6-2: Water

A water strider can skate along the top of a pond because:

• covalent bonds result in water cohesion
• hydrogen bonds result in water cohesion (surface tension)
• water striders have adapted to take advantage of water cohesion
• low surface tension of water

What word describes when water is attracted to other substances?

• cohesion
• adhesion
• capillary action
• surface tension

What two elements make up water?

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

Attractions between water molecules 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

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.

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.

molecule in which opposite ends have opposite electric charges

• cohesion
• polar molecule
• hydrogen bond
• solution

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.

Which end of the water molecule has a slightly positive charge?

• the oxygen end
• the hydrogen end
• both ends are slightly positive
• neither end is positive