3.1.7 Water Flashcards

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1
Q

In a water molecule, there are 2…atoms and 1… atom

A

Hydrogen
Oxygen

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2
Q

In a water molecule, there are 2…atoms and 1… atom

A

Hydrogen
Oxygen

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3
Q

In a water molecule the hydrogen atoms have a slight …. charge

A

Positive

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4
Q

In a water molecule the oxygen atom has a slight … charge

A

Negative

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5
Q

In a water molecule the covalent bonds between the hydrogen and oxygen atoms are described as being p…

A

Polar

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6
Q

In a water molecule the….are polar

A

Covalent bonds between the oxygen and hydrogen atoms

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7
Q

In a water molecule the hydrogen atoms have a slight positive charge and the oxygen atom has a slight negative charge because…

A

An oxygen atom has 8 protons but a hydrogen atom only has 1 proton
So the shared electrons are slightly pulled towards the positive protons in the oxygen

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8
Q

The forces of attraction between different water molecules are called…

A

Hydrogen bonds
(As the slightly positively charged hydrogen atoms from one water molecule are attracted to the slightly negatively charged oxygen atom of another water molecule and vice versa)

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9
Q

Hydrogen bonds refer to…

A

The forces of attraction between different water molecules

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10
Q

True or false, individual hydrogen bonds (forces of attraction between different water molecules) are strong

A

False
Each hydrogen bond is weak but because there are so many of them overall they are strong

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11
Q

7 key properties of water

A

Cohesion
Solvent
Transparent
Metabolite
High specific heat capacity
High latent heat of vaporisation
Ice floats on top of water (as ice is less dense than water)

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12
Q

Cohesion is where water molecules stick together due to…

A

Hydrogen bonds

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13
Q

Cohesion is where water molecules….due to hydrogen bonds

A

Stick together

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14
Q

….is where water molecules stick together due to hydrogen bonds

A

Cohesion

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15
Q

The biological significance of cohesion as a property of water is that…

A

It supports continuous columns of water in the xylem
It provides surface tension to support small insects on the surface of the water

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16
Q

The biological significance of transparency as a property of water is that…

A

It allows light to penetrate through so aquatic plants can photosynthesise

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17
Q

The biological significance of ice floating on top of water (ice is less dense than water) as a property of water is that

A

Lakes freeze from the top down maintaining aquatic life beneath

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18
Q

The biological significance of high specific heat capacity as a property of water is that…

A

Water buffers changes in temperature making aquatic environments more hospitable

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19
Q

The biological significance of metabolite as a property of water is that…

A

Water plays a role in chemical reactions e.g hydrolysis reactions and condensation reactions

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20
Q

The biological significance of metabolite as a property of water is that…

A

Water plays a role in chemical reactions e.g hydrolysis reactions and condensation reactions

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21
Q

The biological significance of solvent as a property of water is that…

A

Metabolic reactions can occur
Substances can be transported

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22
Q

The biological significance of high latent heat of vaporisation as a property of water is that…

A

Water provides a cooling effect through evaporation e.g sweating

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23
Q

There are no bonds between water and…which leads to surface tension

A

Air

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24
Q

Surface tension supports…..that live on the surface of the water so supports life and provides a habitat

A

Small insects e.g pondskaters

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25
Q

Adhesion is where water molecules stick to other ..

A

Polar molecules
(Different types of polar molecules stick to each other)

26
Q

In the xylem, water molecules stick to the xylem walls which is known as …

A

Adhesion
(As the water molecules are sticking to other polar molecules)

27
Q

Adhesion vs cohesion

A

Cohesion is where water molecules stick to each other due to hydrogen bonds
Adhesion is where water molecules stick to other polar molecules (e.g water molecules sticking to the walls of the xylem)

28
Q

Water is a solvent which means that …. and…substances can dissolve in it

A

Polar
Ionic

29
Q

Ions can be dissolved in water in the… of cells in order to be transported

A

Cytoplasm
(As water is a solvent)

30
Q

At the top of a miniscus …occurs as the water molecules stick to the walls

A

Adhesion

31
Q

Oil doesn’t dissolve in water because….

A

It isn’t polar or ionic
(Only polar or ionic substances can dissolve in water)

32
Q

A condensation reaction is a chemical reaction where…

A

A water molecule is released when chemical bonds are formed between molecules

33
Q

In a condensation reaction is water released or needed

A

Released

34
Q

In a hydrolysis reaction is water released or needed

A

Needed

35
Q

A hydrolysis reaction is a chemical reaction where…

A

A water molecule is needed to break up a large molecule into smaller molecules

36
Q

In a condensation reaction a water molecule is released when…

A

Chemical bonds are formed between molecules

37
Q

In a hydrolysis reaction, a water molecule is needed to..

A

Break up a large molecule into smaller molecules

38
Q

Hydrolysis and condensation reactions are both examples of water as a m…

A

Metabolite

39
Q

Condensation vs hydrolysis reactions

A

Condensation= water molecule released (when bonds are FORMED between molecules)
Hydrolysis= water molecule needed (to BREAK up a large molecule into smaller molecules)

40
Q

Ice is…dense than water

A

Less
(So ice floats on water)

41
Q

Ice floats on water because it is… dense than water

A

Less

42
Q

True or false, as water freezes it expands

A

True

43
Q

As water freezes it expands because…

A

Water molecules are held further apart by hydrogen bonds
(So it becomes less dense)

44
Q

The biological significance of ice floating on water as a property of water is that lakes freeze top down maintaining….

A

Aquatic life beneath

45
Q

Ice floats on water so when the top part of the lake freezes it….the water beneath so that it remains unfrozen (which maintains the aquatic life beneath)

A

Insulates

46
Q

………is the property of water where water evaporates from a liquid to a gas and the process requires lots of energy in order to break the hydrogen bonds between the water molecules (this process carries energy away from the organism very quickly to cool them down)

A

High latent heat of vaporisation

47
Q

During sweating, energy (in the form of heat) is carried away from the organism very….

A

Quickly.
(This has a cooling effect)

48
Q

Evaporation requires lots of energy because….

A

The hydrogen bonds between water molecules need to be broken

49
Q

High… means that lots of energy is needed for liquid water to turn into a gas (this means that energy can be carried away from the organism very quickly which then acts as a cooling effect)

A

Latent heat of vaporisation

50
Q

2 thermal properties of water

A

High latent heat of vaporisation
High specific heat capacity

51
Q

Thermal property of water that involves a change of state

A

High latent heat of vaporisation (lots of energy needed to turn water from a liquid to a gas so energy is carried away from the organism very quickly which acts as a cooling effect)

52
Q

Thermal property of water that refers to liquid water only and doesn’t involve a change of state

A

High specific heat capacity

53
Q

Thermal property which means water is thermostable and a thermal buffer

A

High specific heat capacity

54
Q

High specific heat capacity means that lots of energy is needed to…

A

Raise temperature of 1kg of water by 1 degree

55
Q

Water is a thermal buffer (as a result of having a high specific heat capacity) which means that it resists changes to…

A

Temperature

56
Q

Water is a thermal buffer (as a result of having a high specific heat capacity) which means that it resists changes to…

A

Temperature

57
Q

High latent heat of vaporisation vs high specific heat capacity

A

High latent heat of vaporisation means lots of energy is needed to change state of water from liquid to gas- this means energy is carried away from the organism very quickly so the evaporation provides a cooling effect

High specific heat capacity means lots of energy is needed to raise temperature of 1kg of water by 1 degree so water acts as a thermal buffer (resists changes in temperature)- this makes aquatic environments more hospitable (better to live in)

58
Q

The biological significance of…means that water provides a cooling effect through evaporation e.g sweating

A

High latent heat of vaporisation

59
Q

The biological significance of…means that water buffers changes in temperature making an aquatic environment more hospitable

A

High specific heat capacity

60
Q

Water molecules are described as being polar because…

A

There is an uneven distribution of charge (the oxygen atom is slightly negative and the hydrogen atoms are slightly positive)
(The covalent bonds within the water molecule are also described as being polar)

61
Q

Water molecules are described as being…because there is an uneven distribution of charge (the hydrogen atoms have a slight positive charge and the oxygen atom has a slight negative charge)

A

Polar