APES Vocabulary Chapter 2

Matter

Anything that occupies space and has mass.

Mass

A measurement of the amount of matter an object contains.

Atom

The smallest particle that can contain the chemical properties of an element.

Element

A substance composed of atoms that cannot be broken down into smaller, simpler components.

Periodic table

A chart of all chemical elements currently known, organized by their properties.

Molecule

A particle that contains more than one atom.

Compound

A molecule containing more than one element.

Atomic number

The number of protons in the nucleus of a particular element.

Mass number

A measurement of the total number of protons and neutrons in an element.

Isotopes

Atoms of the same element with different numbers of neutrons.

Radioactive decay

The spontaneous release of material from the nucleus of radioactive isotopes.

Half-life

The times it takes for one-half of an original radioactive parent atom to decay.

Covalent bond

The bond formed when elements share electrons.

Ionic bond

A chemical bond between two ions of opposite charges.

Hydrogen bond

A weak chemical bond that forms when hydrogen atoms that are covalently bonded to one atom are attracted to another atom on another molecule.

Polar molecule

A molecule in which one side is more positive and the other side is more negative.

Surface tension

A property of water that results from the cohesion of water molecules at the surface of a body of water and that creates a sort of skin on the water's surface.

Capillary action

A property of water that occurs when adhesion of water molecules to a surface is stronger than cohesion between the molecules.

Acid

A substance that contributes hydrogen ions to a solution.

Base

A substance that contributes hydroxide ions to a solution.

pH

The number that indicates the relative strength of acids and bases in a substance.

Ocean acidification

An increase in the acidity of the oceans.

Chemical reaction

A reaction that occurs when atoms separate from molecules or recombine with other molecules.

Law of conservation of matter

A law of nature stating that matter cannot be created or destroyed; it can only change form.

Inorganic compound

A compound that does not contain the element carbon or contains carbon bound to elements other than hydrogen.

Organic compound

A compound that contains carbon-carbon and carbon-hydrogen bonds.

Carbohydrate

A compound composed of carbon, hydrogen, and oxygen atoms.

Protein

A critical component of living organisms made up of a long chain of nitrogen-containing organic molecules known as amino acids.

Nucleic acid

Organic compounds found in all living cells.

DNA (deoxyribonucleic acid)

A nucleic acid, the genetic material that contains the code for reproducing the components of the next generation, and which organisms pass on to their offspring.

RNA (ribonucleic acid)

A nucleic acid that translates the code stored in DNA, which makes possible the synthesis of proteins.

Lipid

A smaller organic biological molecule that does not mix with water.

Cell

A highly organized living entity that consists of the four types of macromolecules and other substances in a watery solution, surrounded by a membrane.

Energy

The ability to do work or transfer heat.

Joule

The amount of energy used when a 1-watt electrical device is turned on for 1 second

Power

The rate at which work is done.

Electromagnetic radiation

A form of energy emitted by the Sun that includes, but is not limited to, visible light, ultraviolet light, and infrared energy.

Photon

A massless packet of energy that carries electromagnetic radiation at the speed of light.

Potential energy

Stored energy that has not been released.

Chemical energy

Potential energy stored in chemical bonds.

Kinetic energy

The energy of motion.

Temperature

The measure of the average kinetic energy of a substance.

First law of thermodynamics

A physical law which states that energy can neither be created nor destroyed but can change from one form to another.

Second law of thermodynamics

The physical law stating that when energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes.

Energy efficiency

The ratio of the amount of energy expended in the form you want to the total amount of energy that is introduced into the system.

Energy quality

The ease with which an energy source can be used for work.

Entropy

Randomness in a system.

Open system

A system in which exchanges of matter or energy occur across system boundaries.

Closed system

A system in which matter and energy exchanges do not occur across boundaries.

Input

An addition to a system.

Output

A loss from a system.

Systems analysis

An analysis to determine inputs, outputs, and changes in a system under various conditions.

Steady state

A state in which inputs equal outputs, so that the system is not changing over time.

Negative feedback loop

A feedback loop in which a system responds to a change by returning to its original state, or by decreasing the rate at which the change is occuring.

Positive feedback loop

A feedback loop in which change in a system is amplified.

Adaptive management plan

A plan that provides flexibility so that managers can modify it as changes occur.