Chapter 2 Vocab Flashcards
anything that takes up space and has mass
matter
any substance that cannot be broken down to any other substance by chemical reaction
element
a substance consisting of two or more different elements combined in a fixed ratio
compound
a chemical element required for an organism to survive, grow and reproduce
essential elements
an element indispensible for life but required in extremely minute amounts
trace elements
the smallest unit of matter that retains the properties of an element
atom
a subatomic particle having no electrical charge (electrically neutral) with a mass of about 1.7x 10 -24 g, found in the nucleus of an atom
neutrons
a subatomic particle with a single positive electrical charge, with a mass of about 1.7 x 10 -24g, found in the nucleus of an atom
protons
a subatomic particle with a single negative electrical charge and a mass of about 1/2000 that of a neutron or proton, One or more electrons move around the nucleus of an atom
electrons
An atom’s dense central core. containing protons and neutrons
atomic nucleus
a measure of mass for atoms and subatomic particles; the same as the atomic mass unit, amu
dalton
the number of protons in the nucleus of an atom, unique for each element and designated by a subscript
atomic number
the sum of the number of protons and neutrons in an atom’s nucleus
mass number
the total mass of an atom, which is the mass in grams of 1 mole of the atom
atomic mass
one of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass
isotopes
an isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy
radioactive isotope
The capacity to cause change, especially to do work ( to move matter against an opposing force)
energy
the energy that matter possesses as a result of its location or spatial arrangement
potential energy
an energy level of electrons at a characteristic average distance from the nucleus of an atom
electron shells
an electron in the outer most electron shell
valence electrons
the outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom
valence shell
an attraction between two atoms resulting from sharing of outer shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells
chemical bonds
a type of strong chemical bond in which two atoms share one or more pairs of valence electrons
covalent bond
a single covalent bond; the sharing of a pair of valence electrons by two atoms
single bond
a double covalent bond; the sharing of two pairs of valence electrons by two atoms
double bond
the bonding capacity of a given atom; the number of covalent bonds an atom can form usually equals the number of unpaired electrons in its outermost (valence) shell
valence
the attraction of a given atom for the electrons of a covalent bond
electronegativity
a type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity
nonpolar covalent bond
a covalent bond between atoms that differ in electronegativity. the shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
polar convalent bond
an atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge
ion
a positively charged ion
cation
a negatively charged ion
anion
a chemical bond resulting from the attraction between oppositely charged ions
ionic bond
a compound resulting from the formation of an ionic bond; also called a salt
ionic compounds aka salts
a type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule
hydrogen bond
weak attractions between molecules or parts of molecules that results from the transient local partial charges
van der Waals interactions
a starting material in a chemical reaction
reactants
a material resulting from a chemical reaction
products
in a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction so that the relative concentrations of the reactants and products do not change with time
chemical equilibrium
a molecule (such as water) with an uneven distribution of charges in different regions of the molecule
polar molecule
the linking together of like molecules, often by hydrogen bonds
cohesion
the clinging of one substance to another, such as water to plant cell walls, by means of hydrogen bonds
adhesion
, a measure of how difficult it is to stretch or break the surface of a liquid
surface tension
the energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter
kinetic energy
kinetic energy due to the random motion of atoms and molecules; energy on its most random form (see also heat)
thermal energy
a measure in degrees of the average kinetic energy (thermal energy) of the atoms and molecules in a body of matter
temperature
thermal energy in transfer from one body of matter to another
heat
the amount of heat energy required to raise the temperature of 1g of water by 1 degree c; also the amount of heat energy that 1 g of water releases when it cools by 1 degree c. The CALORIE with a CAPITAL C usually used to indicate the energy content of food, is a kilocalorie.
calorie (cal)
a thousand calories; the amount of heat energy required to raise the temperature of 1 kg of water by 1 degree c
kilocalorie (kcal)
a unit of energy: 1 J = 0.239 cal; 1 cal = 4.184 J
joule (J)
the amount of heat that must be absorbed or lost by 1 g of a substance to change its temperature by 1 degree c
specific heat
the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to gaseous state
heat of vaporization
the process in which the surface of an object becomes cooler during evaporation, a result of the molecules with the greatest kinetic energy changing from the liquid to the gaseous state
evaporative cooling
a liquid that that is a homogeneous mixture of two or more substances
solution
the dissolving agent of a solution. water is the most versatile solvent known
solvent
a substance that is dissolved in a solution
solute
a solution in which water is the solvent
aqueous solution
the sphere of water molecules around a dissolved ion
hydration shell
having an affinity for water
hydrophilic
having no affinity for water; tending to coalesce and form droplets in water
hydrophobic
the sum of the masses of all the atoms in a molecule; sometimes called molecular weight
molecular mass
the number of grams of a substance that equals its molecular weight in daltons and contains Avogadro’s number of molecules
mole (mol)
the common measure of solute concentration, referring to the number of moles of solute per liter of solution
molarity
a single proton with a charge of 1+. The dissociation of a water molecule (H2O) leads to the generation of a hydroxide ion (OH-) and a hydrogen ion (H+); in water H+, is not found alone but associates with a water molecule to form a hydronium ion
hydrogen ion (H+)
a water molecule that has lost a proton OH-
hydroxide ion (OH-)
a water molecule that has an extra proton bound to it
hydronium ion (H3O+)
a substance that increases the hydrogen ion concentration of a solution
acid
a substance that reduces the hydrogen ion concentration of a solution
base
a measure of hydrogen ion concentration equal to -log [H+] and ranging in value from 0 to 14
pH
a solution that contains a weak acid and its corresponding base. A buffer minimizes changes in pH when acids or bases are added to the solution
buffer
