Chapter 2 Terms

Front 1

chemistry

Back 1

the science of structure and interactions of matter

Front 2

matter

Back 2

anything that occupies space and has mass

Front 3

mass

Back 3

the amount of matter in any object. it does not change.

Front 4

weight

Back 4

the force of gravity acting on matter. it can change.

Front 5

chemical elements

Back 5

a substance that cannot be split into a simpler substance.
there are 117, and 92 occur naturally on earth.

Front 6

chemical symbol

Back 6

one or two letters of the element's name in english, latin, or another language.

Front 7

the major elements (4)

Back 7

oxygen, carbon, hydrogen, and nitrogen

Front 8

lesser elements (8)

Back 8

calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium, and iron.

Front 9

trace elements

Back 9

elements found in trace amounts that make a very small portion of the body's mass. example: iodine

Front 10

atoms

Back 10

the smallest units of matter that retain the properties and characteristics of the element.

Front 11

subatomic particles

Back 11

make up atoms. protons, neutrons, and electrons.

Front 12

nucleus of atom

Back 12

the dense central core where the protons and neutrons are.

Front 13

protons

Back 13

positively charged, all atoms of the same element have the same number of protons.

Front 14

neutrons

Back 14

neutral.

Front 15

electrons

Back 15

negatively charged

Front 16

electron shells

Back 16

areas surrounding the nucleus of an atom, where the electrons are likely to be.

Front 17

atomic number

Back 17

the number of protons in the nucleus of an atom.

Front 18

mass number

Back 18

the sum of an atom's protons and neutrons

Front 19

isotopes

Back 19

atoms of an element that have different numbers of neutrons, and therefore have different mass numbers.

Front 20

radioactive isotopes

Back 20

unstable isotopes who's nuclei decay into a stable configuration.

Front 21

half life of isotope

Back 21

the time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form.

Front 22

dalton (atomic mass unit)

Back 22

the standard unit of measuring the mass of atoms and their subatomic particles.

Front 23

atomic mass (atomic weight)

Back 23

the average mass of all of an element's naturally occuring isotopes.

Front 24

ion

Back 24

an atom that has a postive or negative charge because it has unequal numbers of protons and electons.

Front 25

ionization

Back 25

the process of giving up or gaining electrons.

Front 26

molecure

Back 26

two or more atoms sharing electrons.

Front 27

compound

Back 27

a substance that contains atoms of two or more different elements. most of the atoms in the body are joined into compounds.

Front 28

free radical

Back 28

an atom or group of atoms with an unpaired electron in the outermost shell.

Front 29

chemical bonds

Back 29

the forces that hold together the atoms of a molecule or compound.

Front 30

valance shell

Back 30

an atom's outermost shell.

Front 31

octet rule

Back 31

atoms will arrange themselves in a way that allows for eight valence electrons for each atom.

Front 32

ionic bond

Back 32

the force of attraction that holds ions with opposite charges together.

Front 33

anion

Back 33

a negatively charged ion

Front 34

cation

Back 34

a positively charged ion

Front 35

electrolyte

Back 35

an ionic compound that breaks apart into positive and negative ions in a solution.

Front 36

covalent bond

Back 36

two more more atoms sharing electrons rather than gaining or losing them

Front 37

nonpolar covalent bond

Back 37

two atoms sharing electrons equally

Front 38

polar covalent bond

Back 38

the sharing of electrons between atoms is unequal

Front 39

electronegativity

Back 39

the power an atom has to attract electrons to itself.

Front 40

hydrogen bond

Back 40

a hydrogen atom with a partial positive charge attracts the partial negative charge of neighboring electronegative atoms.

Front 41

surface tension

Back 41

a measure of the difficulty of stretching or breaking the surface of a liquid.

Front 42

chemical reaction

Back 42

a reaction when new bonds from or old bonds break between atoms.

Front 43

reactants

Back 43

the starting substances of a chemical reaction.

Front 44

products

Back 44

the ending substances of a chemical reaction.

Front 45

metabolism

Back 45

all the chemical reactions occuring in the body

Front 46

energy

Back 46

the capacity to do work

Front 47

potential energy

Back 47

energy stored by matter due to it's position

Front 48

kinetic energy

Back 48

energy associated with matter in motion

Front 49

chemical energy

Back 49

a form of potential energy that is stored in the bonds of compounds and molecules

Front 50

law of conservation of energy

Back 50

energy cannot be created or destroyed, but can be converted from one form to another

Front 51

exergonic reactions

Back 51

release more energy than they absorb

Front 52

endergonic reactions

Back 52

absorb more energy than they release

Front 53

activation energy

Back 53

the energy required to start a reaction

Front 54

catalysts

Back 54

chemical compounds that speed up chemical reactions

Front 55

synthesis reactions

Back 55

when two or more atoms, ions, or molecules combine to form new and larger molecules

Front 56

anabolism

Back 56

a blanket term for all of the synthesis reactions that happen in the body

Front 57

decomposition reactions

Back 57

split up larger molecules into smaller atoms, ions, or molecules

Front 58

catabolism

Back 58

a blanket term for all of the decomposition reactions that happen in the body

Front 59

exchange reactions

Back 59

reactions consisting of both synthesis and decomposition reactions. ex: AB + CD = AD + BC

Front 60

reversible reaction

Back 60

the reaction's products can revert to the original reactants

Front 61

oxidation

Back 61

the loss of electrons

Front 62

reduction

Back 62

the gain of electrons

Front 63

inorganic compounds

Back 63

usually lack carbon and are structurally simple. they may have either ionic or covalent bonds.

Front 64

organic compounds

Back 64

always contain carbon and usually contain hydrogen. they always have covalent bonds.

Front 65

solvent

Back 65

what dissolves the substance in a solution. usually there is more solvent than solute in a solution.

Front 66

the solute

Back 66

the substance that is dissolved in a solution

Front 67

hydrophillic

Back 67

water loving

Front 68

hydrophobic

Back 68

water fearing

Front 69

hydrolysis reactions

Back 69

decomposition reaction in which water molecules are added

Front 70

dehydration synthesis reaction

Back 70

when two smaller molecules join to form a larger molecule, and one of the products formed is water

Front 71

mixture

Back 71

a combination of elements or compounds that are physically blended together but not bound by chemical bonds

Front 72

colloid

Back 72

different from a solution because of the difference in particles. the particles are large enough to scatter light.

Front 73

mole

Back 73

a mole is the amount of any substance that has a mass in grams, equal to the sum of the atomic masses of all it's atoms.

Front 74

disassociate

Back 74

when inorganic acids, bases, or salts dissolve in water, they separate into ions and become surrounded by water molecules

Front 75

acid

Back 75

a substance that dissolves into one or more hydrogen ions. an acid is also referred to as a proton doner because of hydrogen's single positive charge.

Front 76

base

Back 76

disassociates into hydroxide ions. removes hydrogen ions from a solution, and is therefore a proton acceptor.

Front 77

salt

Back 77

when dissolved in water, disassociates into cations and anions, neither of which are hydrogen ions or hydroxide ions.

Front 78

acidic solution

Back 78

a solution with a pH less than 7

Front 79

basic (alkaline) solution

Back 79

a solution with a pH greater than 7

Front 80

buffer systems

Back 80

systems that function to convert strong acids or bases into weak acids or bases

Front 81

buffers

Back 81

the chemical compounds that can convert strong acids or bases into weaker ones

Front 82

carbonic-acid-bicarbonate buffer system

Back 82

carbonic acid can act as a weak acid, and bicarbonate ion can act as a weak base. Hence, this buffer system can compensate for either an excess or a shortage of hydrogen ions.