lecture 1- water and life

Question 1

what does hypertonic mean

Answer 1

low water concentration and high solute concentration

Question 2

what does hypotonic mean

Answer 2

high water concentrations and low solute concentration

Question 3

what is the link between hypotonic solutions and cell walls

Answer 3

cell walls protect the cell from rupturing when placed in a hypotonic solution
by osmosis the water would enters and the cell would swell and burst
(animal cells will rupture when left in water)

Question 4

what are four (4) properties of water that contribute to life on earth

Answer 4

cohesive behaviour
ability to moderate temperature
expansion upon freezing
versatility as a solvent

Question 5

what is cohesion

Answer 5

h bonds holding water molecules together

Question 6

what is adhesion

Answer 6

attraction between different substances (ex. water and cell wall)

Question 7

what is surface tension

Answer 7

measure of how hard it is to break the surface of a liquid

Question 8

explain water’s surface tension

Answer 8

water’s surface tension is weirdly high due to the h bonds between the surface molecules and the lower molecules

Question 9

characteristics of water regarding temperature

Answer 9

absorbs heat from warm air
releases heat to cold air
can absorb and release heat with little change to its own temperature

Question 10

what happens temperature wise when you break the h bonds in water

Answer 10

it heats the water and cools the air

Question 11

what happens temperature wise when you form the h bonds in water

Answer 11

cools water and heats the air

Question 12

what is water called due to its regulation of temperature (give ex of other similar substance)

Answer 12

temperature buffer
blood also does this

Question 13

what is thermal motion

Answer 13

the kinetic energy associated with the random motion of molecules

Question 14

what is temperature

Answer 14

measure of energy that represents the average kinetic energy of molecules

Question 15

what is heat

Answer 15

transfer of thermal energy from one body of matter to another

Question 16

what is a calorie

Answer 16

amount of heat required to raise temperature of 1g of water by 1C (celsius)

Question 17

how much is 1 joule in cal

Answer 17

1 J = 0.239 cal
1 cal = 4.184 J

Question 18

what is specific heat

Answer 18

amount of heat that must be absorbed or released to get 1g of a substance to gain/lose 1 celsius

Question 19

water’s specific heat

Answer 19

1 cal/g/C (high)

Question 20

what is heat of vaporization

Answer 20

heat a liquid must absorb for 1g to be converted to gas

Question 21

what is evaporative cooling

Answer 21

as a liquid evaporates its remaining surface cools (stabilizes temperature)

Question 22

what are water’s characteristics concerning density

Answer 22

water is the densest at 4C
at 0C ice expands and gains density
ice is less dense than water (more ordered/stable h bonds) so it floats instead of sinking (which would kill every living thing)

Question 23

what is the hydration shell

Answer 23

water molecules covering ions and molecules when they are put in water

Question 24

how does water dissolve nonpolar molecules

Answer 24

if the molecule has ionic/polar sections the hydration shell will start dissolving it there

Question 25

what is a dynamic equilibrium

Answer 25

equilibrium where components constantly change between reactants and products

Question 26

range of pH in biological fluids

Answer 26

6-8
blood 7.35-7.45

Question 27

what is a buffer

Answer 27

weak acid + conjugate base
minimizes changes in pH

Question 28

what is ocean acidification

Answer 28

oceans absorb CO2 generated by humans forming carbonic acid = oceans are more acidic

Question 29

result of ocean acidification

Answer 29

unbalance in chemical balance of oceans, rivers and lakes
threatens coral reefs