Properties of Water (and general Chem review)

Refer to the picture; the water is sticking to the spider web because of:

• Adhesion

• Cohesion

Describe COHESION.

• Water molecules attracted to other substances.

• Water molecules climbing upwards against the force of gravity.

• Water molecules dissolving many substances because of its polarity.

• Water molecules attracted to other water molecules.

Describe ADHESION.

• Water molecules attracted to other substances.

• Water molecules climbing upwards against the force of gravity.

• Water molecules dissolving many substances because of its polarity.

• Water molecules attracted to other water molecules.

What two elements make up water?

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

Tags

NGSS.MS-PS1-1

Attractions between water molecules are called

• Covalent bonds

• Ionic bonds

• Polar bonds

• Hydrogen bonds

Why does ice float?

• As water freezes, it expands and its density decreases.

• As water freezes, it takes up more hydrogen from the atmosphere

• As water freezes, air becomes trapped between the water molecules.

• As water freezes, it takes up more oxygen from the atmosphere

What type of bond attaches the oxygen and hydrogens together in a SINGLE water molecule?

• hydrogen bonds

• ionic bonds

• covalent bonds

Why can water striders walk across the surface of water without falling through?

• They are light enough so they don't break the hydrogen bonds holding the water molecules together

• The insects actually use their wings to hover slightly above the water’s surface

• 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

Tags

NGSS.MS-PS2-5

True or false water is a polar molecule? 

• True 
• False 

Tags

NGSS.HS-PS1-3

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