Chapter 2: The Chemical Context of Life

Question 1

matter

Answer 1

anything that takes up space & has mass

Question 2

Element

Answer 2

substance that con’t be broken down to other substance by chemical reactions

Question 3

__, __, __, and __ makeup 96% of life

Answer 3

Carbon, Oxygen, Hydrogen, & Nitrogen

Question 4

Compound

Answer 4

substance consisting of 2 or more elements in a fixed ration

Question 5

Trace Elements

Answer 5

needed in minute elements

Question 6

atomic number

Answer 6

number of protons

Question 7

Mass Number

Answer 7

sum of protons & neutrons in nucleus

Question 8

Atomic Mass

Answer 8

atom’s total mass; approximated by mass #

Question 9

isotopes

Answer 9

same # of protons but diff # neutrons

Question 10

Radioactive Isotopes

Answer 10

give off particles & energy
- can sometimes lose protons => daughter (new) element

Question 11

Energy

Answer 11

capacity to cause change

Question 12

Potential Energy

Answer 12

energy that matter has bc of its location or structure
- electrons of atom differ in their amts of PE

Question 13

state of PE

Answer 13

energy level/electron shell

Question 14

Valence Electrons

Answer 14

electrons in outermost shell

Question 15

chemical behavior of an atom is determined by

Answer 15

valence electrons

Question 16

Types of Chemical Bonds

Answer 16

Covalent
Ionic
Hydrogen

Question 17

Chemical Bond

Answer 17

attractions that result in atoms staying close together

Question 18

Covalent

Answer 18

sharing electrons

Question 19

Ionic

Answer 19

one atom steals electrons

Question 20

Hydrogen

Answer 20

weakly donate electrons

Question 21

2 Types of Covalent Bonds

Answer 21

nonpolar
polar

Question 22

What is the strongest of all bonds?

Answer 22

covalent

Question 23

Electronegativity

Answer 23

an atom’s attraction for electrons in covalent bond (affinity)

Question 24

the more electronegative…

Answer 24

the stronger the atom pulls the electron(s) toward itself

Question 25

Nonpolar covalent

Answer 25

electrons shared equally

Question 26

Polar Covalent

Answer 26

one atom is slightly more electronegative => electrons not shared equally

Question 27

Ions are

Answer 27

atoms with a charge

Question 28

Ionic bond is

Answer 28

attraction between anion & cation

Question 29

Compounds are formed by

Answer 29

ionic bonds

Question 30

Ionic bonds are weak when

Answer 30

water is present

Question 31

Van der Waals Interactions

Answer 31

charge differences between molecules close in space => weak attraction

Question 32

Molecular shape

Answer 32

determined by positions of atom's valence orbitals

Question 33

Molecules with similar shapes can have

Answer 33

similar biological effects Ex: natural endorphin & morphine

Question 34

Chemical reaction leads to

Answer 34

new arrangement of atoms

Question 35

Reactants

Answer 35

starting molecules

Question 36

Products

Answer 36

final molecules

Question 37

Chemical Equilibrium

Answer 37

reached when the forward & reverse reaction rates are equal

Question 38

Chemical Reactions can be

Answer 38

reversible => products can become reactants