1.1 Properties Of Water

Question 1

Polarity makes water a polar molecule. How?

Answer 1

• unequal sharing of electrons

Question 2

What is cohesion?

Answer 2

• attraction of molecules for other molecules of the same kind

Question 3

What type of bonds increase cohesive forces of water?

Answer 3

• hydrogen bonds between water molecules hold them together and increase cohesive forces

Question 4

What does cohesion allow to happen? (2)

Answer 4

• allows for the transport of water and nutrients against gravity in plants
• responsible for surface tension

Question 5

What is surface tension?

Answer 5

• property allowing liquids to resist external force

Question 6

What is adhesion?

Answer 6

• The clinging of one molecule to a different molecule

- due to the polarity of water

Question 7

What does adhesion allow for in plants?

Answer 7

• allows for water to cling to the cell walls to resist the downward pull of gravity

Question 8

What is capillary action?

Answer 8

• the upward movement of water due to the forces of cohesion, adhesion, and surface tension

Question 9

When does capillary action occur?

Answer 9

• when adhesion is greater than cohesion

Question 10

Why is capillary action important to plants?

Answer 10

Important for transport of water and nutrients in plants

Question 11

What is high specific heat in water? (2)

Answer 11

• water resists changes in temperature

- the amount of energy required to raise 1 g of water by 1 degree Celsius

Question 12

How does water have a high specific heat? (2)

Answer 12

• through hydrogen bonds

- must be absorbed to break oxygen bonds, but heat is released when hydrogen bonds form

Question 13

Why is high specific heat important? (3)

Answer 13

• it moderates air temperature because large bodies of water can absorb heat in the day and release heat at night
• stabilizers ocean temperature, which benefits marine life
• organisms can resist changes in their own internal temperature

Question 14

What is evaporative cooling? (2)

Answer 14

• Water has a high heat vaporization

- the molecule with the highest kinetic energy leave as gas

Question 15

Why is evaporative cooling important? (4)

Answer 15

1. Moderates Earth’s climate
2. Stabilizes temp in lakes and ponds
3. Prevents terrestrial organisms from overheating (like sweating in humans)
4. Prevents leaves from becoming too warm in the sun

Question 16

What is density (floating ice)?

Answer 16

• as water solidifies, it expands and becomes less dense due to the hydrogen bonds

Question 17

How does floating ice occur?

Answer 17

• when cooled, water molecules move too slowly to break bonds
• hydrogen bonds cause water molecules to form a crystalline structure (creates lots of space meaning less density)

Question 18

Why is floating ice important?

Answer 18

Allows marine life to survive under floating ice sheets

Question 19

What is a solvent?

Answer 19

• dissolving agent in a solution

Question 20

What is a solution?

Answer 20

• homogenous mixture of two or more substances

Question 21

What is a solute?

Answer 21

• substance that is dissolved (salt)

Question 22

Why is water a versatile solvent? (2)

Answer 22

• it’s polar molecules are attracted to ions and other polar molecules it can form hydrogen bonds with
  Note that water is a universal solvent because it can dissolve other molecules due to its polarity

Question 23

What does “like dissolve like” mean? (2)

Answer 23

• water can interact with sugars or proteins containing many oxygen and hydrogen
• water will form hydrogen bonds with the sugar or protein to dissolve it

Question 24

How will water interact with ionic compounds? (3)

Answer 24

• The partially negative oxygen in the water will interact with a positive atom
• the partial positive hydrogen in water will interact with a negative atom
• dissolves ion

Question 25

What are the 7 properties of water?

Answer 25

1. Polarity
2. Cohesion (surface tension)
3. Adhesion
4. capillary action
5. Temperature control (high specific heat, evaporative cooling)
6. Density (floating ice)
7. Solvent (versatile and universal solvent)