1.2 - Water: Life’s Solvent Flashcards
Why is Water so Important?
Water is known as the “Universal Solvent” and helps to dissolve many substances
Approximately 60% of your body is water
Virtually all cellular processes occur in water
ALL LIVING THINGS contain water
What is cohesion? What does it do?
Force of attraction between like molecules
Water molecules form hydrogen bonds with each other
This results in surface tension and allows small insects/spiders to walk on water
What is Adhesion? What does it do? Why do we use it?
Adhesion – force of attraction between different molecules
Water molecules may also form hydrogen bonds with other polar molecules
Helps plants transport water (sticks to xylem)
Allows water to dissolve polar substances
What is high specific heat capacity?
Water can absorb large amounts of thermal energy when heated (also releases large amounts of thermal energy as it cools)
Helps organisms maintain a constant body temperature (holds heat)
What is High Specific Heat of Vaporization
Water absorbs large amounts of heat as it evaporates
Many organisms cool themselves through evaporation (sweating)
What is Solid Water is Less Dense than Liquid Water?
As water cools the water molecules form a lattice structure that spreads the molecules farther apart thus lowering density
The result is that ICE FLOATS!
Prevents ice from killing aquatic organisms
Snow has a very high insulation value – keeps critters warm in winter
What is an aqueous solution?
Water molecules are STRONGLY POLAR
They surround other atoms/molecules and prevent them from reforming
What is hyrdophilic?
Polar substances that are attracted to water (ex. Salt)
What is hydrophobic?
Non-polar substances that are not attracted to water (ex. Oil)
What are acids and bases?
We use a system called the pH scale to measure how ACIDIC or BASIC a solution is.
What are the pH levels for acid, base and neutral?
Acidic = Low pH
Basic = High pH
Neutral = pH 7
What are the properties of acids?
H3O+ ions are responsible for acidity (H3O+ > OH- = acidic)
Taste Sour, Conduct Electricity, Turns Blue Litmus paper Red
What are properties of bases?
OH- ions are responsible for alkalinity (basic) (OH- > H3O+ = Basic)
Taste Bitter, Feel Slippery, Conducts Electricity, Turns Red Litmus paper Blue
What are strong acids/bases?
Completely dissociates in water
What are weak acids/bases?
Only a small percentage of the molecules dissociate in water
