Unit 1.1 - Water

Question 1

What type of molecule is water and why?

Answer 1

Polar, as it has a positive electrical charge on the hydrogen end and a negative electrical charge on the oxygen end

Question 2

What do you call the uneven distribution of charge that water molecules have?

Answer 2

Dipole

Question 3

What do you call the fact that water molecules stick together due to their polar nature?

Answer 3

Cohesion

Question 4

What do you call the bonds formed between water molecules?

Answer 4

Hydrogen bonds

Question 5

How do you represent the bonds between water molecules?

Answer 5

Dotted lines

Question 6

Describe hydrogen bonds

Answer 6

-Weak compared to covalent and ionic bonds
-So numerous in water gives them unique properties making them essential to life

Question 7

Name all of waters unique properties

Answer 7

-Surface tension
-Cohesion
-Adhesion
-Acting as a solvent
-Thermal properties (2)
-Transparency
-Density of ice
-Metabolite

Question 8

How does surface tension work?

Answer 8

The top layer of water has fewer hydrogen bonds than the body, making it stronger as the bond energy is shared between fewer hydrogen bonds, giving it a higher surface tension

Question 9

Cohesion

Answer 9

Water attracts itself

Question 10

Adhesion

Answer 10

Water attracts other cells

Question 11

What are the names of the vessels in trees that cohesion tension allows water to travel up them? What do these include?

Answer 11

Xylem vessels, unbroken chains of water molecules

Question 12

How does cohesion help us?

Answer 12

Cohesion tension is where the attraction between water molecules allows water to be transported in long columns up the xylem vessels in trees.

Question 13

Transpiration

Answer 13

The loss of water vapour through the stomata of plants, cooling it down as water is moved from the roots to the leaves

Question 14

How does a plant cool down?

Answer 14

Through transpiration, where the loss of water vapor through the stomata cools it down as water is moved from the roots to the leaves

Question 15

What is another process that helps trees get the water they need?

Answer 15

Adhesion, where because of their polar nature, water molecules attract the cellulose in the walls of the xylem vessels, allowing water to ‘climb’ up them, through the process of capillarity

Question 16

What’s the term for water ‘climbing’ up the xylem vessels by adhesion with cellulose?

Answer 16

Capillarity

Question 17

Which substance in the walls of the xylem vessels does water bind to through adhesion?

Answer 17

Cellulose

Question 18

Why do water particles attract charged particles?

Answer 18

They’re dipoles

Question 19

How does water act as a polar solvent?

Answer 19

As they’re dipoles, they attract charged particles such as ions and other polar molecules like glucose, which then dissolve in water allowing chemical reactions to happen in the solution created. The solute is fully dissolved as all ions are surrounded by the water molecules to keep them in a solution.

Question 20

What’s the phrase for the heat needed for turning liquid into vapour?

Answer 20

Latent heat of evaporation

Question 21

How does latent heat of evaporation work?

Answer 21

Water molecules draw heat energy from their surroundings in order to break free of the hydrogen bonds. This cools down the body as sweat evaporates, creating a cooling effect as the average energy remaining of the water molecules decreases, giving them a lower temperature.

Question 22

Define specific heat capacity

Answer 22

The energy required to raise the temperature of 1kg of any material by 1 degree Celsius

Question 23

Two thermal properties of water

Answer 23

1- High latent heat of evaporation
2-High specific heat capacity

Question 24

Why is water having a high specific heat capacity beneficial?

Answer 24

A lot of heat is required to raise the water temperature, which prevents large fluctuations in its temperature, so the temperature of aquatic environments remains stable. Orgainisms don’t have to endure extreme temperatures and enzymes within our cells work effectively as the body (70% water!) temperature is kept close to optimum for enzyme activity

Question 25

Why is water being transparent useful?

Answer 25

-Maintains ecosystems underwater
-Light can pass through so that plants can photosynthesise

Question 26

How does the density of ice benefit anything?

Answer 26

Less than the density of liquid water…..
-Floats on top, prevents the loss of heat underneath
-Water doesn’t freeze all the way to the bottom
-Aquatic animals and plants can survive under the ice in a relatively stable environment

Question 27

What type of reactions is water involved in as a metabolite?

Answer 27

Biochemical

Question 28

Examples of biochemical reactions that water is involved in

Answer 28

Hydrolysis, condensation, reactant of photosynthesis

Question 29

Hydrolysis

Answer 29

Water breaks one or more chemical bonds in a chemical reaction in a cell

Question 30

What type of solvent is water?

Answer 30

Polar solvent

Question 31

How are charges on water written and why?

Answer 31

d+ and d- as they’re so small

Question 32

Which of waters properties links it to the fact that it’s a good transport medium?

Answer 32

As a solvent

Question 33

Example of water acting as a transport medium in animals

Answer 33

Plasma transports dissolved substances

Question 34

2 examples of water acting as a transport medium in plants

Answer 34

-Minerals in the xylem vessels
-Sucrose and amino acids in the Phoelem

Question 35

What kind of molecules do not dissolve in water? Include an example of one

Answer 35

Non-polar molecules like lipids

Question 36

Which one of waters properties makes it a good transport medium?

Answer 36

It’s a polar solvent

Question 37

3 examples of water being a good transport medium due to it being a polar solvent

Answer 37

1- Plasma in animals for dissolved substances
2- Minerals in xylem vessels
3- Sucrose and amino acids in the phoelem

Question 38

What does latent heat of vaporisation actually mean?

Answer 38

A lot of energy is required to change water from a liquid to a vapour

Question 39

What to xylem vessels look like under a longitudinal section?

Answer 39

Repeated lines or rings across

Question 40

What does the loss of water do in the xylem?

Answer 40

Places tension on the water column

Question 41

What type of instrinsic protein is used during active transport?

Answer 41

Carrier