Chapter 2: The Chemistry of Life

Question 1

Acid

Answer 1

any substance that dissociates in water to increase the [H+] (and lower the pH)

Question 2

Adhesion

Answer 2

attraction of polar substances

Question 3

Amphipathic molecules

Answer 3

contain hydrophobic and hydrophilic regions; associate into highly organized structures in water

Question 4

Atom

Answer 4

smallest, stable components of cells; contain protons, neutrons, and electrons

Question 5

Atomic mass

Answer 5

sum of masses of protons and neutrons in an action

Question 6

Base

Answer 6

a substance that dissociates in water to decrease the [H+]

Question 7

Bohr model

Answer 7

proton in middle with electrons on appropriate ring of energy level

Question 8

Buffer

Answer 8

a substance that resists changes in pH

Question 9

Chemical bond

Answer 9

atoms in a molecule are joined by this bond

Question 10

Compound

Answer 10

when a molecule contains atoms of more than one element

Question 11

Covalent bond

Answer 11

two atoms share one or more pairs of valence electrons

Question 12

Cohesion

Answer 12

water molecules are attracted to one another

Question 13

Dalton

Answer 13

unit of mass

Question 14

Electron

Answer 14

negative charge

Question 15

Electronegativity

Answer 15

atoms differ in their affinity for electrons

Question 16

Element

Answer 16

substance consisting of one type of atom with the same number of protons

Question 17

Energy level

Answer 17

electrons have energy of position. When an atom absorbs energy, an electron moves to a higher energy level, farther from the nucleus. When an electron falls to lower energy levels, closer to the nucleus, energy is released.

Question 18

Evaporative cooling

Answer 18

ex.) sweat

Question 19

Heat of vaporization

Answer 19

amount of energy required to change 1 gram of substance from liquid to gas

Question 20

High specific heat

Answer 20

water has this quality and water heats up slowly and holds temperature longer

Question 21

Hydrogen bond

Answer 21

bonds between different water molecules

Question 22

Hydrophilic

Answer 22

“water-loving”; readily forms hydrogen bonds

Question 23

Hydrophobic

Answer 23

“water-fearing”; shrinks from contact with water

Question 24

Ice

Answer 24

it floats

Question 25

Ion

Answer 25

atom or molecule with a net electric charge due to the loss or gain of one or more electrons

Question 26

Ionic bond

Answer 26

opposite charges attract each other

Question 27

Isotope

Answer 27

atoms of same element that have different numbers of neutrons

Question 28

Mass

Answer 28

amount of substance

Question 29

Molecule

Answer 29

a group of atoms held together by energy in a stable association

Question 30

Neutron

Answer 30

neutral charge

Question 31

Nonpolar molecules

Answer 31

the affinity for electrons is obviously the same, and the electrons are equally shared

Question 32

Nucleus

Answer 32

contains protons and neutrons

Question 33

Octet rule

Answer 33

"rule of 8"; completely full outer energy levels

Question 34

Organic compounds

Answer 34

the majority of molecules that make up the body contain carbon. carbon, hydrogen, oxygen, nitrogen

Question 35

Oxidation

Answer 35

electrons lost, energy released

Question 36

pH

Answer 36

means "partial hydrogen"; increases 10-fold

Question 37

Polar

Answer 37

one positive charge and a complimentary negative charge

Question 38

Proton

Answer 38

positive charge

Question 39

Radioactive

Answer 39

nucleus tends to break up into elements with lower atomic numbers

Question 40

Reduction

Answer 40

electrons gained, energy stored

Question 41

Solute

Answer 41

dissolved in the solvent

Question 42

Solvent

Answer 42

the liquid in which a solute is dissolved to form a solution

Question 43

Solution

Answer 43

a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent)

Question 44

Surface tension

Answer 44

the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area

Question 45

Trace element

Answer 45

C, H, O, N, P, S, Na, K, Ca, Mg, Fe, and Cl

Question 46

Valence electron

Answer 46

electrons in the outermost energy level; determine an elements reactive properties

Question 47

5 properties of water

Answer 47

cohesion, high specific heat, high heat of vaporization, lower density of ice, solubility

Question 48

Heat of fusion

Answer 48

water has high heat of fusion because it resists change from liquid to solid state

Question 49

Water is the most dense when?

Answer 49

at 4 degrees Celsius, right before it freezes