Ch 12 - Properties of water

Question 1

How much of the earths land does water cover?

Answer 1

70%

Question 2

How much does water make up of the human body?

Answer 2

70%

Question 3

What are 4 physical properties of water

Answer 3

-is a polar molecule-freezes at 0 degrees-exissts in liquis form at 25 degrees-will boil at 100 degrees

Question 4

Define latent heat

Answer 4

Amount of energy needed to change a substance to a different state.

Question 5

What are the units for latent heat?

Answer 5

kJ mol-1, and Jkg-1

Question 6

What is the symbol for latent heat?

Answer 6

L

Question 7

Define latent heat fusion of water

Answer 7

The amount of energy required to change a fixed amount of water from a solid to a liquid state.

Question 8

What happens in the process of latent heat fusion of water

Answer 8

The bonds in the ice are broken enabling the water molecules to move around more freely

Question 9

What are the values for latent heat fusions?

Answer 9

6.02kJ energy is needed to change one mole of water from a solid to a liquid

Question 10

Define latent heat of vaporisation

Answer 10

Amount of energy hat is needed to change a fixed amount of water from a liquid to a gas.

Question 11

Does water have a high latent heat?

Answer 11

Yes

Question 12

Why is it that water has a high latent heat

Answer 12

Strong intermolecular forces between states

Question 13

What are the values for latent heat vaporisation?

Answer 13

40.7 mol (needed to vaporise one mole of water)

Question 14

What is perspiration and how does it involve latent heat vaporisation?

Answer 14

Perspiration is a way of removing unwanted heat from the body, .

Question 15

Define specific heat capacity

Answer 15

The amount of energy needed to raise one gram of substance by one degree

Question 16

The formula for specfic heat capacity

Answer 16

Q=mct

Question 17

What is the pattern with high specific heat capacity and energy?

Answer 17

The higher the specific heat capacity the more energy it will need to absorb to raise the temperature.

Question 18

What is waters specific heat

Answer 18

4.15

Question 19

What is ethanols specific heat

Answer 19

2.5

Question 20

Define density

Answer 20

The measure of amount of mass that is contained in a certain volume of substance

Question 21

Formula for density

Answer 21

d=m/v

Question 22

What are the units for density?

Answer 22

gcm-3 and kgm-3

Question 23

What is the official symbol for density?

Answer 23

p

Question 24

Is ice or liquid water more dense

Answer 24

Liquid water

Question 25

At what temperature is water at its densist

Answer 25

4 degrees celcius

Question 26

Does ice float on water

Answer 26

Yes

Question 27

What does the low density of ice mean?

Answer 27

It expands when frozen

Question 28

Does pure water conduct electricity

Answer 28

In the very slightest, however is described as a non-conductor

Question 29

Define self-ionisation

Answer 29

Water molecules reacting slightly with one another to produce a small amount of ions

Question 30

What bonds so water have?

Answer 30

dispersion and hydrogen

Question 31

What elements does the hydrogen bind to

Answer 31

Fluorine, nitrogen and oxygen

Question 32

Explain the strength of hydrogen bonding

Answer 32

No electrons left to shield one side as both of the hydrogens are drawn towards the oxygen, hence water can attract other molecules very closely resulting in a stronger bond.

Question 33

Do temperatures usually increase or decrease down a group?

Answer 33

increase due to having to break down larger molecules which require more energy.

Question 34

List ways the hydrogen bonding affects the properties of water

Answer 34

-High melting and boiling points-High latent heat (fusion and vaporisation)-High heat capacity-Ablitlity of water to dissolve other substances

Question 35

What is water also reffered to as in regards to solubility?

Answer 35

The universale solvent

Question 36

Are water moelcules polar or non-polar

Answer 36

POlar

Question 37

What is the rule to do with dissolving

Answer 37

like dissolves like

Question 38

Explain how water produces hydrated ions

Answer 38

Salt is placed in the water and the water surrounds the postiive and negative ions and pulls them apart

Question 39

List the behaviour of some substances in water

Answer 39

-some can remain undissolved-ionisation (polar molecules reacting with water to orm ions)-Ionic substances may dissociate-Other polar molecuels such as (suagr and ethanol) can still undergo disscation however the solution will not conduct electricty

Question 40

Do polar gases dissolve easily in water?

Answer 40

YEs e.g ammoinia gas and hcl gas

Question 41

Do non-polar gases dissolve easily in water?

Answer 41

NO

Question 42

What can have an impact on gases dissolving in wate?r

Answer 42

-Temperature: Generally an increase in temperature will decrease solubility