week 5 - physical and chemical properties of seawater

Question 1

properties of seawater (8 things)

Answer 1

1. water
2. temperature
3. salinity
4. density
5. carbon dioxide
6. acidity and alkalinity (pH)
7. the carbonate buffer system
8. chemical residence time

Question 2

salinity and pH of seawater

Answer 2

salinity of 35 PSU and pH of 7.5 to 8.4

Question 3

polarity

Answer 3

has a positive charge on one end of a molecule and negative charge on the other
- results in high latent heats of melting and vaporization

Question 4

hydrogen bonds during heating (melting)

Answer 4

some break away from each other

Question 5

hydrogen bonds in ice

Answer 5

lots of packed bonds

Question 6

hydrogen bonds during vaporization (gas)

Answer 6

all of the bonds break

Question 7

how is seawater different from regular water?

Answer 7

seawater has a high salinity
- proportion of ions is constant no matter where you get the water from

Question 8

how to find total salinity

Answer 8

1.80555 x ionic abundance

Question 9

what is temperature in relation to seawater

Answer 9

a measure of the amount of heat stored in the ocean
- affects density (the higher the temperature of the water, the lower the density)
- oceans store a lot of energy because of the high heat capacity

Question 10

salinity

Answer 10

the salt content of seawater that is expressed in the concentration of ions in seawater

Question 11

how does the salinity of seawater increase?

Answer 11

whenever pure water is removed by evaporation or the formation of ice

Question 12

how does the salinity of seawater decrease?

Answer 12

when water is added by precipitation or the melting of ice

Question 13

inorganic components in seawater

Answer 13

1. chloride (CI-)
2. sodium (NA+)
3. sulfate (SO42)
4. magnesium (MG2+)
5. calclium (CA2+)
6. potassium (K+)

Question 14

factors that change the salinity of seawater

Answer 14

1. evaporation of water and formation of ice increase salinity
2. precipitation and ice melting (adding water) decreases salinity

Question 15

with increasing salinity (3 things)

Answer 15

1. density of water increases
2. boiling point of water increases
3. freezing point of water decreases

Question 16

density in relation to seawater

Answer 16

1. coldest waters are usually the most dense
2. high density is favored by low temperature and high salinity

Question 17

CO2 in relation to seawater

Answer 17

1. highly soluble in seawater because it creates carbonic acid

Question 18

dissolved organic carbon (DIC)

Answer 18

when carbonic acid dissociates to form hydrogen and bicarbonate ions, which then dissociates to form hydrogen and carbonate ions
- most of carbon dioxide in the oceans is stored in bicarbonate ions

Question 19

acids

Answer 19

any compounds that when dissolved in water, releases hydrogen ions (H+, also called protons) which increases their concentration in solution

Question 20

what makes pH neutral

Answer 20

when concentration of protons and hydrogen ions are equal in pure water

Question 21

what happens when we dissolve acid in water?

Answer 21

the hydrogen ion concentration will increase as the acid dissociates

Question 22

alkaline substance (base)

Answer 22

dissociates in water, releasing hydroxyl ions (OH-) into the solution

Question 23

pH system

Answer 23

ranges from 0 to 14
- pure water has a neutral pH with a value of 7
- acidic solutions have extra H+ and has a value of LESS than 7
- alkaline (basic solutions) has pH values GREATER than 7
- when concentration goes down 1 level, the concentration goes up by ten

Question 24

what happens when you add acid to water?

Answer 24

H reacts with bicarbonate and makes carbonic acid

Question 25

what happens when you add alkaline to water?

Answer 25

OH- reacts with carbonic acid which makes bicarbonate

Question 26

chemical residence time

Answer 26

the average length of time an element spends in the ocean between its addition and removal amount of element in ocean/elements rate of removal (or addition from the ocean)