Chapter 2

Question 1

bioremediation

Answer 1

applications of chemical and biological knowledge to decontaminate polluted environments

Question 2

element

Answer 2

pure substance that cannot be broken down into simpler substances

Question 3

matter

Answer 3

anything that occupies space and has mass

Question 4

trace elements

Answer 4

elements that occur in very small amount in organisms

Question 5

atoms

Answer 5

smallest units that retain the chemical and physical properties of an element

Question 6

molecules

Answer 6

atoms combined chemically in fixed numbers and ratios

Question 7

formula

Answer 7

name of a molecule written in chemical shorthand

Question 8

compounds

Answer 8

molecules whose component atoms are different

Question 9

protons

Answer 9

positively charged particles in nucleus

Question 10

atomic number

Answer 10

number of protons in the nucleus of an atom

Question 11

neutrons

Answer 11

uncharged particles in the nucleus

Question 12

isotopes

Answer 12

an atom with the same number of protons but with a different number of neutrons

Question 13

dalton

Answer 13

standard unit of mass

Question 14

mass number

Answer 14

based on the total number of protons and neutrons in an atom

Question 15

radioactivity

Answer 15

giving off particles of matter and energy that can be detected

Question 16

radioisotope

Answer 16

unstable radioactive isotope

Question 17

tracers

Answer 17

isotopes used to label molecules so that they can be tracked as they pass biochemical reactions

Question 18

orbital

Answer 18

the region of space where the electron is most of the time

Question 19

energy levels/shells

Answer 19

regions of space where electrons are found

Question 20

valence electrons

Answer 20

electrons in the outermost energy level of an atom

Question 21

chemical bonds

Answer 21

when reactive elements combine into molecules

Question 22

ionic

Answer 22

results from electrical attractions between atoms that gain and lose valence electrons completely

Question 23

ions

Answer 23

charged particles

Question 24

cation

Answer 24

positively charged ion

Question 25

anion

Answer 25

negatively charged ion

Question 26

covalent bond

Answer 26

atoms sharing valence electrons

Question 27

electronegativity

Answer 27

measure of atom’s attraction for the electrons sharing in a bond

Question 28

nonpolar covalent bonds

Answer 28

electrons are shared equally

Question 29

polar covalent bonds

Answer 29

electrons are not shared equally

Question 30

polar associations

Answer 30

polar molecules aligning themselves with other polar molecules or ions

Question 31

nonpolar associations

Answer 31

excluded nonpolar molecules that clump together

Question 32

hydrophilic

Answer 32

associate readily with water

Question 33

hydrophobic

Answer 33

excluded by polar molecules

Question 34

hydrogen bond

Answer 34

when hydrogen atoms are in a covalent bond and then show some attraction to other ions or molecules

Question 35

van der waals forces

Answer 35

weakest forces that occur at very small distances because electrons accumulate by chance in one part of the molecule

Question 36

reactants

Answer 36

atoms or molecules entering a chemical reaction

Question 37

products

Answer 37

atoms or molecules leaving a reaction

Question 38

chemical equations

Answer 38

chemical reactions written in balanced form

Question 39

water lattice

Answer 39

structure of water that allows hydrogen bonds to constantly break and reform

Question 40

ice lattice

Answer 40

structure of ice that spaces the molecules farther apart decreasing the density

Question 41

specific heat

Answer 41

amount of energy required to increase the temperature of a given quantity of water

Question 42

calories

Answer 42

calorie refers to a kilocalroie

Question 43

heat of vaporization

Answer 43

required heat to break loose liquid water and form a gas

Question 44

cohesion

Answer 44

high resistance of water molecules to separation provided by hydrogen bonding lattice

Question 45

adhesion

Answer 45

molecules stick to walls of tubes by forming hydrogen bonds with charged polar groups in molecules that form the walls

Question 46

surface tension

Answer 46

forced created by the unbalanced bonding that places the surface water molecules under tension that makes them more resistant to separation than the underlying molecules

Question 47

bilayer

Answer 47

created by exclusion by water molecules of lipid molecules to associate into a second layer

Question 48

hydration layer

Answer 48

surface coat that reduces the tension between molecules or ions and promotes separation onto a solution; caused by water coating surfaces of other polar molecules

Question 49

solution

Answer 49

mixture when atoms are suspended individually separated by water molecules

Question 50

solvent

Answer 50

the dissolving agent of a solution

Question 51

solute

Answer 51

substance dissolved into solvent or water

Question 52

concentration

Answer 52

number of molecules or ions of a substance in a unit volume

Question 53

atomic weight

Answer 53

weight in grams equal to the mass number

Question 54

avogadros number

Answer 54

6.02 x 10^23

Question 55

molecular weight

Answer 55

sum of atomic weights of all the atoms in the molecule

Question 56

mole

Answer 56

6.02x10^23 molecules or atoms

Question 57

molarity

Answer 57

number of mole per liter

Question 58

dissociate

Answer 58

separate into the individual ions that make up a compound

Question 59

reversible

Answer 59

a reaction may go either to the left or right

Question 60

acids

Answer 60

proton donors that release h+ when dissolved in water

Question 61

bases

Answer 61

proton acceptors that reduce the H+ concentration of a solution

Question 62

acidity

Answer 62

determined by the h+ concentration

Question 63

buffers

Answer 63

substances that compensate for ph changes by absorbing or releasing h+