Chapter 3: Water and life

Question 1

chemical properties of water

Answer 1

1.) polar covalent bond between one oxygen and two hydrogen atoms
–hydrogen (positive) oxygen(negative)
2.) hydrogen bonds between water molecules

Question 2

The four (4) important characteristics/characters of water.

Answer 2

–cohesion of water molecules
–moderations of temperature by water
–insulation from floating ice
–the solvent of life

Question 3

cohesion of water molecules

Answer 3

by hydrogen bonds among water molecules.
–hydrogen bonds are transient in liquid but abundant.
1.) transport of water to the top of plants.
2.) surface tension /surfactant or soap reduces surface tension.

Question 4

cohesion

Answer 4

between water molecules

Question 5

adhesion

Answer 5

binding different molecules

Question 6

what is kinetic energy?

Answer 6

energy of motion

Question 7

what is heat?

Answer 7

measure of the total amount of kinetic energy. due to molecular motion in a body of matter

Question 8

what is temperature?

Answer 8

measurement of intensity of heat.
–average: kinetic energy of the molecules in a body of matter/regardless of volume.

Question 9

what is thermal energy?

Answer 9

total kinetic energy of the molecules in a body of matter.

Question 10

moderations of temperature by water:

Answer 10

kinetic energy
heat
temperature
thermal energy
celsius vs. fahrenheit
calorie (cal)
Joule (J)
specific heat

Question 11

what is a calorie or (cal)?

Answer 11

amount of heat required to raise the temp. of 1 gram of water by 1 degree celsius.

Question 12

what is a joule (J)?

Answer 12

1 cal = 4.184 J

Question 13

what is specific heat?

Answer 13

amount of heat that must be absorbed or lost for 1g of that substance to change its temp by 1 degree celsius.

Question 14

what does water serve as?

Answer 14

reservoir of Energy

Question 15

is water resistant to temperature change?

Answer 15

yes

Question 16

how much of earth surface is covered by water?

Answer 16

1/3 or about 71%

Question 17

does a hydrogen bond work as a cushion to change in energy?

Answer 17

yes

Question 18

what are the advantages of higher specific heat energy of water to biosystem?

Answer 18

stable temp. of atmosphere
—relativley easy to maintain stable body temp.

Question 19

heat of vaporization

Answer 19

amount of heat a liquid must absorb for 1 gram of it be converted from the liquid to the gaseous state.

Question 20

how does water have higher heat of vaporization?

Answer 20

by hydrogen bonds

Question 21

what are the advantages to bio-systems?

Answer 21

-sweat to body
-evaporation from plant surface
evaporation from surface of water stabilizes water temp of the earth.

Question 22

insulation from floating ice?:

Answer 22

ice is less dense than water
-formation of permanent hydrogen among four water molecules
–floatation of ice provides insulation to the body of water below
—-allows life to live under the water
—-provides habitat to animals (polar bears and seals)

Question 23

specific heat

Answer 23

compared to the water rather than just the energy needed

Question 24

solution

Answer 24

liquid that is homogenous mixture of 2 or more substances

Question 25

solvent

Answer 25

dissolving agent of solution

Question 26

solute

Answer 26

substance that is dissolved

Question 27

protein

Answer 27

amino acids

Question 28

water is a versitile solvent:

Answer 28

property comes from polarity of water --NaCl in water ---polarity of substances also provide water solubility -----lysosomes in water

Question 29

hydrophilic

Answer 29

has affinity for water --can be dissolved or suspended in water

Question 30

colloid

Answer 30

suspension of particles in water ---cotton is hydrophilic but not dissolved

Question 31

hydrophobic

Answer 31

-repels -non-polar and non ionic substances ---cell membrane is made of non-polar fatty acids inside of the structure -----solute concentration in aquenous solution.

Question 32

mole

Answer 32

quantity of particles fo any tupe equal to Avagadro's # or 6.02X10>23

Question 33

molar weight

Answer 33

the sum of the atomic weight of all the atoms in molecule

Question 34

molar solution

Answer 34

solution that contains one mole of solute per liter of solution

Question 35

acid

Answer 35

donate hydrogen: release hydrogen in solution

Question 36

strong acids

Answer 36

fully dissolved (HCl, H2SO4)

Question 37

weak acids

Answer 37

partially dissolved (acetic acids, citric acid).

Question 38

base

Answer 38

accept hydrogen

Question 39

strong base

Answer 39

fully dissolved

Question 40

weak bases

Answer 40

partially dissolved

Question 41

neutral

Answer 41

equal concentration of H+ and OH- in a solution

Question 42

reversible reaction

Answer 42

ionization of weak acids and bases are usually reversible (CH3 COOH <===> CH3COO- + H+

Question 43

[H+]

Answer 43

molecular concentration of H+

Question 44

pH scale:

Answer 44

--measure of hydrogen in concentration pH value is "negative logarithm of the hydrogen ion concentration in moles per liter pH = -log10 [H+]

Question 45

when pH is 7, what happens?

Answer 45

both the H+ and OH- are at a concentration of 10-7 molar

Question 46

when pH is 8 is 8 what happens?

Answer 46

it is 10 -8 molar for H+ and 10 -6 molar for OH

Question 47

what does the higher # of pH mean?

Answer 47

the greater the OH- concentration and the lower the H+

Question 48

buffer solutions

Answer 48

solution that minimizes pH fluctuate --when acids or bases are added ex. H2CO3 <---> H+ + HCO3

Question 49

why are buffers important?

Answer 49

they are important in the regulation of the internal environments of organisms

Question 50

what are buffers?

Answer 50

weak acids or weaker bases

Question 51

what keeps pH near neutral?

Answer 51

many important biological buffers transition around pH 7.

Question 52

Acid Rain:

Answer 52

pH of regular rain is 5.6; CO2 +H2O---H+ +HCO- 3 ---rain lower than pH 5.6 is this. sulfur oxides, nitrogen oxides

Question 53

ocean acidification

Answer 53

pH of present day sea water is o.1 pH unit lower than of past. --will drop another 0.3-0.5 pH unit by the end of this century.