pH and Water

Question 1

Describe cohesion in water

Answer 1

hydrogen bonds hold water molecules together

Question 2

________ helps the transport of water against gravity in plants

Answer 2

Cohesion

Question 3

Define adhesion

Answer 3

an attraction between different substances, for example, between water and plant cell walls

Question 4

Describe hydrogen bonding

Answer 4

the oxygen ion in water are slightly negative, whereas the hydrogen ions are slightly positive. the oxygen ion of one water molecule is attracted to the hydrogen ions of the other water molecule

Question 5

How does cohesion, adhesion, and surface tension help plant veins transport water?

Answer 5

the water molecules are initially attracted to the vein’s surface through adhesion. this creates a small clump of water molecules at the base of the vein. other water molecules attach to this initial clump through cohesion. surface tension helps water climb up the vein.

Question 6

Define surface tension

Answer 6

a measure of how hard it is to break the surface of a liquid

Question 7

Surface tension is related to what property of water?

Answer 7

cohesion

Question 8

Describe how water helps with the regulation of temperature

Answer 8

Water absorbs heat from warmer areas and releases this heat in cooler areas. Water is able to do this without much temperature change due to its high specific heat capacity.

Question 9

Describe evaporative cooling of water

Answer 9

As a liquid evaporates, its remaining surface cools.

Question 10

Define solution

Answer 10

a liquid that is a homogeneous mixture of substances

Question 11

Define solvent

Answer 11

is what things dissolve in

Question 12

Define solute

Answer 12

the substance that is dissolved

Question 13

Water is a versatile solvent due to its _______

Answer 13

polarity

Question 14

Describe why hydrophilic substances dissolve in water

Answer 14

The polarity of hydrophilic substances are stronger than the cohesive forces of the water

Question 15

What is a hydration shell?

Answer 15

When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called a hydration shell

Question 16

Define hydrophilic

Answer 16

affinity for water

Question 17

Define hydrophobic

Answer 17

does not have an affinity for water

Question 18

Why does ice float on water?

Answer 18

When water freezes, the hydrogen bonds that keep the molecules together freeze into a crystalline structure. This causes the frozen water molecules to be evenly spaced apart. This means that ice is less dense than water.

Question 19

Why is the density properties of water so important to life on Earth?

Answer 19

if ice was more dense than water, then ice would sink to the bottom of bodies of waters. This would eventually cause all bodies of water to freeze solid.

Question 20

Water is in a state of __________ __________ in which water molecules can break up and reform.

Answer 20

dynamic equilibrium

Question 21

When water gains a hydrogen ions it becomes a ___________ ____

Answer 21

hydronium ion

Question 22

The molecule that lost the hydrogen is now a ___________ _____

Answer 22

hydroxide ion

Question 23

Bases contains extra hydronium or hydroxide ions?

Answer 23

hydroxide ions

Question 24

Acids contain extra hydronium or hydroxide ions?

Answer 24

hydronium ions

Question 25

The internal pH of most living cells must remain close to pH _

Answer 25

7

Question 26

What is acid precipitation?

Answer 26

rain, snow, or fog with a pH lower than 5.6

Question 27

What causes acid precipitation?

Answer 27

fossil fuels

Question 28

What are the effects of acid precipitation on the environment?

Answer 28

damage life in forests, lakes, streams, and oceans (coral reefs have lack of calcification)
Effects of acid precipitation on soil chemistry are contributing to the decline of some forests

Question 29

How does hydrogen bonding relate to polar substances dissolving in water?

Answer 29

the hydrogen bonds in water attach to the hydrogen bonds of the polar substances instead of other water molecules

Question 30

How does hydrogen bonding relate to evaporative cooling?

Answer 30

when the water molecules evaporate, the hydrogen bonds break away and this releases energy in the process.