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Bio101 Chpt 2
Campbell Biology101 Chapter 2 The Chemical Basis of Life
Term | Definition |
---|---|
Matter | Anything that takes up space. |
Element | Substance that can't be broken down to other substances by ordinary chemical means. |
Compound | A Substance consisting of two or more different elements combined in a fixed ratio. |
Trace Elements | Are essential but only in very small quantities. |
Proton | A subatomic particle with a single positive electrical charge. |
Electron | A subatomic particle with a single negative charge |
Neutron | Is electrically neutral; has no charge. |
Atomic Number | The number of protons an atom has. |
Mass Number | The sum of the number of protons and neutrons in its nucleus. |
Atomic Mass | Is equal to its mass number. |
Isotopes | An element that has the same number of protons and behave identically in chemical reactions, but they have different numbers of neutrons. |
Radioactive Isotope | Where a nucleus decays spontaneously, giving off particles and energy. |
Electron Shells | Depending on an elements atomic number, an atom may have one, two, or more of these surrounding the nucleus. |
Chemical Bonds | An attraction between two atoms resulting form a sharing of outer shell electrons or the presence of opposite charges on the atoms. |
Covalent Bond | The strongest kind of chemical bond; where two atoms share one or more pairs of outer shell electrons. |
Molecule | Two or more atoms held together by covalent bonds. |
Nonpolar Covalent Bond | Where electrons are shared equally between the atoms. |
Polar Covalent Bond | Unequal sharing of electrons. |
Polar Molecule | Has an unequal distribution of charges; negative at the oxygen and positive at each of the two hydrogen ends. |
Ion | An atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons. |
Ionic Bond | A chemical bond resulting form the attraction between oppositely charged ions. |
Hydrogen Bond | Weakest of all bonds. |
Chemical Reaction | The breaking and making of chemical bonds which lead to changes in the composition of matter. |
Surface Tension | A measure of how difficult it is to stretch or break the surface of a liquid. |
Heat | Amount of energy associated with the movement of atoms and molecules in the body of matter. |
Temperature | Measures the intensity of heat; the average speed of molecules rather the an the total amount of heat energy in a body of matter. |
Solution | Liquid consisting of a uniform mixture of two or more substances. |
Solvant | The dissolving agent (i.e. water). |
Salute | Substance being dissolved. |
Acid | A compound that donates hydrogen ions to solutions. H+ |
Base | A compound that accepts hydrogen ions and removes them from solution. OH- |
pH Scale | Describes how acidic or basic a solution is. |