1.2

Question 1

Water’s Importance

Water Molecules are special b/c:

Answer 1

• Universal solvent
  -60% makes up in body
• All cellular processes occurs in water
  -All living things contains water
• Simple and complex in stucture
• 10% denser as a liquid than as a solid

Water Molecules special b/c:
- shape
-Size
-Polar structure
- Ability to associate via hydrogen bonds

Question 2

Properties of Water:
Cohesion

Answer 2

• Water Molecules form hydrogen bonds, attracting each other
  -Attraction of like-molecules
• Results in surface tension

Question 3

Adhesion

Answer 3

• H2O attraction to diff molecules
  -Also form hydrogen bonds to those diff molecules
• Helps plants transport water (sticks to xylem)

Question 4

High Specific Heat Capacity

Answer 4

• Can absorb lots of thermal energy and release lots of thermal energy

-Helps organisms maintain constant body temperature

• Absorbs heat as it evaporates
• Organism cools themselves via evaporation

Question 5

Solid water is less dense than liquid water

Answer 5

• molecules are further apart when solid bc crystal structure it forms
• Therefore snow has high insulation value

Question 6

Water Molecules ability due to its polarity

Answer 6

• Very strong and polar
• Surround molecules, preventing them from reforming

Ex. salt dissolved in water

Question 7

Properties of Acids

Answer 7

• H+ is responsible for acidity
• Tastes sour, conducts electricity, turns litmus paper red

Question 8

Properties of bases

Answer 8

• OH+ is responsible
• Tastes bitter, slippery, turns litmus paper blue

Question 9

Buffer System

• LOOK AT BUFFER DIAGRAM

Answer 9

• Living organisms use a buffer system to control their internal pH
• Weak bases/Acids act as buffer since most of their reactions are reversible
• Chemical that changes pH by accepting or releasing H+ ions
• Our blood needs pH of 7.35-7.45