EXAMPLES OF CHEMICALS THAT FLAVOR FOODS IUPAC name: Ethyl (2E,4Z)-2,4-decadienoate. Ethyl maltol. C 7 H 8 O 3. Caramelized sugar, cooked fruit, and cotton candy flavors; this is a synthetic chemical. IUPAC name: 2-Ethyl-3-hydroxy-4-pyranone. Ethyl propionate. C 5 H 10 O 2. Fruity flavor, pineapple odor; traces found in strawberries and kiwis. CHEMICOOL — COOLER THAN ABSOLUTE ZERO!CHEMICOOLACTINIUMALUMINUMAMERICIUMANTIMONYARGON This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. DENSITIES OF THE ELEMENTS Element Densities - Alphabetical and Periodic Table. Density data for the chemical elements measured at room-temperature / 20 °C presented in two different ways: alphabetical list and periodic table. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases. EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is

IRON NUTRITION

Best Foods: beef, liver, fortified cereals, oysters. Tolerable Upper Adult Intake Level For Iron: 45 mg. Iron Supplements available as: ferrous fumarate, ferrous sulfate, and ferrous gluconate. Beef is an excellent source of iron. Drinking fruit juices high in vitamin C, such as orange or kiwi or strawberry, with a meal helps you absorb

iron.

DEFINITION OF THE MADELUNG RULE The Madelung rule tries to establish the order in which electrons fill energy sublevels of atoms. The aufbau principle says that in the ground state of an atom, electrons always occupy the lowest available energy sublevel.. The Madelung rule, summarized in the diagram below, shows the order electrons add to sublevels.. The Madelung Rule is unreliable for elements higher than element 20, calcium.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF POTENTIOMETRY Potentiometry is one of the methods of electroanalytical chemistry. It is usually employed to find the concentration of a solute in solution. In potentiometric measurements, the potential between two electrodes is measured using a high impedance voltmeter. Use of a high impedance voltmeter in important, because it ensures that current flow is DEFINITION OF PRIMARY_STANDARDS The accuracy of an analytical measurement is how close a result comes to the true value. Determining the accuracy of a measurement usually requires calibration of the analytical method with a known standard.This is often done with standards of several concentrations to make a calibration or working curve.. Some primary standards for

titration of acids:

EXAMPLES OF CHEMICALS THAT FLAVOR FOODS IUPAC name: Ethyl (2E,4Z)-2,4-decadienoate. Ethyl maltol. C 7 H 8 O 3. Caramelized sugar, cooked fruit, and cotton candy flavors; this is a synthetic chemical. IUPAC name: 2-Ethyl-3-hydroxy-4-pyranone. Ethyl propionate. C 5 H 10 O 2. Fruity flavor, pineapple odor; traces found in strawberries and kiwis. CHEMICOOL — COOLER THAN ABSOLUTE ZERO!CHEMICOOLACTINIUMALUMINUMAMERICIUMANTIMONYARGON This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. DENSITIES OF THE ELEMENTS Element Densities - Alphabetical and Periodic Table. Density data for the chemical elements measured at room-temperature / 20 °C presented in two different ways: alphabetical list and periodic table. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases. EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is

IRON NUTRITION

Best Foods: beef, liver, fortified cereals, oysters. Tolerable Upper Adult Intake Level For Iron: 45 mg. Iron Supplements available as: ferrous fumarate, ferrous sulfate, and ferrous gluconate. Beef is an excellent source of iron. Drinking fruit juices high in vitamin C, such as orange or kiwi or strawberry, with a meal helps you absorb

iron.

DEFINITION OF THE MADELUNG RULE The Madelung rule tries to establish the order in which electrons fill energy sublevels of atoms. The aufbau principle says that in the ground state of an atom, electrons always occupy the lowest available energy sublevel.. The Madelung rule, summarized in the diagram below, shows the order electrons add to sublevels.. The Madelung Rule is unreliable for elements higher than element 20, calcium.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF POTENTIOMETRY Potentiometry is one of the methods of electroanalytical chemistry. It is usually employed to find the concentration of a solute in solution. In potentiometric measurements, the potential between two electrodes is measured using a high impedance voltmeter. Use of a high impedance voltmeter in important, because it ensures that current flow is DEFINITION OF PRIMARY_STANDARDS The accuracy of an analytical measurement is how close a result comes to the true value. Determining the accuracy of a measurement usually requires calibration of the analytical method with a known standard.This is often done with standards of several concentrations to make a calibration or working curve.. Some primary standards for

titration of acids:

PERIODIC TABLE OF ELEMENTS AND CHEMISTRY The periodic table we use today is based on the one devised and published by Dmitri Mendeleev in 1869. Mendeleev found he could arrange the 65 elements then known in a grid or table so that each element had: 1. A higher atomic weight than the one on its left. For example, magnesium (atomic weight 24.3) is placed to the right of

sodium (atomic

EXAMPLES OF HIGH POLARITY SOLVENTS Notes: Reichardt values multiplied ×10 for easier comparison with Snyder data. Snyder data sourced from Modern Methods of Pharmaceutical Analysis, Second Edition, Volume 2, Roger E. Schirmer, CRC Press, 1990.; Reichardt data sourced from Solvents and Solvent Effects in Organic Chemistry, Third Edition, Christian Reichardt, Wiley-VCH, 2003.; ε and μ data from CRC Handbook of Chemistry and

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF ISOSTERES Isosteres are atoms, molecules, or ions of similar size containing the same number of atoms and valence electrons. Example 1. Consider neon, the noble gas at the end of the second row of the periodic table. To the left of it, fluorine has one fewer electron. If fluorine ionizes, it gains an electron to become F -, which is an isostere of Ne. DEFINITION OF PRIMARY_STANDARDS The accuracy of an analytical measurement is how close a result comes to the true value. Determining the accuracy of a measurement usually requires calibration of the analytical method with a known standard.This is often done with standards of several concentrations to make a calibration or working curve.. Some primary standards for

titration of acids:

DEFINITION OF REDOX_REACTIONS_INTRODUCTION Predict what might happen when a piece of copper wire in a solution of 2% AgNO3.. If you try this experiment, you will initially see that the copper is a shiny copper color and the solution is clear. In less than one hour the solution is light blue and the wire is covered with shiny silver needles. What happened? DEFINITION OF MORSE_POTENTIAL Two atoms that can form a bond will do so to create a diatomic molecule when they approach each other closely. This situation is possible provided the potential energy of the product is lower than that of the reactants. We describe the energy minimum with a potential energy curve, called a potential well.. The potential energy, V(R), of a diatomic molecule can be described by the Morse potential:

ZINC NUTRITION

Zinc is an essential mineral for human health. The recommended dietary allowances (RDAs) fpr adults are from 8 mg to 11 mg per day. DEFINITION OF STANDARD_DEVIATION If data values are all equal to one another, then the standard deviation is zero. If a high proportion of data points lie near the mean value, then the standard deviation is small.. An experiment that yields data with a low standard deviation is said have high precision.. If a high proportion of data points lie far from the mean value, then the standard deviation is large. FACTS ABOUT CARBON DIOXIDE 12 striking facts about carbon dioxide. 1. Chilling Effects. Frozen carbon dioxide, often called dry ice, doesn’t melt. At atmospheric pressure it sublimes at −78.5 °C going straight from solid to gas. The gas is so cold that moisture in the air condenses on it, creating a dense fog used in stage and movie effects. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is DEFINITION OF THE MADELUNG RULE The Madelung rule tries to establish the order in which electrons fill energy sublevels of atoms. The aufbau principle says that in the ground state of an atom, electrons always occupy the lowest available energy sublevel.. The Madelung rule, summarized in the diagram below, shows the order electrons add to sublevels.. The Madelung Rule is unreliable for elements higher than element 20, calcium. DEFINITION OF PROJECTION_FORMULA A formal two-dimensional representation of a three-dimensional molecular structure obtained by projection of bonds (symbolised as lines) onto a plane with or without the designation of the positions of relevant atoms by their chemical symbols.. A projection formula which indicates the spatial arrangement of bonds is called a stereochemical formula or stereoformula. DEFINITION OF NUCLEARITY The nuclearity of a single coordination entity indicates the number of central atoms joined by bridging ligands or metal-metal bonds. The simplest nuclearity is mononuclear, followed by dinuclear, trinuclear, tetranuclear, pentanuclear, hexanuclear, polynuclear. DEFINITION OF AUTODOPING Search the Dictionary for More Terms. Return to top of page. Copyright � 2020 chemicool.com Chemistry Dictionary | Birth of the Elements | Tools | Periodic Table

DEFINITION OF FILM

Definition of film. A layer of contaminant on part or all of a wafer. An example is wax that has migrated onto the wafer surface.

DEFINITION OF SEED

Definition of seed. in flat panel display substrates, a gaseous inclusion less than 0.5 mm long. DEFINITION OF NATIONAL_ELECTRIC_CODE_NEC_HIGH_VOLTAGE Definition of National Electric Code (NEC) high voltage. as defined by the NEC, voltage greater than 600 V. (Article 710) Search the Dictionary for More Terms EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is DEFINITION OF THE MADELUNG RULE The Madelung rule tries to establish the order in which electrons fill energy sublevels of atoms. The aufbau principle says that in the ground state of an atom, electrons always occupy the lowest available energy sublevel.. The Madelung rule, summarized in the diagram below, shows the order electrons add to sublevels.. The Madelung Rule is unreliable for elements higher than element 20, calcium. DEFINITION OF PROJECTION_FORMULA A formal two-dimensional representation of a three-dimensional molecular structure obtained by projection of bonds (symbolised as lines) onto a plane with or without the designation of the positions of relevant atoms by their chemical symbols.. A projection formula which indicates the spatial arrangement of bonds is called a stereochemical formula or stereoformula. DEFINITION OF NUCLEARITY The nuclearity of a single coordination entity indicates the number of central atoms joined by bridging ligands or metal-metal bonds. The simplest nuclearity is mononuclear, followed by dinuclear, trinuclear, tetranuclear, pentanuclear, hexanuclear, polynuclear. DEFINITION OF AUTODOPING Search the Dictionary for More Terms. Return to top of page. Copyright � 2020 chemicool.com Chemistry Dictionary | Birth of the Elements | Tools | Periodic Table

DEFINITION OF FILM

Definition of film. A layer of contaminant on part or all of a wafer. An example is wax that has migrated onto the wafer surface.

DEFINITION OF SEED

Definition of seed. in flat panel display substrates, a gaseous inclusion less than 0.5 mm long. DEFINITION OF NATIONAL_ELECTRIC_CODE_NEC_HIGH_VOLTAGE Definition of National Electric Code (NEC) high voltage. as defined by the NEC, voltage greater than 600 V. (Article 710) Search the Dictionary for More Terms EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases. EXAMPLES OF CHEMICALS THAT FLAVOR FOODS IUPAC name: Ethyl (2E,4Z)-2,4-decadienoate. Ethyl maltol. C 7 H 8 O 3. Caramelized sugar, cooked fruit, and cotton candy flavors; this is a synthetic chemical. IUPAC name: 2-Ethyl-3-hydroxy-4-pyranone. Ethyl propionate. C 5 H 10 O 2. Fruity flavor, pineapple odor; traces found in strawberries and kiwis. DEFINITION OF ISOSTERES Isosteres are atoms, molecules, or ions of similar size containing the same number of atoms and valence electrons. Example 1. Consider neon, the noble gas at the end of the second row of the periodic table. To the left of it, fluorine has one fewer electron. If fluorine ionizes, it gains an electron to become F -, which is an isostere of Ne. DEFINITION OF MIGRATION It can be: (1) The (usually intramolecular) transfer of an atom or group during the course of a molecular rearrangement. (2) The movement of a bond to a new position, within the same molecular entity, is known as "bond migration". Allylic rearrangements exemplify both of the above types of migration. For example: (3) Movement of a

substance's

DEFINITION OF MINERAL OILS Properties and Uses. Inexpensive Hydrocarbons: Mineral oils are not expensive to produce and are widely used in applications appropriate to their properties.. Grades: Different grades of mineral oil are available - these differ in their viscosity (runniness).Increasing the average chain length of the alkanes in mineral oil makes it more viscous (less runny). DEFINITION OF HARD ACID Hard acids are Lewis acids that are only weakly polarizable.. Other things being approximately equal: hard acids react faster with hard bases and form stronger bonds with them; soft acids react faster with soft bases and form stronger bonds with them

DEFINITION OF ANTI

In the representation of stereochemical relationships "anti" means "on opposite sides" of a reference plane, in contrast to "syn" which means "on the same side", as in the following examples. (A) Two substituents attached to atoms joined by a single bond are anti if the torsion angle (dihedral angle) between the bonds to the substituents is greater than 90o, or syn if it is less than 90o. DEFINITION OF POTENTIOMETRY Potentiometry is one of the methods of electroanalytical chemistry. It is usually employed to find the concentration of a solute in solution. In potentiometric measurements, the potential between two electrodes is measured using a high impedance voltmeter. Use of a high impedance voltmeter in important, because it ensures that current flow is FACTS ABOUT CARBON DIOXIDE 12 striking facts about carbon dioxide. 1. Chilling Effects. Frozen carbon dioxide, often called dry ice, doesn’t melt. At atmospheric pressure it sublimes at −78.5 °C going straight from solid to gas. The gas is so cold that moisture in the air condenses on it, creating a dense fog used in stage and movie effects. PERIODIC TABLE OF ELEMENTS AND CHEMISTRY1 H2 HE3 LI4 BE5 B6 C The periodic table we use today is based on the one devised and published by Dmitri Mendeleev in 1869. Mendeleev found he could arrange the 65 elements then known in a grid or table so that each element had: 1. A higher atomic weight than the one on its left. For example, magnesium (atomic weight 24.3) is placed to the right of

sodium (atomic

CHEMICOOL — COOLER THAN ABSOLUTE ZERO!CHEMICOOLACTINIUMALUMINUMAMERICIUMANTIMONYARGON This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is DENSITIES OF THE ELEMENTS Element Densities - Alphabetical and Periodic Table. Density data for the chemical elements measured at room-temperature / 20 °C presented in two different ways: alphabetical list and periodic table. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases.

IRON NUTRITION

Best Foods: beef, liver, fortified cereals, oysters. Tolerable Upper Adult Intake Level For Iron: 45 mg. Iron Supplements available as: ferrous fumarate, ferrous sulfate, and ferrous gluconate. Beef is an excellent source of iron. Drinking fruit juices high in vitamin C, such as orange or kiwi or strawberry, with a meal helps you absorb

iron.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF MORSE_POTENTIAL Two atoms that can form a bond will do so to create a diatomic molecule when they approach each other closely. This situation is possible provided the potential energy of the product is lower than that of the reactants. We describe the energy minimum with a potential energy curve, called a potential well.. The potential energy, V(R), of a diatomic molecule can be described by the Morse potential: DEFINITION OF STANDARD_DEVIATION If data values are all equal to one another, then the standard deviation is zero. If a high proportion of data points lie near the mean value, then the standard deviation is small.. An experiment that yields data with a low standard deviation is said have high precision.. If a high proportion of data points lie far from the mean value, then the standard deviation is large. DEFINITION OF POTENTIOMETRY Potentiometry is one of the methods of electroanalytical chemistry. It is usually employed to find the concentration of a solute in solution. In potentiometric measurements, the potential between two electrodes is measured using a high impedance voltmeter. Use of a high impedance voltmeter in important, because it ensures that current flow is PERIODIC TABLE OF ELEMENTS AND CHEMISTRY1 H2 HE3 LI4 BE5 B6 C The periodic table we use today is based on the one devised and published by Dmitri Mendeleev in 1869. Mendeleev found he could arrange the 65 elements then known in a grid or table so that each element had: 1. A higher atomic weight than the one on its left. For example, magnesium (atomic weight 24.3) is placed to the right of

sodium (atomic

CHEMICOOL — COOLER THAN ABSOLUTE ZERO!CHEMICOOLACTINIUMALUMINUMAMERICIUMANTIMONYARGON This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is DENSITIES OF THE ELEMENTS Element Densities - Alphabetical and Periodic Table. Density data for the chemical elements measured at room-temperature / 20 °C presented in two different ways: alphabetical list and periodic table. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases.

IRON NUTRITION

Best Foods: beef, liver, fortified cereals, oysters. Tolerable Upper Adult Intake Level For Iron: 45 mg. Iron Supplements available as: ferrous fumarate, ferrous sulfate, and ferrous gluconate. Beef is an excellent source of iron. Drinking fruit juices high in vitamin C, such as orange or kiwi or strawberry, with a meal helps you absorb

iron.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF MORSE_POTENTIAL Two atoms that can form a bond will do so to create a diatomic molecule when they approach each other closely. This situation is possible provided the potential energy of the product is lower than that of the reactants. We describe the energy minimum with a potential energy curve, called a potential well.. The potential energy, V(R), of a diatomic molecule can be described by the Morse potential: DEFINITION OF STANDARD_DEVIATION If data values are all equal to one another, then the standard deviation is zero. If a high proportion of data points lie near the mean value, then the standard deviation is small.. An experiment that yields data with a low standard deviation is said have high precision.. If a high proportion of data points lie far from the mean value, then the standard deviation is large. DEFINITION OF POTENTIOMETRY Potentiometry is one of the methods of electroanalytical chemistry. It is usually employed to find the concentration of a solute in solution. In potentiometric measurements, the potential between two electrodes is measured using a high impedance voltmeter. Use of a high impedance voltmeter in important, because it ensures that current flow is EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases. DENSITIES OF THE ELEMENTS Element Densities - Alphabetical and Periodic Table. Density data for the chemical elements measured at room-temperature / 20 °C presented in two different ways: alphabetical list and periodic table.

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this MELTING POINTS OF THE ELEMENTS Melting point data for the elements presented in two ways: periodic table and alphabetical list. DEFINITION OF REDOX_REACTIONS_INTRODUCTION Predict what might happen when a piece of copper wire in a solution of 2% AgNO3.. If you try this experiment, you will initially see that the copper is a shiny copper color and the solution is clear. In less than one hour the solution is light blue and the wire is covered with shiny silver needles. What happened? DEFINITION OF PRIMARY_STANDARDS The accuracy of an analytical measurement is how close a result comes to the true value. Determining the accuracy of a measurement usually requires calibration of the analytical method with a known standard.This is often done with standards of several concentrations to make a calibration or working curve.. Some primary standards for

titration of acids:

FACTS ABOUT HELIUM

10 Interesting Facts about Element 2. By Dr. Doug Stewart. 1. Helium is the second most abundant element in the universe. 2. In 1928 helium became available on the open market for the first time. 3. Helium is so light that Earth’s gravity is not strong enough to hold on to it. MERCURY ELEMENT FACTS Mercury is a dense, silvery-white, poisonous metal with a mirror-like appearance. It is the only common metal that is liquid at room temperature. Mercury evaporates slowly at room temperature. Others metals that are liquid near room temperature are gallium, francium and

cesium.

TITANIUM ELEMENT FACTS Pure titanium is a light, silvery-white, hard, lustrous metal. It has excellent strength and corrosion resistance and also has a high strength to weight ratio. Titanium’s corrosion rate is so low that after 4000 years in seawater, corrosion would only have penetrated the metal to the thickness of IRIDIUM ELEMENT FACTS Iridium is a rare, hard, lustrous, brittle, very dense platinum-like metal. Chemically it is very unreactive. It is the most corrosion-resistant metal known and it resists attack by any acid. Iridium is attacked by molten salts such as sodium chloride (NaCl) and sodium cyanide (NaCN). EXAMPLES OF CHEMICALS THAT FLAVOR FOODS IUPAC name: Ethyl (2E,4Z)-2,4-decadienoate. Ethyl maltol. C 7 H 8 O 3. Caramelized sugar, cooked fruit, and cotton candy flavors; this is a synthetic chemical. IUPAC name: 2-Ethyl-3-hydroxy-4-pyranone. Ethyl propionate. C 5 H 10 O 2. Fruity flavor, pineapple odor; traces found in strawberries and kiwis. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases. EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF NUCLEARITY The nuclearity of a single coordination entity indicates the number of central atoms joined by bridging ligands or metal-metal bonds. The simplest nuclearity is mononuclear, followed by dinuclear, trinuclear, tetranuclear, pentanuclear, hexanuclear, polynuclear. DEFINITION OF AUTODOPING Search the Dictionary for More Terms. Return to top of page. Copyright � 2020 chemicool.com Chemistry Dictionary | Birth of the Elements | Tools | Periodic Table DEFINITION OF HARD ACID Hard acids are Lewis acids that are only weakly polarizable.. Other things being approximately equal: hard acids react faster with hard bases and form stronger bonds with them; soft acids react faster with soft bases and form stronger bonds with them

DEFINITION OF ANTI

In the representation of stereochemical relationships "anti" means "on opposite sides" of a reference plane, in contrast to "syn" which means "on the same side", as in the following examples. (A) Two substituents attached to atoms joined by a single bond are anti if the torsion angle (dihedral angle) between the bonds to the substituents is greater than 90o, or syn if it is less than 90o.

DEFINITION OF SEED

Definition of seed. in flat panel display substrates, a gaseous inclusion less than 0.5 mm long. DEFINITION OF NATIONAL_ELECTRIC_CODE_NEC_HIGH_VOLTAGE Definition of National Electric Code (NEC) high voltage. as defined by the NEC, voltage greater than 600 V. (Article 710) Search the Dictionary for More Terms EXAMPLES OF CHEMICALS THAT FLAVOR FOODS IUPAC name: Ethyl (2E,4Z)-2,4-decadienoate. Ethyl maltol. C 7 H 8 O 3. Caramelized sugar, cooked fruit, and cotton candy flavors; this is a synthetic chemical. IUPAC name: 2-Ethyl-3-hydroxy-4-pyranone. Ethyl propionate. C 5 H 10 O 2. Fruity flavor, pineapple odor; traces found in strawberries and kiwis. EXAMPLES OF HARD AND SOFT ACIDS AND BASES Soft Lewis acids and bases are relatively large, polarizable atoms, ions, and molecules.. Hard Lewis acids and bases are relatively small and less polarizable.. In practice, soft acids prefer to associate with soft bases, and hard acids prefer to associate with hard bases. EXAMPLES OF SUPERACIDS Acidity is indicated by the Hammett acidity function, H 0.. Like pH, H 0 is a measure of acidity; lower values of H 0 mean higher protonating power. Like pH, H 0 is a logarithmic scale.. 100% sulfuric acid has an H 0 of -12. Compare this with fluoroantimonic acid's H 0 of -31. This means fluoroantimonic acid is 10 19 more acidic than pure sulfuric acid. That's a bigger difference than there is

DEFINITION OF QSAR

Receptor. A receptor is a molecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (neurotransmitter, hormone, lymphokine, lectin, drug, etc.).. Receptor mapping. Receptor mapping is the technique used to describe the geometric and/or electronic features of a binding site when insufficient structural data for this DEFINITION OF NUCLEARITY The nuclearity of a single coordination entity indicates the number of central atoms joined by bridging ligands or metal-metal bonds. The simplest nuclearity is mononuclear, followed by dinuclear, trinuclear, tetranuclear, pentanuclear, hexanuclear, polynuclear. DEFINITION OF AUTODOPING Search the Dictionary for More Terms. Return to top of page. Copyright � 2020 chemicool.com Chemistry Dictionary | Birth of the Elements | Tools | Periodic Table DEFINITION OF HARD ACID Hard acids are Lewis acids that are only weakly polarizable.. Other things being approximately equal: hard acids react faster with hard bases and form stronger bonds with them; soft acids react faster with soft bases and form stronger bonds with them

DEFINITION OF ANTI

In the representation of stereochemical relationships "anti" means "on opposite sides" of a reference plane, in contrast to "syn" which means "on the same side", as in the following examples. (A) Two substituents attached to atoms joined by a single bond are anti if the torsion angle (dihedral angle) between the bonds to the substituents is greater than 90o, or syn if it is less than 90o.

DEFINITION OF SEED

Definition of seed. in flat panel display substrates, a gaseous inclusion less than 0.5 mm long. DEFINITION OF NATIONAL_ELECTRIC_CODE_NEC_HIGH_VOLTAGE Definition of National Electric Code (NEC) high voltage. as defined by the NEC, voltage greater than 600 V. (Article 710) Search the Dictionary for More Terms EXAMPLES OF CHEMICALS THAT FLAVOR FOODS IUPAC name: Ethyl (2E,4Z)-2,4-decadienoate. Ethyl maltol. C 7 H 8 O 3. Caramelized sugar, cooked fruit, and cotton candy flavors; this is a synthetic chemical. IUPAC name: 2-Ethyl-3-hydroxy-4-pyranone. Ethyl propionate. C 5 H 10 O 2. Fruity flavor, pineapple odor; traces found in strawberries and kiwis. DEFINITION OF THE MADELUNG RULE The Madelung rule tries to establish the order in which electrons fill energy sublevels of atoms. The aufbau principle says that in the ground state of an atom, electrons always occupy the lowest available energy sublevel.. The Madelung rule, summarized in the diagram below, shows the order electrons add to sublevels.. The Madelung Rule is unreliable for elements higher than element 20, calcium.

DEFINITION OF ANTI

In the representation of stereochemical relationships "anti" means "on opposite sides" of a reference plane, in contrast to "syn" which means "on the same side", as in the following examples. (A) Two substituents attached to atoms joined by a single bond are anti if the torsion angle (dihedral angle) between the bonds to the substituents is greater than 90o, or syn if it is less than 90o. DEFINITION OF MINERAL OILS Properties and Uses. Inexpensive Hydrocarbons: Mineral oils are not expensive to produce and are widely used in applications appropriate to their properties.. Grades: Different grades of mineral oil are available - these differ in their viscosity (runniness).Increasing the average chain length of the alkanes in mineral oil makes it more viscous (less runny). DEFINITION OF ISOSTERES Isosteres are atoms, molecules, or ions of similar size containing the same number of atoms and valence electrons. Example 1. Consider neon, the noble gas at the end of the second row of the periodic table. To the left of it, fluorine has one fewer electron. If fluorine ionizes, it gains an electron to become F -, which is an isostere of Ne.

IRON NUTRITION

Best Foods: beef, liver, fortified cereals, oysters. Tolerable Upper Adult Intake Level For Iron: 45 mg. Iron Supplements available as: ferrous fumarate, ferrous sulfate, and ferrous gluconate. Beef is an excellent source of iron. Drinking fruit juices high in vitamin C, such as orange or kiwi or strawberry, with a meal helps you absorb

iron.

DEFINITION OF CATHODE & ANODE IN GALVANIC AND ELECTROLYTIC The processes here are the galvanic cell's in reverse. The current from the power source pushes electrons on to the electrode on the right of the diagram, where they cause reduction of species - hence this electrode is the cathode. In electrolytic cells, the cathode is negatively charged. Electrons are pushed on to the cathode by the

external

DEFINITION OF POTENTIOMETRY Potentiometry is one of the methods of electroanalytical chemistry. It is usually employed to find the concentration of a solute in solution. In potentiometric measurements, the potential between two electrodes is measured using a high impedance voltmeter. Use of a high impedance voltmeter in important, because it ensures that current flow is DEFINITION OF AQUATION The incorporation of one or more integral molecules of water into another species with or without displacement of one or more other atoms or groups. For example the incorporation of water into the inner ligand sphere of an inorganic complex is an aquation reaction . See

also hydration.

DEFINITION OF BAND

Search the Dictionary for More Terms. Return to top of page. Copyright � 2020 chemicool.com Chemistry Dictionary | Birth of the Elements | Tools | Periodic Table

Chemicool

Group

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

Period

1

1

H

2

He

2

3

Li

4

Be

5

B

6

C

7

N

8

O

9

F

10

Ne

3

11

Na

12

Mg

13

Al

14

Si

15

P

16

S

17

Cl

18

Ar

4

19

K

20

Ca

21

Sc

22

Ti

23

V

24

Cr

25

Mn

26

Fe

27

Co

28

Ni

29

Cu

30

Zn

31

Ga

32

Ge

33

As

34

Se

35

Br

36

Kr

5

37

Rb

38

Sr

39

Y

40

Zr

41

Nb

42

Mo

43

Tc

44

Ru

45

Rh

46

Pd

47

Ag

48

Cd

49

In

50

Sn

51

Sb

52

Te

53

I

54

Xe

6

55

Cs

56

Ba

57-71

72

Hf

73

Ta

74

W

75

Re

76

Os

77

Ir

78

Pt

79

Au

80

Hg

81

Tl

82

Pb

83

Bi

84

Po

85

At

86

Rn

7

87

Fr

88

Ra

89-103

104

Rf

105

Db

106

Sg

107

Bh

108

Hs

109

Mt

110

Ds

111

Rg

112

Cn

113

Nh

114

Fl

115

Mc

116

Lv

117

Ts

118

Og

57

La

58

Ce

59

Pr

60

Nd

61

Pm

62

Sm

63

Eu

64

Gd

65

Tb

66

Dy

67

Ho

68

Er

69

Tm

70

Yb

71

Lu

89

Ac

90

Th

91

Pa

92

U

93

Np

94

Pu

95

Am

96

Cm

97

Bk

98

Cf

99

Es

100

Fm

101

Md

102

No

103

Lr

PERIODIC TABLE KEY

X

Synthetic Elements

X

Liquids or melt at close to room temp.

X

Solids

X

Gases

Alkali Metals

Alkali Earth Metals

Transition Metals

Other Metals

Metalloids

Other Non Metals

Halogens

Noble Gases

Lanthanides

& Actinides

The Periodic Table

"If all the elements are arranged in the order of their atomic weights, a periodic repetition of properties is obtained. This is expressed by the law of periodicity." _Dmitri Mendeleev, Principles of Chemistry, Vol. 2, 1902, P. F.

Collier, p17._

"We have here a proof that there is in the atom a fundamental quantity, which increases by regular steps as one passes from one element to the next. This quantity can only be the charge on the central positive nucleus, of the existence of which we already have

definite proof."

_Henry Moseley, Philosophical Magazine, Vol. 26, 1913, p1030._ "The chemistry of an atom depends only on the number of electrons, which equals the number of protons and is called the atomic number. Chemistry is simply numbers, an idea Pythagoras would have liked. If you are an atom with one proton, you are hydrogen; two, helium;....." _Carl Sagan, Cosmos, 1980, Random House, p223. Photo: NASA. _

THE PERIODIC TABLE

Author: Dr. Doug Stewart The periodic table we use today is based on the one devised and published by Dmitri Mendeleev in 1869. Mendeleev found he could arrange the 65 elements then known in a grid or table so that each element had: 1. A higher atomic weight than the one on its left. For example, magnesium (atomic weight 24.3) is placed to the right of sodium (atomic weight 23.0): 2. Similar chemical properties to other elements in the same column - in other words similar chemical reactions. Magnesium, for example, is placed in the alkali earths' column, with other elements whose reactions are similar: Mendeleev realized that the table in front of him lay at the very heart of chemistry. And more than that, Mendeleev saw that his table was incomplete - there were spaces where elements should be, but no-one had discovered them. Just as Adams and Le Verrier could be said to have discovered the planet Neptune on paper, Mendeleev could be said to have discovered germanium on paper. He called this new element _eka-silicon_, after observing a gap in the periodic table between silicon and tin: Similarly, Mendeleev discovered gallium (_eka_-aluminum) and scandium (_eka_-boron) on paper, because he predicted their existence and their properties before their actual discoveries. Periodic Table Image Click image to enlarge Although Mendeleev had made a crucial breakthrough, he made little further progress. With the benefit of hindsight, we know that Mendeleev's periodic table was underpinned by false reasoning. Mendeleev believed, incorrectly, that chemical properties were determined by atomic weight. Of course, this was perfectly reasonable when we consider scientific knowledge in 1869. In 1869 the electron itself had not been discovered - that didn't happen for another 27 years. In fact, it took all of 44 years for the correct explanation of the regular patterns in Mendeleev's periodic table to be found... READ MORE... The Periodic Table continued Copyright © 2018 chemicool.com Chemistry Dictionary

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