Properties of Water

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.

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

• Purity
• Polarity and cohesion
• High heat capacity
• Expansion upon freezing

Water striders can walk across 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
  

What two elements make up water?

• Helium and oxygen
• Hydrogen and oxygen
• helium and carbon
• oxygen and carbon

What word 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 by solutes
• Capillary action pulls the water molecules like a chain
• Water is pulled by gravity
• Water’s cohesion causes it to “pull” towards the leaves

Attractions between water molecules are called

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

Which is NOT a unique property of water?

• Frozen water floats on liquid water.
• Water covers most of the Earth’s surface and retains a large amount of heat.
• Water molecules stick to each other through hydrogen bonds.
• Water cools very rapidly.

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.

Water is polar because...

• The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.
• The molecule has two poles, at which the it is colder than other regions of the molecule.
• The unequal sharing of electrons gives the water molecule a slight negative charge near its hydrogen atoms and a slight positive charge near its oxygen atom.
• The water molecule is neutral.