| A | B |
|---|
| chemical bond | a force of attraction that holds two atoms together |
| chemical bonding | the joining of atoms to form new substances |
| theory | a unifying explanation for a broad range of hypotheses and observations that have been supported by testing |
| valence electrons | the electrons in the outermost energy level of an atom; these electrons are involved in forming chemical bonds |
| ionic bond | the force of attraction between oppositely charged ions |
| ions | charged particles that form during chemical changes when one or more valence electrons transfer from one atom to another |
| crystal lattice | a repeating three-dimensional pattern of ions |
| covalent bond | the force of attraction between the nuclei of atoms and the electrons shared by the atoms |
| molecule | a neutral group of atoms held together by covalent bonds |
| metallic bond | the force of attraction between a positively charged metal ion and the electrons in a metal |
| ductility | the ability of a substance to be drawn or pulled in a wire |
| malleability | the ability of a substance to be pounded into thin sheets |
| ionic compounds | compounds that contain ionic bonds; composed of ions arranged in a crystal lattice, they tend to have high melting and boiling points, are solid at room temperature, and dissolve in water to form solutions that conduct an electric current |
| chemical reaction | the process by which one or more substances undergo change to produce one or more different substances |
| chemical formula | a shorthand notation for a compound or a diatomic element using chemical symbols and numbers |
| subscript | a number written below and to the right of a chemical symbol in a chemical formula |
| chemical equation | a shorthand description of a chemical reaction using chemical formulas and symbols |
| products | the substances formed from a chemical reaction |
| reactants | the starting materials in a chemical reaction |
| coefficient | a number placed in front of a chemical symbol or formula; used to balance a chemical equation |
| law of conservation of mass | the law that states that mass is neither created nor destroyed in ordinary chemical and physical changes |
| synthesis reaction | a reaction in which two or more substances combine to form a single compound |
| decomposition reaction | a reaction in which a single compound breaks down to form two or more simpler substances |
| single-replacement reaction | a reaction in which an element takes the place of another element in a compound; this can occur only when a more-reactive element takes the place of a less-reactive one |
| double-replacement reaction | a reaction in which ions in two compounds switch places |
| exothermic | the term used to describe a physical or a chemical change in which energy is released or removed |
| activation energy | the minimum amount of energy needed for substances to react |
| endothermic | the term used to describe a physical or a chemical change in which energy is absorbed |
| law of conservation of energy | the law that states that energy is neither created nor destroyed |
| concentration | a measure of the amount of solute dissolved in a solvent |
| catalyst | a substance that speeds up a reaction without being permanently changed |
| inhibitor | a substance that slows down or stops a chemical reaction |
| covalent compounds | compounds that are composed of elements that are covalently bonded; these compounds are composed of independent molecules, tend to have low melting and boiling points, do not usually dissolve in water, and form solutions that do not conduct an electric current when they do dissolve |
| acid | any compound that increases the number of hydrogen ions when dissolved in water and whose solution tastes sour and can change the color of certain compounds; acids turn blue litmus red, reacts with metals to produce hydrogen gas, and reacts with limestone or baking soda to produce carbon dioxide gas |
| base | any compound that increases the number of hydroxide ions when dissolved in water and whose solutions taste bitter, feels slippery, and can change the color of certain compounds; bases turn red litmus blue |
| pH | a measure of hydronuim ion concentration in a solution; a pH of 7 is neutral; a pH less than 7 is acidic, a pH greater than 7 is basic |
| salt | an ionic compound formed from the positive ion of a base and the negative ion of an acid |
| organic compounds | covalent compounds composed of carbon-based molecules |
| biochemicals | organic compounds made by living things |
| carbohydrates | biochemicals composed of one or more simple sugars bonded together that are used as a source of energy and for energy storage |
| lipids | biochemicals that do not dissolve in water; their functions include storing energy and making up cell membranes; waxes, fats, and oils |
| proteins | biochemicals that are composed of amino acids; their functions include regulating chemical activities, transporting and storing materials, and providing structural support |
| nucleic acids | biochemicals that store information and help to build proteins and other nucleic acids; made up of subunits called nucleotides |
| hydrocarbons | organic compounds that are composed of only carbon and hydrogen |
| saturated hydrocarbon | a hydrocarbon in which each carbon atom in the molecule shares a single bond with each of four other atoms; an alkane |
| unsaturated hydrocarbon | a hydrocarbon in which at least two carbon atoms share a double bond (an alkene) or a triple bond (an alkyne) |
