ch 2 chemical foundations of life

Question 1

what is the simplest, most common element?

Answer 1

hydrogen

Question 2

how many protons, neutrons, and electrons does oxygen have?

Answer 2

8

Question 3

how many protons, neutrons, and electrons does carbon have?

Answer 3

6

Question 4

what is the approximate mass of a single proton or neutron?

Answer 4

1 dalton

Question 5

what are isotopes?

Answer 5

atoms of the same element that have different atomic mass numbers due to different numbers of neutrons

Question 6

What are ions?

Answer 6

charged atoms

Question 7

Is hydrogen flammable?

Answer 7

yes

Question 8

Why is iron very useful?

Answer 8

it can exist in multiple charged states

Question 9

how many naturally occurring elements are there?

Answer 9

90

Question 10

What elements make up 96.3% of humans?

Answer 10

C, H, O, N

Question 11

What are characteristics of cations?

Answer 11

they have fewer electrons than protons and are positively charged

Question 12

what are the characteristics of anions?

Answer 12

they have more electrons than protons and are negatively charged

Question 13

What determines an element’s chemical properties?

Answer 13

its interactions between valence electrons of other atoms

Question 14

what are redox reactions?

Answer 14

electrons are transferred from one atom to another

Question 15

what is oxidation?

Answer 15

the loss of an electron

Question 16

what is reduction?

Answer 16

the gaining of an electron

Question 17

what are molecules?

Answer 17

atoms held together in a stable association

Question 18

when do covalent bonds form?

Answer 18

when atoms share two or more valence electrons

Question 19

when are covalent bonds stronger than others?

Answer 19

single bond < double bond < triple bond < etc.

Question 20

what compound is the cell membrane made of?

Answer 20

hydrocarbons

Question 21

is the cell membrane polar or non-polar?

Answer 21

non-polar

Question 22

what conducts electricity better? sea water or tap water

Answer 22

sea water

Question 23

why is water often thought to conduct electricity?

Answer 23

it is not the water itself but the dissolved solutes in the water that conduct

Question 24

What are non-polar covalent bonds?

Answer 24

bonds where there is an equal sharing of electrons

Question 25

What are polar covalent bonds?

Answer 25

bonds where there is an unequal sharing of electrons

Question 26

how are ionic bonds formed?

Answer 26

they are formed by the attraction of oppositely charged ion

Question 27

what are chemical reactions?

Answer 27

the formation of or breaking of chemical bonds

Question 28

why do cold-blooded animals eat so much less than warm blooded animals?

Answer 28

because to maintain a constant body temperature takes a large amount of energy

Question 29

What is this chemical reaction? 6H2O + 6CO2 —> C6H12O6 + 6O2

Answer 29

photosynthesis

Question 30

What is this chemical reaction? C6H12O6 + 6O2 —> 6H2O + 6CO2

Answer 30

cellular respiration

Question 31

what are hydrogen bonds?

Answer 31

weak attractions between the partially negative oxygen of one water molecule and the positive hydrogen of a different water molecule

Question 32

What holds an H2O molecule together?

Answer 32

polar covalent bonds

Question 33

What bond connects H2O molecules to each other?

Answer 33

hydrogen bonds

Question 34

What is the universal solvent?

Answer 34

water

Question 35

what is cohesion?

Answer 35

when water molecules stick to other water molecules by hydrogen bonding

Question 36

what is adhesion?

Answer 36

when water molecules stick to other polar molecules by hydrogen bonding

Question 37

What causes capillary action?

Answer 37

adhesive forces exceeding cohesive forces between water molecules

Question 38

What is the calorie of heat?

Answer 38

the amount of energy needed to get 1g of H2O to rise 1 degree celsius

Question 39

How much less dense is water in its solid state than in its liquid state?

Answer 39

9%

Question 40

What can dissolve polar molecules and ions by forming neutral barriers around them?

Answer 40

water

Question 41

are hydrophilic molecules charged or not charged?

Answer 41

charged

Question 42

Are hydrophobic molecules charged or not charged?

Answer 42

not charged

Question 43

what causes hydrophobic molecules to aggregate or assume certain shapes?

Answer 43

water

Question 44

what is the basis of the pH scale?

Answer 44

Hydrogen ions

Question 45

if something has a greater hydrogen ion (H^+1) concentration, does it have a lower or higher pH?

Answer 45

lower pH (acidic)

Question 46

if something has a lesser hydrogen ion (H^+1) concentration, does it have a lower or higher pH?

Answer 46

higher pH (basic)

Question 47

what does it mean that water has a high specific heat?

Answer 47

a large amount of energy is needed to change the temperature

Question 48

What does it mean that water has a high heat of vaporization?

Answer 48

evaporation of water from a surface requires a large amount of energy

Question 49

water can interact with something as long as it has a ______.

Answer 49

charge

Question 50

what is the pH of pure water?

Answer 50

7

Question 51

what is the pH of blood?

Answer 51

slightly higher than 7

Question 52

what is an acid?

Answer 52

a chemical that releases protons/ H^+1 ions

Question 53

what is a base?

Answer 53

a chemical that accepts protons/ H^+1 ions

Question 54

What accepts and releases H^+1 ions as necessary to keep a constant pH?

Answer 54

buffer

Question 55

what do most biological buffers normally consist of?

Answer 55

a pair of molecules, one acid and one base

Question 56

what are neutral atoms?

Answer 56

atoms that have the same number of protons and electrons (inert elements/noble gasses)

Question 57

how many of the naturally occurring elements are found in living organisms in substantial amounts?

Answer 57

12

Question 58

what is the octet rule?

Answer 58

atoms want a full outer orbital; they must either lose or gain electrons to do so

Question 59

what is electronegativity?

Answer 59

an atom’s affinity for electrons

Question 60

within a water molecule, the bonds between oxygen and hydrogen are highly polar because…

Answer 60

oxygen is partially negative and hydrogen is partially positive

Question 61

what do differences in electronegativity dictate in covalent bonds?

Answer 61

how electrons are distributed

Question 62

nonpolar covalent bonds = ________ sharing of electrons

Answer 62

equal

Question 63

polar covalent bonds = ________ sharing of electrons

Answer 63

unequal

Question 64

How are ionic bonds formed?

Answer 64

They are formed by the attraction of oppositely charged ions; the electron is taken not shared

Question 65

What happens during chemical reactions?

Answer 65

The breaking or formation of chemical bonds

Question 66

What can influence wether or not a chemical reaction happens?

Answer 66

Temperature, concentration of reactants and products, and the availability of a catalyst