[2] Vocabulary - The Chemical Context of Life Flashcards
cation
a positively charged ion
scatter plot
a graph in which each piece of data is represented by a point, but individual points are not connected by lines
solution
homogenous mixture of two or more substances
chemical equilibrium
rate of forward reaction equals rate of reverse reaction, concentrations of reactants and products do not change over time
anion
a negatively charged ion
proton
a subatomic particle with a single positive electrical charge (mass approximately 1.7x10^-24 grams)
atomic number
the number of protons in the nucleus of an atom, unique for each element and designated by a subscript
mass number
the total number of protons and neutrons in an atom’s nucleus
chemical reaction
the making and breaking of chemical bonds, leading to changes in the composition of matter
matter
anything that takes up space and has mass
energy
the capacity to cause change, especially to do work (to move matter against an opposing force)
compound
a substance consisting of two or more different elements combined in a fixed ratio
trace element
an element indispensable for life but required in extremely minute amounts
pH
a measure of hydrogen ion concentration equal to -log[H+] and ranging in value from 0 to 14.
polar molecule
a molecule (such as water) with an uneven distribution of charges in different regions of the molecule
temperature
a measure in degrees of the average thermal energy of the atoms and molecules in a body of matter
atomic mass
mass of an atom, equal to mass in grams of 1 mole
essential element
A chemical element required for an organism to survive, grow, and reproduce.
acid
substance that increases hydrogen ion concentration (pH=0-6.9)
evaporative cooling
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.
regression line
a line that best describes the behavior of a set of data
ocean acidification
The process by which the pH of the ocean is lowered (made more acidic) when excess CO2 dissolves in seawater and forms carbonic acid (H2CO3).
thermal energy
Kinetic energy due to the random motion of atoms and molecules; energy in its most random form.
ionic bond
a chemical bond resulting from the attraction between oppositely charged ions.
electron
a subatomic particle with a single negative electrical change and a mass about 1/2000 that of a neutron or proton. One or more electrons move around the nucleus of an atom.
mole (mol)
The number of grams of a substance that equals its molecular weight in daltons and contains Avogadro’s number of molecules.
hydrogen ion
the cation H+ of acids consisting of a hydrogen atom whose electron has been transferred to the anion of the acid
ionic compound
A compound resulting from the formation of an ionic bond; also called a salt.
kinetic energy
the energy associated with the relative motion of objects–moving matter can perform work by imparting motion to other matter
hydrogen bond
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
reactant
a starting material in a chemical reaction
base
a substance that reduces the hydrogen ion concentration of a solution, a substance with a high pH
valence electron
an electron in the outermost electron shell
adhesion
the clinging of one substance to another, such as water to plant cell walls, by means of hydrogen bonds
buffer
a solution that contains a weak acid and its corresponding base to minimize changes in pH when acids or bases are added to the solution
nonpolar covalent bond
a type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity
polar 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.
element
any substance that cannot be broken down to any other substance by chemical reactions
specific heat
the amount of heat that must be absorbed or lost for 1g of a substance to change its temperature by 1C
neutron
a subatomic particle having no electrical charge (electrically neutral) with a mass of about 1.7 x 10-24g, found in the nucleus of an atom
molecular mass
the sum of the masses of all the atoms in a molecule; sometimes called molecular weight
product
a material resulting from a chemical reaction
valence
the bonding capacity of a given atom; the number of covalent bonds an atom can form, which usually equals the number of unpaired electrons in its outermost (valence) shell
salt
a compound resulting from the formation of an ionic bond; also called an ionic compound
surface tension
a measure of how difficult it is to stretch or break the surface of a liquid
molecule
two or more atoms held together by covalent bonds
radioactive isotope
an isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy
chemical bond
an attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.
hydrophilic
having an affinity for water
molarity
a common measure of solute concentration, referring to the number of moles of solute per liter of solution
kilocalorie
a thousand calories; the amount of heat energy required to raise the temperature of 1 kg of water by 1 C
electron shell
an energy level of electrons at a characteristic average distance from the nucleus of an atom
hydroxide ion
a water molecule that has lost a proton; OH-
covalent bond
a type of strong chemical bond in which two atoms share one or more pairs of valence electrons
van der Waals interactions
weak attractions between molecules or parts of molecules that result from transient local partial charges
heat of vaporization
the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state
hydration shell
the sphere of water molecules around a dissolved ion
ion
an atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge
joule
a unit of energy: 1 J = 0.239 cal; 1 cal = 4.184 J
electronegativity
the attraction of a given atom for the electrons of a covalent bond
solvent
the dissolving agent of a solution. Water is the most versatile solvent known
hydrophobic
having no affinity for water; tending to coalesce and form droplets in water
atomic nucleus
an atom’s dense central core, containing protons and neutrons
valence shell
the outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom
heat
thermal energy in transfer from one body of matter to another
dalton
a measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu
potential energy
the energy that matter possesses as a result of its location or spatial arrangement (structure)
cohesion
the linking together of like molecules, often by hydrogen bonds
atom
the smallest unit of matter that retains the properties of an element
double bond
a double covalent bond; the sharing of two pairs of valence electrons by two atoms
solute
a substance that is dissolved in a solution
isotope
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
single bond
a single covalent bond; the sharing of a pair of valence electrons by two atoms
aqueous solution
a solution in which water is the solvent
calorie (cal)
The amount of heat energy required to raise the temperature of 1 g of water by 1°C; also the amount of heat energy that 1 g of water releases when it cools by 1°C. The Calorie (with a capital C), usually used to indicate the energy content of food, is a kilocalorie.
hydronium ion
a water molecule that has an extra proton bound to it; H3O+, commonly represented as H+
