AP Biology - Water

What property of water allows it to be such a versatile solvent that it is often called the "universal solvent?"

• Purity

• Polarity

• High heat capacity

• Expansion upon freezing

Which of the following properties of water enables molecules to cling together as they move from the roots to the leaves of plants?

• Water expands as it freezes.

• Water is an excellent solvent.

• Water exhibits cohesive behavior.

• Water moderates temperature.

Capillary action is the result of adhesion. Which aspect of water is responsible for this?

• Nonpolar covalent bonds enable water to dissolve other substances.

• Polar covalent bonds join molecules of water to other substances.

• Hydrogen bonds form between water and another substance.

• Ionic bonds enable electrons to flow through water and into another substance.

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

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

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

Some insects can stand on the surface of calm water. Their feet push the surface of the water down slightly, but they do not break the surface. Why?

• The insects are light enough so 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 insect’s 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
  

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NGSS.MS-PS2-5

What term describes when water is attracted to other substances?

• Cohesion
• Adhesion
• Capillary Action
• Surface Tension

Why does water move from the roots to the leaves of plants?

• Water is pushed up by solutes.

• Cohesion and adhesion resulting from hydrogen bonding due to water being a polar molecule

• Water is pulled up by gravity.

Attractions between water molecules due to polarity are called:

• Covalent bonds
• Ionic bonds
• Polar bonds
• Hydrogen bonds

The attraction that causes water and other liquids to form drops on thin films is called ________________. This is also water’s ability to be attraction to other water molecules.

• adhesion
• capillary action
• cohesion
• surface tension

Why does ice float?

• As water freezes, it expands and its density decreases.
• As water freezes, it takes up more hydrogen from the atmosphere, causing it to have a greater buoyancy.
• As water freezes, air becomes trapped between the hydrogen bonds of water molecules.
• As water freezes, it takes up more oxygen from the atmosphere, causing it to have a greater buoyancy.