Module 3.1 H Bonds & Properties of Water

Question 1

Waters life-giving properties

Answer 1

• Ice is less dense than water
• Water changes temperature slowly
• Water exhibits cohesion
• Water is an excellent solvent

Water is essential for life and makes up a significant portion of the earth’s surface.

Question 2

What percentage of the earth is covered in water?

Answer 2

70%

Question 3

What percentage of our cells is made up of water?

Answer 3

70-95%

Water is primarily found in the cytoplasm/cytosol or intracellular fluid (ICF).

Question 4

Water bathes our cells in

Answer 4

extracellular fluid (ECF)​

Question 5

Extracellular fluid (ECF)​

Answer 5

the fluid outside all cells of the body. Is composed primarily of interstitial fluid and plasma, and plays a crucial role in maintaining homeostasis and facilitating the exchange of substances between cells and their environment.

Question 6

Middle of a cell is called a

Answer 6

Cytoplasm or the cytosal or “the soup.” It’s a watery environment

Question 7

What is the structure of water in terms of polarity?

Answer 7

Water is a polar molecule

Oxygen is electronegative, attracting electrons, making oxygen partly negative and hydrogen partly positive.

Question 8

Oxygen in water is

Answer 8

electronegative

Question 9

Water has a big, strong

Answer 9

Oxygen

Question 10

Water will always pull electrons towards

Answer 10

the oxygen

Question 11

Water attracts the electrons of the

Answer 11

single covalent bonds

Question 12

Water is what kind of bond?

Answer 12

A polar covalent bond.

Question 13

Polar covalent bond has a difference of

Answer 13

polarity

Question 14

The oxygen in water is partly

Answer 14

negative

Question 15

The hydrogen in water is partly

Answer 15

positive

Question 16

What type of bond forms between a partly negative atom of a molecule and a partly positive hydrogen of a different molecule?

Answer 16

Hydrogen bonds

These bonds occur in polar covalent bonds, typically involving oxygen or nitrogen.

Question 17

Water molecules can form up to how many hydrogen bonds?

Answer 17

4 bonds with 4 different water molecules

Question 18

Hydrogen bonds must have an electronegative atom attached to a

Answer 18

hydrogen

Question 19

In living organisms, most hydrogen bonds involve molecules with

Answer 19

–OH or –NH

Question 20

Are hydrogen bonds strong or weak?

Answer 20

Weakest of all bonds

Hydrogen bonds are usually represented by dashed or dotted lines.

Question 21

What are the three states of matter in which water can exist?

Answer 21

Solid, Liquid, Gas

Water’s hydrogen bonds keep it liquid over a temperature range of 0 – 100 °C.

Question 22

Hydrogen bonds between water molecules keep it liquid over a range of

Answer 22

0 – 100oC

Question 23

Water is known as the

Answer 23

solvent of life

Question 24

Water dissolves by forming a what around molecules?

Answer 24

hydration shell

Question 25

What is a hydration shell?

Answer 25

A structure formed around molecules in water ## Footnote It occurs when partly positive hydrogens attract chloride ions and partly negative oxygens attract sodium ions.

Question 26

When water dissolves sodium chloride, what happens?

Answer 26

Partly positive hydrogens are attracted to the chloride ions​ Partly negative oxygens are attracted to the sodium ions

Question 27

Polar molecules such as sugar and ammonia also

Answer 27

dissolve in water

Question 28

Around the solute, water forms

Answer 28

spheres of hydration

Question 29

What is the term for molecules that are 'water-hating'?

Answer 29

Hydrophobic ## Footnote Examples include oil.

Question 30

What is the term for molecules that are 'water-loving'?

Answer 30

Hydrophilic ## Footnote Water soluble vitamins are hydrophilic.

Question 31

Water soluble vitamins are

Answer 31

hydrophilic​

Question 32

Hydrophilic molecules are

Answer 32

polar

Question 33

All polar molecules are

Answer 33

"water-loving," so they can dissolve in water

Question 34

Hydrophobic molecules are

Answer 34

nonpolar

Question 35

Hydrophobic molecules cannot dissolve/interact in/with water because they cannot

Answer 35

form hydrogen bonds with water

Question 36

Molecules that are both "water-loving" and "water-hating"

Answer 36

Have a hydrophobic end and a hydrophilic end

Question 37

Evaporation

Answer 37

transitioning from a liquid state to a gaseous state

Question 38

Evaporation occurs

Answer 38

at the surface of a liquid

Question 39

In order for evaporation to occur, Molecules must be moving fast enough to

Answer 39

break the hydrogen bonds holding them together​

Question 40

Boiling is similar to

Answer 40

evaporation

Question 41

Boiling occurs

Answer 41

throughout the liquid

Question 42

Boiling is a

Answer 42

quick process

Question 43

What is the heat of vaporization?

Answer 43

The amount of heat needed to convert 1 gram of substance from liquid to gas ## Footnote Water requires about 560 calories of heat to evaporate 1 gram.

Question 44

Water has a high

Answer 44

heat of vaporization

Question 45

To evaporate water, water needs

Answer 45

about 560 calories of heat to evaporate 1 gram of water

Question 46

Specific heat is the

Answer 46

amount of heat needed to raise 1 gram of water 1oC

Question 47

Water has high

Answer 47

specific heat

Question 48

Water takes a long time to

Answer 48

heat up and cool down

Question 49

Water stays liquid over a wide

Answer 49

range of temperatures

Question 50

What is the boiling point of water?

Answer 50

100 °C ## Footnote This boiling point is much higher than that of other nonpolar molecules of similar size.

Question 51

The boiling point of water is much higher than

Answer 51

other nonpolar molecules of similar size

Question 52

Cohesion

Answer 52

the result of hydrogen bonds between water molecules. So, water sticking to water

Question 53

Cohesion creates

Answer 53

surface tension (why water strides can ride at the top of water or little water droplets on leaves)

Question 54

What is cohesion in relation to water?

Answer 54

The sticking together of water molecules. ## Footnote It results from hydrogen bonds between water molecules.

Question 55

What creates surface tension in water?

Answer 55

Stronger hydrogen bonds at the surface ## Footnote Surface tension occurs when water molecules at the surface bond more strongly with adjacent molecules.

Question 56

Surface tension occurs when

Answer 56

water molecules at the surface form stronger hydrogen bonds with the water molecules on either side​

Question 57

Adhesion

Answer 57

Occurs when hydrogen bonds form between water molecules and other polar molecules​. So, water sticking to other different molecules

Question 58

What is adhesion in relation to water?

Answer 58

The sticking of water molecules to other polar molecules ## Footnote This occurs due to hydrogen bonds forming between water and different molecules.

Question 59

Water is a good what and what?

Answer 59

Lubricant and cushion

Question 60

Why is water considered a good lubricant?

Answer 60

It reduces friction in joints and around organs ## Footnote Examples include the joints of the knee and around the heart.

Question 61

What role does water play as a cushion in the body?

Answer 61

It cushions the brain and is in the amniotic fluid that protects the fetus ## Footnote Amniotic fluid is an example of water cushioning.