipermeable membrane:
A membrane that allows water and crystalloids to pass through but holds back
colloids.
Solute:
A substance dissolved in a solvent.
Solution:
A homogeneous mixture of two or more substances.
Solvent:
A substance in which a solute is dissolved.
Specific gravity:
The ratio of the weight of a given volume of a substance to the weight of an
equal volume of water.
Specific heat:
The quantity of heat in calories required to raise the temperature of one gram
of a substance one degree Celsius.
Spontaneous combustion:
The ignition of a substance as the result of the accumulated heat of slow
oxidation.
Structural formula:
A formula which shows the arrangement of the atoms in a molecule.
Substitution reaction:
A chemical reaction in which one or more elements or radicals in a compound are
replaced by other elements or radicals.
Suspension:
A system consisting of small particles dispersed in a liquid.The particles will
settle out slowly upon standing.
Synersis:
The shrinking of a gel,with the expulsion of water or other liquid from it.
Synthesis:
The construction of a compound by the union of elements or simple compounds.
Tincture:
A solution of a medicinal substance in alcohol.
Titration:
The process of determining the quantity of a substance in a solution by adding
a measured volume of a standard solution until the desired reaction has been
affected.
Transmutation:
The conversion of one element into another in a nuclear reaction.
Tyndall effect:
The reflection of a beam of light by the dispersed particles of a colloidal
solution,making visible the path of the light.
Unsaturated compounds:
Organic compounds containing double or triple bonds and are capable of forming
addition products.
Unsaturated solution:
A solution containing less solute than the amount needed to make a saturated
solution.
Valence:
A number that represents the combining power of an element or radical.
Valence electrons:
The electrons located in the outermost shell of an atom.
Water of crystallization:
Water present in the crystal of a hydrate.
Zwitterion:
A dipolar ion carrying both a positive and a negative charge.
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