Chapter 2 Flashcards
define matter
anything that occupies space and has mass
define mass
the quantity of matter an object has
define elements
substances that cannot be broken down chemically into simpler kinds of matter
define atom
the simplest particle of an element that retains all of the properties of that element
define nucleus
makes up the bulk of the mass of the atom and consists of two kinds of subatomic particles, a proton and neutron.
define atomic number
the number of protons in an atom
define mass number
the total number of protons and neutrons of the atom
define electrons
negatively charged particles that balances the amount of protons
define orbital
a three-dimensional region around a nucleus that indicates the probable location of an electron
define isotopes
atoms of the same element that have a different number of neutrons
define compounds
atoms of two or more elements in fixed proportions
define chemical bonds
the attractive forces that hold atoms together
define covalent bond
a covalent bond forms when two atoms share one or more pairs of electrons
define molecule
the simplest part of a substance that retains all of the properties of that substance and can exist in a free state
define ion
an atom or molecule with an electrical charge
define ionic bond
positive and attractive bond
states of matter: solid
atoms or molecules are more closely linked together than of a gas or liquid, moves less rapidly, maintains a fixed volume and shape
define chemical reaction
one or more substances change to produce one or more different substances
define metabolism
all of the chemical reactions that occur in an organism
define activation energy
the amount of energy needed to start a reaction
define catalyst
reduce the amount of activation energy needed for a reaction to take place
define enzyme
a protein or RNA molecule that speeds up the metabolic reactions without being permanently changed or destroyed
define redox reactions
reactions in which electrons are transferred between atoms. a reactant gains one or more electrons
define polar bond
uneven distribution of charge
define hydrogen bond
the force of attraction between a a hydrogen molecule with partial or full negative charge.
define cohesion
an attractive force that holds molecules of a single substance together
define adhesion
the attractive force between two particles of different substance, such as water molecules and glass molucules
define capillary
the attraction between molecules that results in the rise of the surface of a liquid when in contact with a solid
states of matter: ice
open spaces, low density
define solution
a mixture in which one or more substances are uniformly distributed in another subtance
define solute
a substance dissolved in the solvent
when solvent
the substance in which tge sikute is dissolved
define concentration
the amount of solute dissolved in a fixed amount of this solution
define saturated solution
one in which no more solute can dissolve
define aqueous solution
solutions in which water is the solvent
define acid
number of hydronium ions in a solution is greater than the number of hydroxide ions
define base
the solution contains more hydroxide ions than hydronium ions
define buffers
chemical substances that neutralize small amounts of either an acid or base added to a solution
