| A | B |
|---|
| Atom | basic unit of matter |
| nucleus | Center of the atom |
| electron | negatively charged particle |
| element | a pure substance that consists entirely of one type of atom |
| isotope | atoms of the same element that differ in the number of neutrons they contain |
| compound | a substance formed by the chemical combination of two or more elements in definte proportions |
| ionic bond | formed when one or more electrons are transferred from one atom to another |
| ion | A positively or negatively charged atom |
| covalent bond | electrons are shared by atoms; |
| molecule | when atoms are joined together by covalent bonds |
| van der Waals forces | slight attraction that develops between oppositely charged regions of nearby molecules |
| hydrogen bond | attraction between a hyrogen atom with a partial positive charge and another atom with a partial negative charge |
| cohesion | attraction between molecules of the same substance |
| adhesion | attraction between molecules of different substances |
| mixture | a material composed of two or more elements or compounds that are physically mixed together, but not chemically combined |
| solution | when ions become dispersed evenly in water |
| solute | substance dissolved |
| solvent | substance in which solute is dissolved |
| suspension | mixtures of water and nondissolved material |
| pH scale | measurement system that indicates the concentration of H+ ions in a solution; acid 1-6, base 8-14, neutral = 7 |
| Base | any compound that produces hydroxide (OH-) ions in a solution |
| Buffer | weak acids or bases that can react with strong acids or bases to prevent sharp changes in pH |
| Monomer | small units that join together to form polymers |
| Polymer | large molecules built by monomers |
| Carbohydrate | compounds made up of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio; source of energy |
| monosaccharide | single sugar molecules |
| complex carbohydrate | large macromolecule formed from monosaccharides |
| lipid | not soluble in water, made of carbon and hydrogen; fats, oils, and waxes |
| nucleic acid | macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus; transmit hereditary information |
| nucleotide | made of 5 carbon sugar, phosphate group, and nitrogen base; make up nucleic acids |
| protein | made of nitrogen, carbon, hydrogen, and oxygen; make up structures and regulate processes |
| amino acids | make up proteins; made of amino groups and carboxyl groups |
| chemical reaction | a process that changes one set of chemicals into another |
| reactants | elements or compounds that enter into a chemical reaction |
| products | elements or compounds produced by a chemical reaction |
| activation energy | energy needed to get a reaction started |
| catalyst | a substance that speeds up the rate of a chemical reaction |
| enzyme | proteins that act as biological catalysts |
| substrate | pure water and have a value below 7 |
| acid | any compound that forms H+ ions than pure water and have a value below 7 |
