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44 terms

biology chapter 2 sec 1 - 3 vocab

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matter
anything that has mass and takes up space
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
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
atom
the smallest unit of an element that maintains the chemical properties of that element
nucleus
the part of the eukaryotic nucleus where ribosomal RNA is synthesized
proton
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
neutron
a subatomic particle that has no charge and that is located in the nucleus of an atom
atomic number
the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
mass number
the sum of the numbers of protons and neutrons in the nucleus of an atom
electron
a subatomic particle that has a negative charge
orbital
a region in an atom where there is a high probability of finding electrons
isotope
an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
compound
a substance made up of atoms of two or more different elements joined by chemical bonds
chemical bond
the attractive force that holds atoms or ions together
covalent bond
a bond formed when atoms share one or more pairs of electrons
molecule
a group of atoms that are held together by chemical forces; a molecule is the smallest unit of matter that can exist by itself and retain all of a substance's chemical properties
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
polar
describes a molecule in which the positive and negative charges are separated
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
cohesion
the force that holds molecules of a single material together
adhesion
the attractive force between two bodies of different substances that are in contact with each other
capillarity
the attraction between molecules that results in the rise of a liquid in small tubes
solution
a homogeneous mixture throughout which two or more substances are uniformly dispersed
concentration
the amount of a particular substance in a given quantity of a mixture, solution, or ore
saturated solution
a solution that cannot dissolve any more solute under the given conditions
aqueous solution
a solution in which water is the solvent
hydroxide ion
the OH- ion
hydronium ion
an ion consisting of a proton combined with a molecule of water; H3O+
acid
any compound that increases the number of hydronium ions when dissolved in water; acids turn blue litmus paper red and react with bases and some metals to form salts
base
any compound that increases the number of hydroxide ions when dissolved in water; bases turn red litmus paper blue and react with acids to form salts
pH Scale
a value that is used to express the acidity or alkalinity (basicity) of a system; each whole number on the scale indicates a tenfold change in acidity; a pH of 7 is neutral, a pH of less than 7 is acidic, and a pH of greater than 7 is basic
buffer
a solution made from a weak acid and its conjugate base that neutralizes small amounts of acids or bases added to it
energy
the capacity to do work
chemical reaction
the process by which one or more substances change to produce one or more different substances
reactant
a substance or molecule that that participates in a chemical reaction
product
a substance that forms in a chemical reaction
metabolism
the sum of all chemical processes that occur in an organism
activation energy
the minimum amount of energy needed to start a chemical reaction
catalyst
a substance that changes the rate of a chemical reaction without being consumed or changed significantly
enzyme
a type of protein or RNA molecule that speeds up metabolic reactions in plant and animals without being permanently changed or destroyed
redox reaction
a reaction in which electrons are transferred between atoms; also known as oxidation reduction reaction
oxidation reaction
chemical reaction in which a reactant loses one or more electrons such that the reactant becomes a more positive charge
reduction reaction
a chemical change in which electrons are gained , either by the the removal of oxygen, the addition of hydrogen, or the addition of of electrons