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Biology Ch. 2
Chemistry of Life
| Term | Definition |
|---|---|
| acid | any compound that increases the number of hydronium ions when dissolved in water |
| activation energy | the minimum amount of energy required to start a chemical reaction |
| adhesion | the attractive force between two bodies of different substances that are in contact with each other |
| aqueous solution | a solution in which water is the solvent |
| atom | the smallest unit of an element that maintains the chemical properties of that element |
| atomic number | the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element |
| base | any compound that increases the number of hydroxide ions when dissolved in water |
| buffer | a solution made from a weak acid and its conjugate base that neutralized small amounts of acids or bases added to it |
| capillarity | the attraction between molecules that results in the rise of a liquid in small tubes |
| catalysis | the acceleration of a chemical reaction by a catalyst |
| chemical bond | the attractive force that holds atoms or ions together |
| chemical reaction | the process by which one or more substances change to produce one or more different substances |
| cohesion | the force that holds molecules of a single material together |
| compound | a substance made up of atoms of two or more different elements joined by chemical bonds |
| concentration | the amount of a particular substance in a given quantity of a mixture, solution, or ore |
| covalent bond | a bond formed when atoms share one or more pairs of electrons |
| electron | a subatomic particle that has a negative charge |
| element | a substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number |
| energy | the capacity to do work |
| enzyme | a molecule, either protein or RNA, that acts as a catalyst in biochemical reactions |
| hydrogen bond | the intermolecular force occurring when a hydrogen atom that is bonded to a highly electronegative atom of one molecule is attracted to two unshared electrons of another molecule |
| hydronium ion | an ion consisting of a proton combined with a molecule of water; H3O+ |
| hydroxide ion | the OH- ion |
| ion | an atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge |
| ionic bond | the attractive force between oppositely charged ions, which form when electrons are transferred from one atom to another |
| isotope | an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons |
| mass | a measure of the amount of matter in an object; a fundamental property of an object that is not affected by the forces that act on the object, such as the gravitational force |
| mass number | the sum of the numbers of protons and neutrons in the nucleus of an atom |
| matter | anything that has mass and takes up space |
| metabolism | the sum of all chemical processes that occur in an organism |
| molecule | a group of atoms that are held together by chemical forces |
| neutron | a subatomic particle that has no charge and that is located in the nucleus of an atom |
| nucleus | in physical science an atom's central region, which is made up of protons and neutrons |
| orbital | a region in an atom where there is a high probability of finding electrons |
| oxidation reaction | a chemical reaction in which a reactant loses one or more electrons such that the reactant becomes more positive in charge |
| pH scale | a range of values that are used to express the acidity or alkalinity of a system; 1-6=acidic, 7=neutral, 8-14=alkaline |
| polar | describes a molecule in which the positive and negative charges are separated |
| product | a substance that forms in a chemical reaction |
| poton | a subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of protons in the nucleus is the atomic number, which determines the identity of an element |
| reactant | a substance that participates in a chemical reaction |
| redox reaction | a reaction in which electrons are transferred between atoms; also known as an oxidation-reduction reaction |
| reduction reaction | a chemical change in which electrons are gained, either by the removal of oxygen, the addition of hydrogen, or the addition of electrons |
| saturated solution | a solution that cannot dissolve any more solute under the given conditions |
| solute | in a solution, the substance that dissolves in the solvent |
| solution | a homogeneous mixture throughout which two or more substances are uniformly dispered |
| solvent | in a solution, the substance in which the solute dissolves |