Chapter 2 & 3 - The Chemical Context of Life & Water and Life Flashcards
anything that takes up space and has mass
Matter
substance that cannot be broken down to other substances by chemical reactions
element
substance consisting of two or more different elements combined in a fixed ratio
compound
elements that an organism needs to live a healthy life and reproduce
essential elements
required by an organism in only minute quantities
trace elements
smallest unit of matter that still retains the properties of an element
atom
number of protons, which is unique to each element
atomic number
total number of protons and neutrons in the nucleus of an atom
mass number
the total mass of an atom
atomic mass
different atomic forms of the same element
isotopes
the nucleus decays spontaneously, giving off particles and energy
radioactive isotope
fixed rate at which a parent isotope decays into its daughter isotope (the time it takes for 50% of the parent isotope to decay)
half-life
process where scientists measure the ratio of different isotopes and calculate how many half-lives have passed since an organism was fossilized or a rock was formed
radiometric dating
the capacity to cause change, by doing work
energy
the energy that matter possesses because of its location or structure
potential energy
outer electrons in an atom
valence electrons
the outermost electron shell
valence shells
the 3D space where an electron is found 90% of the time
orbital
interactions usually result in atoms staying close together, held by attractions
chemical bonds
sharing of a pair of valence electrons by two atoms
covalent bonds
two or more atoms held together by covalent bonds
molecule
a pair of shared electrons
single bond
bonding capacity of an atom (equals number of electrons required to complete the atoms’s outermost shell
valence
the attraction of a particular atom for the electrons of a covalent bond
electronegativity
bond where electrons are shared equally in a covalent bond because they have the same electronegativity
nonpolar covalent bond
bond where an atom is bonded to a more electronegative atom, the electrons are not shared equally
polar covalent bond
oppositely charged atoms (or molecules)
ions
positively charged ion
cation
negatively charged ion
anion
bond where cations and anions attract each other
ionic bond
compounds formed by ionic bonds
ionic compounds or salts
noncovalent attraction between a hydrogen and an electronegative atom
hydrogen bond
individually weak and occur only when atoms and molecules are very close together
van der Waals interactions
the making and breaking of chemical bonds, leading to changes in the composition of matter
chemical reactions
starting materials in a chemical reaction
reactants
resulting materials in a chemical reaction
products
the point at which the reactions offset one another exactly
chemical equilibrium
molecule where its overall charge is unevenly distributed
polar molecule
hydrogen bonds hold the substance together
cohesion
measure of how difficult it is to stretch or break the surface of a liquid
surface tension
clinging of one substance to another
adhesion
energy of motion
kinetic energy
kinetic energy associated with the random movement of atoms or molecules (TOTAL kinetic energy)
thermal energy
represents the AVERAGE kinetic energy of the molecules in a body of matter, regardless of volume
temperature
thermal energy in transfer from one body of matter to another
heat
amount of heat it takes to raise the temp of 1g of water by 1 degree Celsisus
calorie (cal)
the amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1 degree Celsius
specific heat
quantity of heat a liquid must absorb for 1g of it to be converted form liquid to gaseous state
heat of vaporization
as a liquid evaporates, the surface of the liquid that remains behind cools down
evaporative cooling
a liquid that is completely homogenous mixture of tow or more substances
solution
dissolving agent of a solution
solvent
substance that is dissolved
solute
solution in which the solute is dissolved in water
aqueous solution
sphere of water molecules around each dissolved ion
hydration shell
any substance that has an affinity for water (WATER LOVING)
hydrophilic
substances that are nonionic and nonpolar that seem to repel water
hydrophobic
sum of the masses of all the atoms in a molecule
molecular mass
represents an exact number of objects (6.02 x 10 ^23)
mole (mol)
the number of moles of solute per liter of solution
molarity
a single proton with a charge of 1+
hydrogen ion (H+)
when a water molecule loses a proton and now has a charge of 1 -
hydroxide ion (OH–)
the proton binds to the other water molecule, which now has 3 hydrogens
hydronium ion (H3O-)
substance that increases the hydrogen ion concentration of a solution
acid
a substance that reduces the hydrogen ion concentration of a solution
base
The _____ of a solution is defined as the negative logarithm (base 10) of the H+ ion concentration
pH
substance that minimizes changes in the concentrations of H+ and OH– in a solution
buffer
when CO2 dissolves in seawater, it reacts with water to form carbonic acid which lowers the ocean pH
ocean acidification
