Chapter 4 - Chemical Basis Of Life

Front 1

Define: Matter

Back 1

Anything that occupies space and has mass

Front 2

Define: Element

Back 2

Pure substance that can not be broken down into other substances by chemical or physical means

Front 3

Define: Trace Element

Back 3

Element critical to health that makes up less than 0.01% of body mass

Front 4

Define: Compound

Back 4

Substance containing 2 or more elements chemically combined in a fixed ratio

Front 5

Define: Atom

Back 5

Smallest particle of an element

Front 6

Define: Proton

Back 6

Subatomic particle with a single unit of positive electric charge

Front 7

Define: Electron

Back 7

Subatomic particle with a single unit of negative electric charge

Front 8

Define: Neutron

Back 8

Subatomic particle that has no charge (is electrically neutral)

Front 9

Define: Nucleus

Back 9

In an atom, the central core that contains protons and neutrons

Front 10

Define: Atomic Number

Back 10

Number of protons in an atom's nucleus; is unique for each element

Front 11

Define: Isotope

Back 11

One of several forms of an element, each containing the same number of protons in their atoms but a different number of neutrons

Front 12

Define: Radioactive Isotope

Back 12

Isotope in which the nucleus decays (breaks down) over time, giving off radiation in the form of matter and energy

Front 13

Define: Ionic Bond

Back 13

Chemical bond that occurs when an atom transfers an electron to another atom

Front 14

Define: Ion

Back 14

Atom that has become electrically charged as a result of gaining or losing an electron

Front 15

Define: Covalent Bond

Back 15

Chemical bond that forms when 2 atoms share electrons

Front 16

Define: Molecule

Back 16

2 or more atoms held together by covalent bonds

Front 17

Define: Chemical Reaction

Back 17

Breaking of old and formation of new chemical bonds that result in new substances

Front 18

Define: Reactant

Back 18

Starting material for a chemical reaction

Front 19

Define: Product

Back 19

Material created as a result of a chemical reaction

Front 20

Define: Polar Molecule

Back 20

Molecule in which opposite ends have opposite electric charges

Front 21

Define: Hydrogen Bond

Back 21

Bond created by the weak attraction of a slightly positive hydrogen atom to a slightly negative portion of another molecule

Front 22

Define: Cohesion

Back 22

Tendency of molecules of the same kind to stick to one another

Front 23

Define: Adhesion

Back 23

Attraction between unlike molecules

Front 24

Define: Thermal Energy

Back 24

Total amount of energy associated with the random movement of atoms and molecules in a sample of matter

Front 25

Define: Temperature

Back 25

Measure of the average energy of random motion of particles in a substance

Front 26

Define: Solution

Back 26

Uniform mixture of 2 or more substances

Front 27

Define: Solvent

Back 27

Substance in a solution that dissolves the other substance and is present in the greater amount

Front 28

Define: Solute

Back 28

Substance in a solution that is dissolved and is present in a lesser amount

Front 29

Define: Aqueous Solution

Back 29

Solution in which water is the solvent

Front 30

Define: Acid

Back 30

Compound that donates H⁺ ions to an aqueous solution and measures less than 7 on the pH scale

Front 31

Define: Base

Back 31

Compound that removes H⁺ ions from an aqueous solution and that measures more than 7 on the pH scale

Front 32

Define: pH Scale

Back 32

A range of numbers used to describe how acidic or basic a solution is; ranges from 0 (most acidic) to 14 (most basic)

Front 33

Define: Buffer

Back 33

Substance that maintains a fairly constant pH in a solution by accepting H⁺ ions when their levels rise and donating H⁺ ions when their levels fall

Front 34

What is a chemical formula?

Back 34

Tells you the number and types of atoms in a molecule

Front 35

What is a structural formula?

Back 35

Indicates how atoms in a molecule are linked by bonds