The Basics of Water

Question 1

Describe the structure of a water molecule.

Answer 1

A water molecule is composed of 3 atoms: 2 hydrogen attatched to one oxygen.

Question 2

What type of bond holds the atoms of a water molecule together?

Answer 2

Covalent bonds.

Question 3

What is the charge on each atom of a water molecule?

Answer 3

The oxygen molecule has a slightly negative charge, and the hydrogen has a slightly positive charge.

Question 4

Which atom of a water molecule has the most electrons around it, most of the time?

Answer 4

The oxygen atom has more electrons around it most of the time, giving it its slightly negative charge.

Question 5

What is the overall charge of a water molecule?

Answer 5

Neutral.

Question 6

A water molecule can be described as ‘polar’. Why is that?

Answer 6

A water molecule is polar because there is an unequal sharing of electrons around the atoms.

Question 7

Water is polar, and it forms polar bonds with other water molecules. What else can you call these polar bonds?

Answer 7

Hydrogen bonds.

Question 8

True or false: A hydrogen bond is weaker than a covalent bond.

Answer 8

True.

A hydrogen bond is weaker than a covalent bond and a hydrogen bond will always break much more easily than the covalent bond of an H2O molecule.

Question 9

A hydrogen bond is between which two atoms of water?

Answer 9

Hydrogen and oxygen.

Question 10

What is cohesion?

Answer 10

Attraction between particles of the same substance.

Question 11

When water molecules are attracted to each other, it is called. . .

Answer 11

Cohesion.

Question 12

What is one example of the cohesiveness of water?

Answer 12

Surface tension, water droplets.

Question 13

What is adhesion?

Answer 13

Attraction between two different substances.

Question 14

When water molecules form hydrogen bonds with substances other than itself, this is called. . .

Answer 14

Adhesion.

Question 15

What is an example of capillary action, and why does it occur?

Answer 15

Capillary action occurs due to water’s adhesive properties. Ex. transpiration, meniscus.

Question 16

High specific heat is. . .

Answer 16

The amount of heat required to raise 1g of a substance by 1°C.

Question 17

True or False: Water is resistant to temperature change.

Answer 17

True.

Due to high specific heat, water resists temp. change. This applies to both heating and cooling. Water takes a high amount of energy to heat and releases a large amount of energy when cooled. Thus, it can absorb or release lots of energy with little change in temp.

Question 18

The high specific heat of water is important because. . .

Answer 18

It allows a stable temperature, which is important in the bodies of living organisms and on the surface of the planet.

Question 19

High heat of vaporization is. . .

Answer 19

The amount of energy required to convert 1g of a substance from liquid to gas.

Water’s heat of vaporization is 540 cal/g.

Question 20

What type of bonds are broken when water turns into vapour?

Answer 20

Hydrogen bonds.

Question 21

As water evaporates, it produces a ________ effect.

Answer 21

A cooling effect.

Water that has vaporized takes energy with it.

Question 22

Why does ice float in liquid water?

Answer 22

Ice is less dense than liquid water.

This is due to the shape of the hydrogen bonds formed when water freezes, which creates pockets of space that allow for flotation.

Question 23

Frozen water forms bonds in a ____________ structure.

Answer 23

A ‘crystalline’ or ‘lattice’ structure.

Question 24

Why does water flow as a liquid?

Answer 24

In liquid form, water molecules constantly make, break and remake hydrogen bonds with one another.

Question 25

Water provides homeostasis, which is. . . ?

Answer 25

The ability to maintain a steady or consistent state of being, despite changing conditions.

Homeostasis benefits the biosphere, hydrosphere, lithosphere and atmosphere, providing conditions for life.

Question 26

Water is called the ‘univeral solvent’ because. . .

Answer 26

It is able to dissolve more substances than any other solvent on Earth.

Question 27

A solute is a substance that is. . .

Answer 27

Being dissolved.

Question 28

A solvent is a substance that is. . .

Answer 28

Dissolving something.

Question 29

Hydrophilic substances are. . .

Answer 29

Polar substances that dissolve in water.

Question 30

Hydrophobic substances are. . .

Answer 30

Non-polar substances that won’t dissolve in water.

Question 31

How do hydrophilic substances dissolve?

Answer 31

Its polarity is strong enough that they break the hydrogen bonds with each other and water will hydrogen bond around said hydrophilic substance.