Applied Chemistry Glossary absorption The incorporation of one substance into another substance by chemical or physical means. acetic anhydride Organic compounds derived of methyl acetate and carbon monoxide. acid A compound that releases hydrogen ions (H+) in water. An acid has a pH of less than 7. acid, strong An acid that completely dissociates into hydrogen ions in solution. acid, weak An acid that partially dissociates into hydrogen ions in solution. acidity The measure of the strength of an acid. adsorption The adhesion of molecules to the surface of another phase. alcohol An organic compound with a carbon bound to a hydroxyl group. aldehyde An organic compound with a carbon bound to a -(C=O)-H group. alkalinity The measure of strength of a base. alkane A hydrocarbon in which the carbon atoms share a single bond. alkene A hydrocarbon in which at least 1 carbon pair share a double bond. alkyne A hydrocarbon in which at least 1 carbon pair share a triple bond. amine An organic compound that contains a nitrogen atom bound only to carbon and possibly hydrogen atoms. aromatic hydrocarbon A hydrocarbon that contains a benzene ring in its structure. Aromatic hydrocarbons are also known as arenes. atomic number The number of protons in the nucleus of an atom. atomic weight The average mass of an atom of an element, usually expressed in atomic mass units (amu). The weight of one mole of an element is equal to the elementís atomic weight. base A compound that yields hydroxide (OH-) ions in water. A base has a pH greater than 7. base, strong A base that completely dissociates in solution. base, weak A base that has a low degree of dissociation in solution. benzene ring A hexagonal ring arrangement found in benzene and other aromatic compounds, consisting of six carbon atoms with alternating single and double bonds between them. carbonyl An organic molecule that contains a carbon atom with a double bond to oxygen (C=O). carboxylic acid A carboxylic acid is an organic molecule with a (C=O)-OH group. catalyst A substance that increases the rate of a chemical reaction, without being consumed or produced by the reaction. caustic A base compound. chemical equation Uses symbols to represent a chemical reaction. Reactants are on the left of the equation and products are on the right. A single arrow indicates an irreversible reaction and a double arrow indicates a reversible reaction. Also called a reaction equation. chemical reaction Occurs when a substance (or substances) is changed into one or more new substances by forming or breaking chemical bonds. chemistry The study of matter and how it changes in chemical reactions. collision effectiveness How often reactants in a chemical reaction bond when they collide. Collision effectiveness affects reaction rate. collision frequency How often reactant in a chemical reaction collide. Collision frequency affects reaction rate. combustion reaction A reaction in which a compound reacts with oxygen to produce heat. compound A pure substance made up of two or more elements bonded together in defined proportion. Compounds cannot be separated by physical means. compound mixture A substance consisting of two or more compounds in any proportion. concentration The comparison of how much solute in is the solution. Concentration is measured in different ways including percent by weight, parts per million (ppm), parts per billion (ppb), molarity, normality condensation A phase change in which a substance changes from a gas to a liquid. covalent bond A chemical bond in which 2 or more atoms share electrons. Covalent bonds can be single (two shared electrons), double (four shared electrons), or triple (six shared electrons). decomposition A reaction in which a compound is broken down into simpler compounds or elements. deposition A phase change in which a substance changes from a gas to a solid. dilute, dilution A solution that contains a relatively small quantity of solute as compared to solvent. double replacement A chemical reaction between two compounds, in which positive ions are exchanged to form two new compounds with the same ions. electron A negatively charged (-) particle that orbits the nucleus of an atom. electron shell Made up of negatively charged electrons orbiting the nucleus of an atom. The electrons in the outermost shell, called the valence shell, are most often involved directly in chemical reactions. element A pure substance that contains only one type of atom. The atoms of an element have the same number of protons so therefore have the same atomic number but can have different number of neutrons so therefore can have different mass number. The known elements as listed in the Periodic Table of Elements endothermic reaction A chemical process that consumes heat. equilibrium, reaction In a solution, an equal number of solute molecules dissolve as redeposit. In a reaction, a state in which the reactant reactions occur at the same rate as the product reactions so that the concentrations of the reacting substances do not change. equilibrium, solution In a solution, an equal number of solute molecules dissolve as redeposit. See also: saturation equivalent The number of hydronium ions released by an acid or hydroxide ions released by a base. Equivalents are used to calculate the normality of a solution. ester An organic compound derived of the carboxylic acids in which the -OH from the carboxyl group is replaced by an -OR from an alcohol. evaporation A phase change in which a substance changes from a liquid to a gas. exothermic reaction A chemical reaction that produces heat as a product. freezing A phase change in which a substance changes from a liquid to a solid state. functional group Organic compounds formed by replacing a hydrogen link with other ions. gas A state of matter in which a substance has no definite shape or volume and is often colorless. Molecules in a gas move freely and are relatively far apart. glycol Organic compounds that contain two hydroxyl (OH) groups. heterogeneous mixture A mixture in which substances do not mix evenly. homogeneous mixture A mixture in which substances are mixed evenly and the properties of the mixture do not vary within samples. hydrocarbon Organic compounds consisting only of carbon and hydrogen atoms. hydronium An ion with 1 oxygen and 3 hydrogen atoms. hydroxyl An (OH)- ion or the OH group in a molecule. intermolecular forces Electrical attractions (or repulsions) between molecules that are weaker than bonds. ion An element that has lost or gained one or more electrons. Ions with extra electrons will have a negative charge; ions that have more protons than electrons (loss of electrons) will have a positive charge. ionic bond A chemical bond which occurs between ions of opposite charge. Ionic bond formation involves the transfer of electrons rather than sharing electrons (see covalent bond). ionization Occurs when ionic substances dissolve and their ions are separated from each other. isomer Organic compounds that have the same number and types of atoms but different structures. ketone An organic compound that contains a carbonyl group. Law of Conservation of Matter States that matter can neither be created nor destroyed. limiting reactant A reactant which is completely consumed during a reaction so that it limits the amount of product produced. liquid A state of matter in which a substance has a fixed volume but can take the shape of its container. Molecules in a liquid are weakly attracted, allowing them to move more freely than in a solid. litmus paper A pH indicator absorbed onto filter paper. Blue litmus paper turns red if a sample is acidic and red litmus paper turns if a sample is alkaline. mass The amount of substance that an object contains. Mass is measured in kilograms. mass number The total number of protons and neutrons in an atom or ion. matter Anything that has mass and takes up space. melting A phase change in which a substance changes from a solid to a liquid. mixture Two or more substances combined with each substance retaining its own chemical identity. Mixtures may be homogeneous or heterogeneous. Substances in a mixture may be solid, liquid or gas. molarity The concentration of a solution measured as the number of moles of solute per liter of solution. mole A unit measuring the amount of a substance equal to the number of atoms in exactly 12 g of carbon-12. 1 mole of molecules has a mass equal to the molecular weight in grams. molecular weight The sum of the atomic weights of all the atoms in the molecular formula. molecule A group of 2 or more atoms bonded chemically. neutralization reaction A reaction in which an acid and a base react to form water and a salt. neutron A subatomic particle in the nucleus of an atom which has no electric charge. non-polar compound A compound in which there an equal sharing of electrons between two different atoms. normality The concentration of a solution measured as the number of equivalents of solute per liter of solution. nucleus The positively charged mass at the center of the atom. The nucleus is made up of protons and neutrons. organic chemistry The study of carbon containing compounds. parts per billion (ppb) denotes one part per 1,000,000,000 parts. parts per million (ppm) denotes one part per 1,000,000 parts. pH Measures the acidity or alkalinity of a solution. pH indicator A liquid that changes color with an acid or base. pH meter An electronic instrument used to measure the pH of a substance. phase change Occurs when matter changes from one state to another; for example, solid to liquid or liquid to gas. A phase change is physical rather than a chemical change. polar compound A compound in which electrons are unequally shared so that the ends of the molecule temporarily have opposite charges. Electrons in a polar compound will spend more time around the atom that has the stronger pull on the shared electrons. polymer Made by bonding (reacting) repeating organic chains (monomers) into very large molecules. The process of making polymers is called polymerization. polymerization The process of making polymers. proton Positively charged particle in the nucleus of an atom. reactant The material in a chemical reaction that changes chemically to a new material (product). In a chemical equation, the reactants are on the left side of the equation. reversible reaction A chemical reaction in which the product or products can react to form the reactants. salt An ionic compound formed from a neutralization reaction of an acid and a base. saturation The point at which a solution can dissolve no more of the solute and additional amounts of solute will appear as a precipitate. single replacement A chemical reaction in which one component from a reactant decomposes and bonds with the other reactant. slurry Mixture of a liquid (usually water) and solid particles. solid State of matter with a definite volume and shape. Molecules in solids are packed close have limited movement. solubility The maximum quantity of solute that can dissolve in a certain quantity of solvent. solute In a solution, the substance that dissolves the solvent. See also: solution, solvent solution A homogeneous mixture of one or more substances (solutes) dissolved in another substance (solvent). Related: homogeneous, solute, solvent sublimation A phase change in which a substance changes from a solid to a gas. synthesis A reaction in which a complex product forms from simpler reactants. valence shell The outer most electron shell. Electrons in this shell are often involved directly in chemical reactions. vapor A gas made of a substance that is usually encountered as a liquid or solid. For example, ìwater vaporî is the gaseous form of water (H2O). vaporization A phase change in which a substance ch