H5

Question 1

what does pH stand for?

Answer 1

potential of hydrogen (it is the number of hydrogen ions)

Question 2

what is the pH of sea water

Answer 2

between 8,1-8,2

Question 3

how does the pH influence corals?

Answer 3

Corals are affected by the amount of dissolved co2: more dissolved co2 can ultimately reduce the calcium carbonate available for corals to make their calcareous skeleton.

Question 4

which other organisms can pH influence? (4)

Answer 4

1. coccolithophores
2. foraminifera
3. crustaceans
4. other shellfish/animals (calcareous house builders)

Question 5

what is water?

Answer 5

H2O, 2 hydrogen atoms and one oxygen atom chemically bound into one molecule

Question 6

chemical properties of H and O atoms

Answer 6

1. hydrogen has one proton in the nucleus, with one electron around it
2. oxygen has eight protons in the nucleus, with eight electrons around it

Question 7

solid form of water: atoms and molecules

Answer 7

ice. the molecules hardly move and stay on the same place

Question 8

fluid form of water: atoms and molecules

Answer 8

water. the molecules move quickly and far from each other. movement is free compared to each other

Question 9

gas form of water: atoms and molecules

Answer 9

water vapor. the molecules move very quickly and very far. they are full of energy. they are, in most part, independent

Question 10

what type of structure is a water molecule?

Answer 10

dipole. it is asymmetric

Question 11

is oxygen a negative or positive charge?

Answer 11

negative charge

Question 12

is hydrogen a negative or positive charge?

Answer 12

positive

Question 13

cluster forming of water molecules

Answer 13

1. cumulative positive charge
2. cumulative negative charge
3. bound through hydrogen bonds

Question 14

water has a high heat capacity

Answer 14

1. a lot of energy is needed to heat 1 gram of water by 1 degree C
2. how higher the temperature, how less H2O clusters there are

Question 15

temp determines density:

Answer 15

1. atoms and molecules move quicker

2. density (mass/volume) decreases; there is less mass (atoms) in the same volume

Question 16

molecular structure of ice: density… how does ice float?

Answer 16

1. water molecules in ice are structured hexagonally
2. in the hexagon is an open space, whereby it is 8% less dense than water
3. fluid water has a lot of hydrogen compounds (waterstofverbindingen), whereby it is denser than ice
4. structured with covalent bonds.

ice is less dense than water, so it floats on the denser, fluid water

Question 17

dissolved substances in water (5)

Answer 17

1. salt
2. nutrients
3. gasses
4. trace elements
5. organic compounds

Question 18

average salt in sea water

Answer 18

35g salt by 1,000g sea water.
= 35 parts per thousand (ppt)
35 promille (means ppt)
35 = 3,5% of seawater is salt

Question 19

salinity variation

Answer 19

through percipitation (neerslag) and evaporation (verdamping)

Question 20

salt content in sea water

Answer 20

1. natrium and chloride cover together almost 86% dissolved salt in sea water
2. little variation over time –> therefore, conservative property of seawater

Question 21

nutrient content in sea water

Answer 21

1. small amount…measured in parts per million (ppm)

2. large variation over time –> therefore, nonconservative property of seawater

Question 22

gas content in sea water

Answer 22

nitrogen (stikstof) and noble gases are inert because they are chemically nonrecreative

Question 23

trace element content in sea water

Answer 23

1. very small amounts. measured in ppm or even parts per billion (ppb)
2. than to the small amount, trace elements can play a crucial role in life and death

Question 24

large complex molecules

Answer 24

1. fat
2. carbohydrates
3. hormones
4. proteins
5. vitamins

Question 25

where does salt in sea water come from?

Answer 25

1. erosion from land
2. reaction of lava with sea water
3. detached from stones through chemical reactions between stones and acid rain water

Question 26

how do we measure salinity?

Answer 26

1. refractometer (%)
2. multimeter (EGV)
3. measure chlorine (total halogens in sea water - chlorine, bromine, iodine and fluorine. salinity = 1,8065 x chlorineity)

Question 27

thermocline

Answer 27

exists where warm water (lower density) is next to cold water (higher density). temp and density change very quickly with thermocline. pole areas don’t have a thermocline, but temperate areas have thermoclines in different seasons as it is temperature dependent

Question 28

halocline

Answer 28

abrupt difference in salinity between surface sea water and deeper water. dependent on salinity

Question 29

pychnocline

Answer 29

abrupt difference in density between surface sea water and deeper water. dependent on density

Question 30

layers in sea water

Answer 30

surface water is lighter than deep water because it has a lower salinity and higher temperature (and thus, lower density)

Question 31

gases in the surface layer

Answer 31

a lot of oxygen through photosynthesis and diffusion from the atmosphere

Question 32

gases in the pycnocline layer

Answer 32

little oxygen at 150-1500m through large quantities of organisms respirating

Question 33

gases in the the deep sea

Answer 33

relatively large quantity of oxygen through the sinking of oxygen-rich cold surface water to the bottom

Question 34

more H+ ions dissolved means…

Answer 34

the more acidic the sea water

Question 35

ore OH- ions disolved means…

Answer 35

the more alkaline the sea water

Question 36

three forms of dissolved CO2 in the sea:

Answer 36

1. carbon dioxide (CO2)
2. bicarbonate (HCO3-)
3. carbonate (CO3ˆ2-)

Question 37

what is pH dependent on?

Answer 37

the amount of dissolved CO2 in sea water

Question 38

What happens when CO2 is dissolved in sea water?

Answer 38

It reacts to carbonic acid (koolzuur –> H2CO3) and then to bicarbonate and/or carbonate. Then the hydrogen ion comes free (H+)