AP Bio Review part 2

Large bodies of water do not quickly fluctuate in temperature. Why?

• Water is a solvent.
• Water has a high heat capacity.
• Water acts as a buffer.
• Water is non-polar.

The fact that ice floats on liquid water is due to the fact that water's solid is ___________ than it's liquid form

• less polar
• more polar
• less dense
• more dense

What makes a molecule polar?

• Equal sharing of valence electrons
• Unequal sharing of valence electrons
• Stealing of electrons
• Temporary charges that come and go

Water is an excellent solvent. Select the property that justifies this statement.

• as a polar molecule, it can surround and dissolve ionic and polar molecules

• it forms ionic bonds with ions, hydrogen bonds with polar molecules, and hydrophobic interactions with non polar molecules

• it forms hydrogen bonds with itself so cohesion is possible

• it is liquid and will adhere to many substances

The partial negative charge at one end of a water molecule is attracted to a partial positive charge of another water molecule. What is this type of attraction called?

• a polar covalent bond

• an ionic bond

• a hydration shell

• a hydrogen bond

 Small insects can walk across the surface of calm water. Their feet push the surface of the water down slightly, somewhat like a person walking across a trampoline, but they do not break the surface. What is the best explanation for why this happens?

• The insects are light enough so that they do not break the hydrogen bonds holding the water molecules together
• The insects actually use their wings to hover slightly above the water's surface and they only skim it with their feet
• The insects' feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water's surface
• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

A florist places a bouquet of white carnations in water containing blue dye. After a time, the flowers turn blue. What process helped the carnations to change color?

• Specific heat 
• Surface tension
• Cohesion and adhesion of water molecules 
• Formation of covalent bonds between hydrogen and oxygen molecules

Water makes up approximately 60% of the human body and plays a vital role in regulating body temperature. Which property of water makes it good at regulating temperature?

• Water is a good solvent.
• Water exhibits strong cohesion.
• . Water has an unusual crystalline structure.
• Water has a high capacity for heat.

Water has a much higher specific heat than most other covalent compounds. What do you predict might happen if water had a low specific heat instead?

• Flooding would occur and animals would be forced to migrate
•  Harmful organisms living in water would reproduce at a rapid rate
• Organisms that are sensitive to changes in temperature would die
• Plants would not have enough water to effectively carry out photosynthesis

 Many fish and aquatic plants can survive a cold winter because the layer of ice that forms at the top of the lake insulates the water below and prevents the lake from freezing solid. What unique property of water contributes to this effect? 

• Water absorbs heat when it evaporates and forms a gas 
•  Water expands and becomes less dense when it freezes.
• Water molecules completely separate into ions in solutions.
•  Water forms hydrogen bonds with ions and other polar substances.